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Lu X, Goulding RP, Mundel T, Schlader ZJ, Cotter JD, Koga S, Fujii N, Wang IL, Liu Z, Li HY, Wang H, Zheng H, Kondo N, Gu CY, Lei TH, Wang F. Interactive effects of exercise intensity and recovery posture on post-exercise hypotension. Am J Physiol Regul Integr Comp Physiol 2024. [PMID: 38646812 DOI: 10.1152/ajpregu.00036.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 04/15/2024] [Indexed: 04/23/2024]
Abstract
Post-exercise reduction in blood pressure, termed post-exercise hypotension (PEH), is relevant for both acute and chronic health reasons and potentially for peripheral cardiovascular adaptations. We investigated the interactive effects of exercise intensity and recovery postures (seated, supine, and standing) on PEH. Thirteen normotensive men underwent a VO2max test on a cycle ergometer and 5 exhaustive constant load trials to determine critical power (CP) and the gas exchange threshold (GET). Subsequently, work-matched exercise trials were performed at two discrete exercise intensities (10% > CP and 10% < GET), with one hour of recovery in each of three postures. For both exercise intensities, standing posture resulted in a more substantial PEH (all P < 0.01). For both standing and seated recovery postures, the higher exercise intensity led to larger reductions in systolic, diastolic and mean arterial pressures (all P < 0.01), whereas in the supine recovery posture, the reduction in diastolic and mean arterial pressures was unaffected by prior exercise intensity (both P > 0.05). PEH is more pronounced during recovery from exercise performed above critical power versus below GET. However, the effect of exercise intensity on PEH is largely abolished when recovery is performed in the supine posture.
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Affiliation(s)
- Xueer Lu
- Hubei Normal University, Shenzhen, China
| | | | - Toby Mundel
- Kinesiology, Brock University, St. Catharines, Canada
| | - Zachary J Schlader
- Department of Kinesiology, Indiana University Bloomington, Bloomington, IN, United States
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Shunsaku Koga
- Applied Physiology Laboratory, Kobe Design University, Kobe, Japan
| | - Naoto Fujii
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - I-Lin Wang
- College of physical education, Hubei Normal University, China
| | - Ziyang Liu
- Hubei Normal University, Huangshi, China
| | - Hao-Yu Li
- Hubei Normal University, Huangshi, China
| | - Hui Wang
- Laboratory for Applied Human Physiology, Kobe University, kobe, , Japan
| | - Huixin Zheng
- School of Sport Exercise and Nutrition, Massey University, Palmerston North, New Zealand
| | - Narihiko Kondo
- Laboratory for Applied Human Physiology, Kobe University, Kobe, Japan
| | - Chin-Yi Gu
- Hubei Normal University, Huangshi, China
| | - Tze-Huan Lei
- College of Physical Education, Hubei Normal University, Huangshi, China
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Roxburgh BH, Campbell HA, Cotter JD, Reymann U, Williams MJA, Gwynne-Jones D, Thomas KN. Upper-Limb High-Intensity Interval Training or Passive Heat Therapy to Optimize Cardiorespiratory Fitness Prior to Total Hip or Knee Arthroplasty: A Randomized Controlled Trial. Arthritis Care Res (Hoboken) 2024; 76:393-402. [PMID: 37728076 DOI: 10.1002/acr.25238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 08/30/2023] [Accepted: 09/15/2023] [Indexed: 09/21/2023]
Abstract
OBJECTIVE Preoperative exercise training, or prehabilitation, aims to optimize cardiorespiratory fitness before surgery to reduce the risk of adverse perioperative events and delayed recovery. However, traditional exercise such as walking and cycling can be difficult for people with degenerative joint diseases of the lower limbs, such as osteoarthritis. The purpose of this study was to compare the effect of three low-impact interventions on cardiorespiratory fitness, physical function, and subjective health before total hip or knee arthroplasty. METHODS This was a randomized controlled trial involving 93 participants with severe knee or hip osteoarthritis awaiting joint replacement surgery. Participants underwent cardiopulmonary exercise testing (to measure peak oxygen consumption [V ̇ $$ \dot{V} $$ O2 ]), then were randomized to heat therapy (Heat; 20-30 min immersed in 40°C water followed by ~15 min light-resistance exercise), high-intensity interval training (HIIT; 6-8 × 60 s intervals on a cross-trainer or arm ergometer at ~90%-100% peakV ̇ $$ \dot{V} $$ O2 ), or home-based exercise (Home; ~15 min light-resistance exercise); for up to 36 sessions (3 sessions per week for 12 weeks). RESULTS PeakV ̇ $$ \dot{V} $$ O2 increased by 16% across HIIT and to a greater extent than Heat (+2.5 mL × min-1 × kg-1 [95% CI: 0.5-4.4], P = 0.009) and Home (+3.2 mL × min-1 × kg-1 [1.2-5.2], P = 0.001). The anaerobic threshold increased across HIIT (+1.5 mL × min-1 × kg-1 [0.7-2.3], P < 0.001) and Heat (+1.2 mL × min-1 × kg-1 [0.4-1.9], P = 0.004), but not Home (-0.5 mL × min-1 × kg-1 [-1.3 to 0.3], P = 0.248). Subjective severity of osteoarthritis was unchanged with any intervention (P ≥ 0.250). CONCLUSION Heat therapy and HIIT improved indices of cardiorespiratory fitness preoperatively in patients who have difficulty performing lower-limb exercise.
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Otsuka J, Okamoto Y, Enoki Y, Maejima D, Fujii N, Kenny GP, Mündel T, Cotter JD, Amano T. Effects of ingesting beverages containing glycerol and sodium with isomaltulose or sucrose on fluid retention in young adults: a single-blind, randomized crossover trial. Appl Physiol Nutr Metab 2024. [PMID: 38377479 DOI: 10.1139/apnm-2023-0483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
We evaluated changes in hyperhydration and beverage hydration index (BHI, a composite measure of fluid balance after consuming a test beverage relative to water) during resting, induced by the consumption of beverages containing glycerol and sodium supplemented with fast-absorbing sucrose or slow-absorbing isomaltulose. In a randomized crossover, single-blinded protocol (clinical trials registry: UMIN000042644), 14 young physically active adults (three women) consumed 1 L of beverage containing either 7% glycerol + 0.5% sodium (Gly + Na), Gly + Na plus 7% sucrose (Gly + Na + Suc), Gly + Na plus 7% isomaltulose (Gly + Na + Iso), or water (CON) over a 40 min period. We assessed the change in plasma volume (ΔPV), BHI (calculated from cumulative urine output following consumption of water relative to that of the beverage), and blood glucose and sodium for 180 min after initiating ingestion. Total urine volume was reduced in all beverages containing glycerol and sodium compared to CON (all P ≤ 0.002). The addition of isomaltulose increased BHI by ∼45% (3.43 ± 1.0 vs. 2.50 ± 0.7 for Gly + Na, P = 0.011) whereas sucrose did not (2.6 ± 0.6, P = 0.826). The PV expansion was earliest for Gly + Na (30 min), slower for Gly + Na + Suc (90 min), and slowest for Gly + Na + Iso (120 min) with a concomitant lag in the increase of blood glucose and sodium concentrations. Supplementation of beverages containing glycerol and sodium with isomaltulose but not sucrose enhances BHI from those of glycerol and sodium only under a resting state, likely due to the slow absorption of isomaltulose-derived monosaccharides (i.e., glucose and fructose).
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Affiliation(s)
- Junto Otsuka
- Laboratory for Exercise and Environment Physiology, Faculty of Education, Niigata University, Niigata, Japan
| | - Yumi Okamoto
- Laboratory for Exercise and Environment Physiology, Faculty of Education, Niigata University, Niigata, Japan
| | - Yasuaki Enoki
- Advanced Research Institutes, Bourbon Corporation, Niigata, Japan
| | - Daisuke Maejima
- Advanced Research Institutes, Bourbon Corporation, Niigata, Japan
| | - Naoto Fujii
- Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Toby Mündel
- Department of Kinesiology, Brock University, St. Catharines, ON, Canada
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago, Dunedin, New Zealand
| | - Tatsuro Amano
- Laboratory for Exercise and Environment Physiology, Faculty of Education, Niigata University, Niigata, Japan
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van Duijn T, Button C, Cotter JD, Masters RSW. Energetic and Cognitive Demands of Treading Water: Effects of Technique and Expertise. J Sports Sci Med 2023; 22:726-738. [PMID: 38045755 PMCID: PMC10690517 DOI: 10.52082/jssm.2023.726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 11/01/2023] [Indexed: 12/05/2023]
Abstract
Being able to tread water effectively can improve the likelihood of survival following accidental immersion. People tread water in various ways, ranging from rudimentary 'doggy-paddle' to more elaborate techniques like the eggbeater, but little is known about the energetic and cognitive requirements of treading water. We therefore aimed to measure the demands of treading water techniques for people of different experience levels. Three cohorts, comprising 21 adult water treading experts (water polo players), 15 intermediate swimmers and 16 inexperienced swimmers, treaded water for 3 min each using four different techniques while cognitive and energetic economy measures were taken. For inexperienced swimmers, the flutter kick and breaststroke patterns produced the lowest self-reported physical and task load (rating of perceived exertion, NASA task load index), while cognitive (probe reaction time), cardiac (heart rate) and metabolic (oxygen consumption) load did not differ between techniques. In contrast, for expert water treaders, both breaststroke and eggbeater patterns produced lower cognitive, cardiac and metabolic loads. For intermediate swimmers, breaststroke resulted in the lowest cardiac and metabolic loads, as well as self-reported task load. Probe reaction time was highest while performing the eggbeater technique, indicating that this technique was challenging to coordinate and cognitively demanding. While the energetic demands of antiphase kicking patterns (such as eggbeater in experts or flutter kick in beginners) may be similarly low, the symmetric coordination of upright breaststroke may explain why this pattern's cognitive economy was favourable for all groups. As the eggbeater can be challenging to perform for many people, an upright breaststroke technique is an adequate alternative to adopt in survival situations.
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Affiliation(s)
- Tina van Duijn
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
- Human Performance Research Center, Faculty of Health, University of Technology Sydney, Australia
- School of Sport, Exercise and Rehabilitation, University of Technology Sydney, Australia
| | - Chris Button
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Rich S W Masters
- Te Huataki Waiora School of Health, University of Waikato, Hamilton, New Zealand
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Roxburgh BH, Campbell HA, Cotter JD, Reymann U, Williams MJA, Gwynne-Jones D, Thomas KN. Acute and adaptive cardiovascular and metabolic effects of passive heat therapy or high-intensity interval training in patients with severe lower-limb osteoarthritis. Physiol Rep 2023; 11:e15699. [PMID: 37300374 DOI: 10.14814/phy2.15699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 04/27/2023] [Indexed: 06/12/2023] Open
Abstract
Exercise is painful and difficult to perform for patients with severe lower-limb osteoarthritis; consequently, reduced physical activity contributes to increased cardiometabolic disease risk. The aim of this study was to characterize the acute and adaptive cardiovascular and metabolic effects of two low or no impact therapies in patients with severe lower-limb osteoarthritis: passive heat therapy (Heat) and high-intensity interval training (HIIT) utilizing primarily the unaffected limbs, compared to a control intervention of home-based exercise (Home). Participants completed up to 12 weeks of either Heat (20-30 min immersed in 40°C water followed by ~15-min light resistance exercise), HIIT (6-8 × 60-s intervals on a cross-trainer or arm ergometer at ~90-100% peak V ̇ $$ \dot{V} $$ O2 ) or Home (~15-min light resistance exercise); all 3 sessions/week. Reductions in systolic (12 & 10 mm Hg), diastolic (7 & 4 mm Hg), and mean arterial (8 & 6 mm Hg) blood pressure (BP) were observed following one bout of Heat or HIIT exposure, lasting for the duration of the 20-min monitoring period. Across the interventions (i.e., 12 weeks), resting systolic BP and diastolic BP decreased with Heat (-9 & -4 mm Hg; p < 0.001) and HIIT (-7 & -3 mm Hg; p ≤ 0.011), but not Home (0 & 0 mm Hg; p ≥ 0.785). The systolic and diastolic BP responses to an acute exposure of Heat or HIIT in the first intervention session were moderately correlated with adaptive responses across the intervention (r ≥ 0.54, p ≤ 0.005). Neither intervention improved indices of glycemic control (p = 0.310). In summary, both Heat and HIIT induced potent immediate and adaptive hypotensive effects, and the acute response was moderately predictive of the long-term response.
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Affiliation(s)
- Brendon H Roxburgh
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
- HeartOtago, University of Otago, Dunedin, New Zealand
| | - Holly A Campbell
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
- HeartOtago, University of Otago, Dunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
- HeartOtago, University of Otago, Dunedin, New Zealand
| | - Ulla Reymann
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Michael J A Williams
- HeartOtago, University of Otago, Dunedin, New Zealand
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - David Gwynne-Jones
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
- Department of Orthopaedic Surgery, Dunedin Hospital, Southern District Health Board, Dunedin, New Zealand
| | - Kate N Thomas
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
- HeartOtago, University of Otago, Dunedin, New Zealand
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Abstract
Endurance exercise induces cardiovascular adaptations; the athletic phenotypes of the heart and arteries are well characterised, but few studies have investigated the effects of chronic exercise on the venous system. The aim of this study was to describe the anatomy and function of lower limb deep and superficial veins in athletes compared to controls. Endurance-trained athletes and untrained controls (13 males, 7 females per group) were examined utilising ultrasound to measure vein diameter and flow, and air plethysmography to assess calf venous volume dynamics and muscle pump function at rest, during a single step, ambulation (10 steps) and after acute treadmill exercise (30 min ~80% age-predicted heart rate maximum). Diameters of 3 of the 7 deep veins assessed were larger in athletes (P≤0.0167) and more medial calf perforators were detectable (5 vs. 3, P=0.0039). Calf venous volume was 22% larger in athletes (P=0.0057), calf muscle pump ejection volume and ambulatory venous volume after 10 steps were both greater in athletes (20 and 46% respectively, P≤0.0482). Following acute exercise, flow recovery profiles in deep and superficial veins draining the leg were not different between groups, despite athletes performing ~four times more work. After exercise, venous volume and ejection volume were reduced by ~20% in athletes with no change in controls (interaction P≤0.0372) and while ambulatory venous volume reduced, this remained greater in athletes. These findings highlight venous adaptations that compensate for the demands of regular endurance exercise, all of which are suited to enhance flow through the lower limb venous system.
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Affiliation(s)
- Kate N Thomas
- Department of Surgical Sciences, Dunedin School of Medicine, Dunedin, New Zealand
| | - Ashley P Akerman
- Department of Surgical Sciences, Dunedin School of Medicine, Dunedin, New Zealand
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Travis D Gibbons
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan, School of Health and Exercise Science, Kelowna, British Columbia, Canada
| | - Holly A Campbell
- Department of Surgical Sciences, Dunedin School of Medicine, Dunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - André M van Rij
- Department of Surgical Sciences, Dunedin School of Medicine, Dunedin, New Zealand
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Jenkins EJ, Campbell HA, Lee JKW, Mündel T, Cotter JD. Delineating the impacts of air temperature and humidity for endurance exercise. Exp Physiol 2023; 108:207-220. [PMID: 36537856 PMCID: PMC10103870 DOI: 10.1113/ep090969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022]
Abstract
NEW FINDINGS What is the central question of this study? What are the independent effects of air temperature and humidity on performance, physiological and perceptual responses during endurance exercise? What is the main finding and its importance? When examined independently, elevated air temperature increased heat strain and impaired aerobic exercise performance, but to a lesser extent than has been reported previously. These findings highlight the importance of absolute humidity relative to temperature when exercising or working under severe heat stress. ABSTRACT Many studies have reported that ambient heat stress increases physiological and perceptual strain and impairs endurance exercise, but effects of air temperature per se remain almost unexamined. Most studies have used matched relative humidity, thereby exponentially increasing absolute humidity (water content in air) concurrently with temperature. Absolute (not relative) humidity governs evaporative rate and is more important at higher work rates and air temperatures. Therefore, we examined the independent effects of air temperature and humidity on performance, thermal, cardiovascular and perceptual measures during endurance exercise. Utilizing a crossover design, 14 trained participants (7 females) completed 45 min fixed-intensity cycling (70%V ̇ O 2 peak ${\dot V_{{{\rm{O}}_{\rm{2}}}{\rm{peak}}}}$ ) followed by a 20-km time trial in each of four environments: three air temperatures at matched absolute humidity (Cool, 18°C; Moderate, 27°C; and Hot, 36°C; at 1.96 kPa, air velocity ∼4.5 m/s), and one at elevated humidity (Hot Humid, 36°C at 3.92 kPa). Warmer air caused warmer skin (0.5°C/°C; P < 0.001), higher heart rate (1 bpm/°C; P < 0.001), sweat rate (0.04 l/h/°C; P < 0.001) and thermal perceptions during fixed-intensity exercise, but minimally affected core temperature (<0.01°C/°C; P = 0.053). Time-trial performance was comparable between Cool and Moderate (95% CI: -1.4, 5.9%; P = 0.263), but 3.6-6% slower in Hot (95% CI: ±2.4%; P ≤ 0.006). Elevated humidity increased core temperature (P < 0.001), perceived temperature and discomfort but not skin temperature or heart rate, and reduced mean blood pressure (P = 0.046) during fixed-intensity exercise. Elevated humidity impaired time-trial performance by 3.4% (95% CI: ±2.2%; P = 0.006). In conclusion, these findings quantify the importance of absolute humidity alongside air temperature when exercising under severe heat stress.
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Affiliation(s)
- Elliott J. Jenkins
- School of Physical EducationSport and Exercise SciencesUniversity of OtagoDunedinNew Zealand
- Cardiff School of Sport and Health SciencesCardiff Metropolitan UniversityCardiffUK
| | - Holly A. Campbell
- Department of Surgical SciencesDunedin School of MedicineUniversity of OtagoDunedinNew Zealand
| | - Jason K. W. Lee
- Department of PhysiologyNational University of SingaporeSingapore
- Heat Resilience and Performance CentreYong Loo Lin School of MedicineNational University of SingaporeSingapore
- Human Potential Translational Research ProgrammeYong Loo Lin School of MedicineNational University of SingaporeSingapore
- Department of PhysiologyYong Loo Lin School of MedicineNational University of SingaporeSingapore
- Campus for Research Excellence and Technological Enterprise (CREATE)Singapore
| | - Toby Mündel
- School of SportExercise and NutritionMassey UniversityPalmerston NorthNew Zealand
| | - James D. Cotter
- School of Physical EducationSport and Exercise SciencesUniversity of OtagoDunedinNew Zealand
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Roxburgh BH, Cotter JD, Campbell HA, Reymann U, Wilson LC, Gwynne-Jones D, van Rij AM, Thomas KN. Physiological relationship between cardiorespiratory fitness and fitness for surgery: a narrative review. Br J Anaesth 2023; 130:122-132. [PMID: 36529576 DOI: 10.1016/j.bja.2022.10.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 10/11/2022] [Accepted: 10/24/2022] [Indexed: 12/23/2022] Open
Abstract
Epidemiological evidence has highlighted a strong relationship between cardiorespiratory fitness and surgical outcomes; specifically, fitter patients possess heightened resilience to withstand the surgical stress response. This narrative review draws on exercise and surgical physiology research to discuss and hypothesise the potential mechanisms by which higher fitness affords perioperative benefit. A higher fitness, as indicated by higher peak rate of oxygen consumption and ability to sustain metabolic homeostasis (i.e. higher anaerobic threshold) is beneficial postoperatively when metabolic demands are increased. However, the associated adaptations with higher fitness, and the related participation in regular exercise or physical activity, might also underpin the observed perioperative benefit through a process of hormesis, a protective adaptive response to the moderate and intermittent stress of exercise. Potential mediators discussed include greater antioxidant capacity, metabolic flexibility, glycaemic control, lean body mass, and improved mood.
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Affiliation(s)
- Brendon H Roxburgh
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand; School of Physical Education, Sport and Exercise Sciences, Dunedin, University of Otago, New Zealand.
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, Dunedin, University of Otago, New Zealand
| | - Holly A Campbell
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Ulla Reymann
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Luke C Wilson
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - David Gwynne-Jones
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand; Department of Orthopaedic Surgery, Southern District Health Board, Dunedin, New Zealand
| | - Andre M van Rij
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Kate N Thomas
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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Gibbons TD, Cotter JD, Ainslie PN, Abraham WC, Mockett BG, Campbell HA, Jones EMW, Jenkins EJ, Thomas KN. Fasting for 20 h does not affect exercise-induced increases in circulating BDNF in humans. J Physiol 2023. [PMID: 36631068 DOI: 10.1113/jp283582] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 11/18/2022] [Indexed: 01/13/2023] Open
Abstract
Intermittent fasting and exercise provide neuroprotection from age-related cognitive decline. A link between these two seemingly distinct stressors is their capability to steer the brain away from exclusively glucose metabolism. This cerebral substrate switch has been implicated in upregulating brain-derived neurotrophic factor (BDNF), a protein involved in neuroplasticity, learning and memory, and may underlie some of these neuroprotective effects. We examined the isolated and interactive effects of (1) 20-h fasting, (2) 90-min light exercise, and (3) high-intensity exercise on peripheral venous BDNF in 12 human volunteers. A follow-up study isolated the influence of cerebrovascular shear stress on circulating BDNF. Fasting for 20 h decreased glucose and increased ketones (P ≤ 0.0157) but had no effect on BDNF (P ≥ 0.4637). Light cycling at 25% of peak oxygen uptake ( V ̇ O 2 peak ${\dot V_{{{\rm{O}}_{\rm{2}}}{\rm{peak}}}}$ ) increased serum BDNF by 6 ± 8% (independent of being fed or fasted) and was mediated by a 7 ± 6% increase in platelets (P < 0.0001). Plasma BDNF was increased from 336 pg l-1 [46,626] to 390 pg l-1 [127,653] by 90-min of light cycling (P = 0.0128). Six 40-s intervals at 100% of V ̇ O 2 peak ${\dot V_{{{\rm{O}}_{\rm{2}}}{\rm{peak}}}}$ increased plasma and serum BDNF, as well as the BDNF-per-platelet ratio 4- to 5-fold more than light exercise did (P ≤ 0.0044). Plasma BDNF was correlated with circulating lactate during the high-intensity intervals (r = 0.47, P = 0.0057), but not during light exercise (P = 0.7407). Changes in cerebral shear stress - whether occurring naturally during exercise or induced experimentally with inspired CO2 - did not correspond with changes in BDNF (P ≥ 0.2730). BDNF responses to low-intensity exercise are mediated by increased circulating platelets, and increasing either exercise duration or particularly intensity is required to liberate free BDNF. KEY POINTS: Intermittent fasting and exercise both have potent neuroprotective effects and an acute upregulation of brain-derived neurotrophic factor (BDNF) appears to be a common mechanistic link. Switching the brain's fuel source from glucose to either ketone bodies or lactate, i.e. a cerebral substrate switch, has been shown to promote BDNF production in the rodent brain. Fasting for 20 h caused a 9-fold increase in ketone body delivery to the brain but had no effect on any metric of BDNF in peripheral circulation at rest. Prolonged (90 min) light cycling exercise increased plasma- and serum-derived BDNF irrespective of being fed or fasted and seemed to be independent of changes in cerebral shear stress. Six minutes of high-intensity cycling intervals increased every metric of circulating BDNF by 4 to 5 times more than prolonged low-intensity cycling; the increase in plasma-derived BDNF was correlated with a 6-fold increase in circulating lactate irrespective of feeding or fasting. Compared to 1 day of fasting with or without prolonged light exercise, high-intensity exercise is a much more efficient means to increase BDNF in circulation.
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Affiliation(s)
- Travis D Gibbons
- School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand.,Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan, School of Health and Exercise Science, Kelowna, British Columbia, Canada
| | - James D Cotter
- School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan, School of Health and Exercise Science, Kelowna, British Columbia, Canada
| | - Wickliffe C Abraham
- Department of Psychology, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Bruce G Mockett
- Department of Psychology, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Holly A Campbell
- Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - Emma M W Jones
- School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand.,Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - Elliott J Jenkins
- School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand.,Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Kate N Thomas
- Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
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Gibbons TD, Dempsey JA, Thomas KN, Ainslie PN, Wilson LC, Stothers TAM, Campbell HA, Cotter JD. Carotid body hyperexcitability underlies heat-induced hyperventilation in exercising humans. J Appl Physiol (1985) 2022; 133:1394-1406. [PMID: 36302157 DOI: 10.1152/japplphysiol.00435.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Physical activity is the most common source of heat strain for humans. The thermal strain of physical activity causes overbreathing (hyperventilation) and this has adverse physiological repercussions. The mechanisms underlying heat-induced hyperventilation during exercise are unknown, but recent evidence supports a primary role of carotid body hyperexcitability (increased tonic activity and sensitivity) underpinning hyperventilation in passively heated humans. In a repeated-measures crossover design, 12 healthy participants (6 female) completed two low-intensity cycling exercise conditions (25% maximal aerobic power) in randomized order, one with core temperature (TC) kept relatively stable near thermoneutrality, and the other with progressive heat strain to +2°C TC. To provide a complete examination of carotid body function under graded heat strain, carotid body tonic activity was assessed indirectly by transient hyperoxia, and its sensitivity estimated by responses to both isocapnic and poikilocapnic hypoxia. Carotid body tonic activity was increased by 220 ± 110% during cycling alone, and by 400 ± 290% with supplemental thermal strain to +1°C TC, and 600 ± 290% at +2°C TC (interaction, P = 0.0031). During exercise with heat stress at both +1°C and +2°C TC, carotid body suppression by hyperoxia decreased ventilation below the rates observed during exercise without heat stress (P < 0.0147). Carotid body sensitivity was increased by up to 230 ± 190% with exercise alone, and by 290 ± 250% with supplemental heating to +1°C TC and 510 ± 470% at +2°C TC (interaction, P = 0.0012). These data indicate that the carotid body is further activated and sensitized by heat strain during exercise and this largely explains the added drive to breathe.NEW & NOTEWORTHY Physical activity is the most common way humans increase their core temperature, and excess breathing in the heat can limit heat tolerance and performance, and may increase the risk of heat-related injury. Dose-dependent increases in carotid body tonic activity and sensitivity with core heating provide compelling evidence that carotid body hyperexcitability is the primary cause of heat-induced hyperventilation during exercise.
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Affiliation(s)
- Travis D Gibbons
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan, School of Health and Exercise Science, Kelowna, British Columbia, Canada
| | - Jerome A Dempsey
- John Rankin Laboratory for Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Kate N Thomas
- Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan, School of Health and Exercise Science, Kelowna, British Columbia, Canada
| | - Luke C Wilson
- Department of Medicine, University of Otago, Dunedin, New Zealand
| | - Tiarna A M Stothers
- School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Holly A Campbell
- Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand
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11
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Gibbons TD, Dempsey JA, Thomas KN, Campbell HA, Stothers TAM, Wilson LC, Ainslie PN, Cotter JD. Contribution of the carotid body to thermally mediated hyperventilation in humans. J Physiol 2022; 600:3603-3624. [PMID: 35731687 DOI: 10.1113/jp282918] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 06/15/2022] [Indexed: 01/05/2023] Open
Abstract
Humans hyperventilate under heat and cold strain. This hyperventilatory response has detrimental consequences including acid-base dysregulation, dyspnoea, decreased cerebral blood flow and accelerated brain heating. The ventilatory response to hypoxia is exaggerated under whole-body heating and cooling, indicating that altered carotid body function might contribute to thermally mediated hyperventilation. To address whether the carotid body might contribute to heat- and cold-induced hyperventilation, we indirectly measured carotid body tonic activity via hyperoxia, and carotid body sensitivity via hypoxia, under graded heat and cold strain in 13 healthy participants in a repeated-measures design. We hypothesised that carotid body tonic activity and sensitivity would be elevated in a dose-dependent manner under graded heat and cold strain, thereby supporting its role in driving thermally mediated hyperventilation. Carotid body tonic activity was increased in a dose-dependent manner with heating, reaching 175% above baseline (P < 0.0005), and carotid body suppression with hyperoxia removed all of the heat-induced increase in ventilation (P = 0.9297). Core cooling increased carotid body activity by up to 250% (P < 0.0001), but maximal values were reached with mild cooling and thereafter plateaued. Carotid body sensitivity to hypoxia was profoundly increased by up to 180% with heat stress (P = 0.0097), whereas cooling had no detectable effect on hypoxic sensitivity. In summary, cold stress increased carotid body tonic activity and this effect was saturated with mild cooling, whereas heating had clear dose-dependent effects on carotid body tonic activity and sensitivity. These dose-dependent effects with heat strain indicate that the carotid body probably plays a primary role in driving heat-induced hyperventilation. KEY POINTS: Humans over-breathe (hyperventilate) when under heat and cold stress, and though this has detrimental physiological repercussions, the mechanisms underlying this response are unknown. The carotid body, a small organ that is responsible for driving hyperventilation in hypoxia, was assessed under incremental heat and cold strain. The carotid body drive to breathe, as indirectly assessed by transient hyperoxia, increased in a dose-dependent manner with heating, reaching 175% above baseline; cold stress similarly increased the carotid body drive to breathe, but did not show dose-dependency. Carotid body sensitivity, as indirectly assessed by hypoxic ventilatory responses, was profoundly increased by 70-180% with mild and severe heat strain, whereas cooling had no detectable effect. Carotid body hyperactivity and hypersensitivity are two interrelated mechanisms that probably underlie the increased drive to breathe with heat strain, whereas carotid body hyperactivity during mild cooling may play a subsidiary role in cold-induced hyperventilation.
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Affiliation(s)
- Travis D Gibbons
- School of Physical Education, Sport & Exercise Science, University of Otago, Dunedin, Otago, New Zealand.,Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Jerome A Dempsey
- John Rankin Laboratory for Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Kate N Thomas
- Department of Surgical Sciences, University of Otago, Dunedin, Otago, New Zealand
| | - Holly A Campbell
- Department of Surgical Sciences, University of Otago, Dunedin, Otago, New Zealand
| | - Tiarna A M Stothers
- School of Physical Education, Sport & Exercise Science, University of Otago, Dunedin, Otago, New Zealand
| | - Luke C Wilson
- Department of Medicine, University of Otago, Dunedin, Otago, New Zealand
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - James D Cotter
- School of Physical Education, Sport & Exercise Science, University of Otago, Dunedin, Otago, New Zealand
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12
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Thomas KN, Gibbons TD, Campbell HA, Cotter JD, van Rij AM. Pulsatile flow in venous perforators of the lower limb. Am J Physiol Regul Integr Comp Physiol 2022; 323:R59-R67. [PMID: 35503236 DOI: 10.1152/ajpregu.00013.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Teaching traditionally asserts that the arterial pressure pulse is dampened across the capillary bed to the extent that pulsatility is non-existent in the venous circulation of the lower limbs. Herein, we present evidence of transmission of arterial pulsations across the capillary network into perforator veins in the lower limbs of healthy, heat-stressed humans. Perforator veins are connections from the superficial veins that drain into the deep veins. When assessed using ultrasound at rest, they infrequently demonstrate flow and a pulsatile flow waveform is not described. We investigated perforator vein pulsatility in ten young, healthy volunteers who underwent passive heating by +2 ºC deep body temperature via a hot-water-perfused suit, and five who also underwent active heating by +2 ºC via low-intensity cycling while wearing the hot-water-perfused suit. At +0.5 ºC increments in temperature, blood velocity in an ankle perforator vein was measured using duplex ultrasound. In all perforators with heating, sustained flow was demonstrated, with a pulsatile waveform that was synchronous with the cardiac cycle. The maximum velocity was 29 ± 14 cm/s with passive heating and approximately half with active heating (P=0.04). The small veins of the skin at the ankle also demonstrated increased perfusion with pulsatility, seen with low-velocity microvascular imaging technology. We consider explanations for this pulsatility and conclude that it is propagated from the arterial inflow through the skin microcirculation as a result of increased dilatation and flow volume, and that this a normal response to increased skin blood flow.
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Affiliation(s)
- Kate N Thomas
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Travis D Gibbons
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.,School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand.,Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan, School of Health and Exercise Science, Kelowna, British Columbia, Canada
| | - Holly A Campbell
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Andre Marie van Rij
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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13
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Campbell HA, Akerman AP, Kissling LS, Prout JR, Gibbons TD, Thomas KN, Cotter JD. Acute physiological and psychophysical responses to different modes of heat stress. Exp Physiol 2022; 107:429-440. [PMID: 35193165 PMCID: PMC9314810 DOI: 10.1113/ep089992] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 02/14/2022] [Indexed: 11/16/2022]
Abstract
New Findings What is the central question of this study? What are the profiles of acute physiological and psychophysical strain during and in recovery from different modes of heating, and to what extent do these diminish after repeated exposure? What is the main finding and its importance? Mode of heating affects the strain profiles during heat stress and recovery. Exercise in the heat incurred the greatest cardiovascular strain during heating and recovery. Humid heat was poorly tolerated despite heat strain being no greater than in other heating modes, and tolerance did not improve with multiple exposures.
Abstract Heat stress is common and arises endogenously and exogenously. It can be acutely hazardous while also increasingly advocated to drive health and performance‐related adaptations. Yet, the nature of strain (deviation in regulated variables) imposed by different heating modes is not well established, despite the potential for important differences. We, therefore, compared three modes of heat stress for thermal, cardiovascular and perceptual strain profiles during exposure and recovery when experienced as a novel stimulus and an accustomed stimulus. In a crossover design, 13 physically active participants (five females) underwent 5 days of 60‐min exposures to hot water immersion (40°C), sauna (55°C, 54% relative humidity) and exercise in the heat (40°C, 52% relative humidity), and a thermoneutral water immersion control (36.5°C), each separated by ≥4 weeks. Physiological (thermal, cardiovascular, haemodynamic) and psychophysical strain responses were assessed on days 1 and 5. Sauna evoked the warmest skin (40°C; P < 0.001) but exercise in the heat caused the largest increase in core temperature, sweat rate, heart rate (post hoc comparisons all P < 0.001) and systolic blood pressure (P ≤ 0.002), and possibly decrease in diastolic blood pressures (P ≤ 0.130), regardless of day. Thermal sensation and feeling state were more favourable on day 5 than on day 1 (P ≤ 0.021), with all modes of heat being equivalently uncomfortable (P ≥ 0.215). Plasma volume expanded the largest extent during immersions (P < 0.001). The current data highlight that exercising in the heat generates a more complex strain profile, while passive heat stress in humid heat has lower tolerance and more cardiovascular strain than hot water immersion.
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Affiliation(s)
- Holly A Campbell
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand.,Department of Surgical Sciences, Otago Medical School, University of Otago, Dunedin, New Zealand
| | - Ashley P Akerman
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand.,Department of Surgical Sciences, Otago Medical School, University of Otago, Dunedin, New Zealand.,Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ontario, Canada
| | - Lorenz S Kissling
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Jamie R Prout
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Travis D Gibbons
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand.,Department of Surgical Sciences, Otago Medical School, University of Otago, Dunedin, New Zealand
| | - Kate N Thomas
- Department of Surgical Sciences, Otago Medical School, University of Otago, Dunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
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14
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Kissling LS, Akerman AP, Campbell HA, Prout JR, Gibbons TD, Thomas KN, Cotter JD. A crossover control study of three methods of heat acclimation on the magnitude and kinetics of adaptation. Exp Physiol 2021; 107:337-349. [PMID: 34957632 DOI: 10.1113/ep089993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 12/22/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS Central question to the study? Are primary indices of heat adaptation (e.g., expansion of plasma volume and reduction in resting core temperature) differentially affected by the three major modes of short-term heat acclimation, i.e., exercise in the heat, hot water immersion and sauna? Main finding and its importance? The three modes elicited typical adaptations expected with short-term heat acclimation, however these were not significantly different between modes. This comparison has not previously been done and highlights that individuals can expect similar adaptation to heat regardless of the mode used. ABSTRACT Heat acclimation (HA) can improve heat tolerance and cardiovascular health. The mode of HA potentially impacts the magnitude and time course of adaptations, but almost no comparative data exist. We therefore investigated adaptive responses to three common modes of HA, particularly with respect to plasma volume. Within a crossover repeated-measures design, 13 physically-active participants (5 female) undertook four, 5-d HA regimes (60 min/d) in randomised order, separated by ≥4 wk. Rectal temperature (Tre ) was clamped at neutrality via 36.6C (thermoneutral) water immersion (TWI; i.e., control condition), or raised by 1.5°C via heat stress in 40°C water (HWI), Sauna (55°C, 52% RH), or exercise in humid heat (40°C, 52% RH; ExH). Adaptation magnitude was assessed as the pooled response across days 4 to 6, while kinetics was assessed via the 6-d time series. Plasma volume expansion was similar in all heated conditions but only higher than TWI in ExH (by 4%, p = 0.036). Approximately two thirds of the expansion was attained within the initial 24 h and was moderately related to that present on day 6, regardless of HA mode (r = 0.560-0.887). Expansion was mediated by conservation of both sodium and albumin content, with little evidence for these having differential roles between modes (p = 0.706 and 0.320, respectively). Resting Tre decreased by 0.1-0.3°C in all heated conditions, and SBP decreased by 4 mm Hg, but not differentially between conditions (p≥0.137). In conclusion, HA mode did not substantially affect the magnitude or rate of adaptation in key resting markers of short-term HA. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Lorenz S Kissling
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Ashley P Akerman
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand.,Department of Surgical Sciences, Department of Medicine, University of Otago, Dunedin, New Zealand
| | - Holly A Campbell
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand.,Department of Surgical Sciences, Department of Medicine, University of Otago, Dunedin, New Zealand
| | - Jamie R Prout
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Travis D Gibbons
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand.,Department of Surgical Sciences, Department of Medicine, University of Otago, Dunedin, New Zealand
| | - Kate N Thomas
- Department of Surgical Sciences, Department of Medicine, University of Otago, Dunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
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15
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Russell BM, Chang CR, Hill T, Cotter JD, Francois ME. Post-exercise Warm or Cold Water Immersion to Augment the Cardiometabolic Benefits of Exercise Training: A Proof of Concept Trial. Front Physiol 2021; 12:759240. [PMID: 34803740 PMCID: PMC8595200 DOI: 10.3389/fphys.2021.759240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/05/2021] [Indexed: 11/29/2022] Open
Abstract
We investigated whether substituting the final half within 60-min bouts of exercise with passive warm or cold water immersion would provide similar or greater benefits for cardiometabolic health. Thirty healthy participants were randomized to two of three short-term training interventions in a partial crossover (12 sessions over 14–16 days, 4 week washout): (i) EXS: 60 min cycling 70% maximum heart rate (HRmax), (ii) WWI: 30 min cycling then 30 min warm water (38–40°C) immersion, and/or (iii) CWI: 30 min cycling then 30 min cold water (10–12°C) immersion. Before and after, participants completed a 20 min cycle work trial, V.O2max test, and an Oral Glucose Tolerance Test during which indirect calorimetry was used to measure substrate oxidation and metabolic flexibility (slope of fasting to post-prandial carbohydrate oxidation). Data from twenty two participants (25 ± 5 year, BMI 23 ± 3 kg/m2, Female = 11) were analyzed using a fixed-effects linear mixed model. V.O2max increased more in EXS (interaction p = 0.004) than CWI (95% CI: 1.1, 5.3 mL/kg/min, Cohen’s d = 1.35), but not WWI (CI: −0.4, 3.9 mL/kg/min, d = 0.72). Work trial distance and power increased 383 ± 223 m and 20 ± 6 W, respectively, without differences between interventions (interaction both p > 0.68). WWI lowered post-prandial glucose ∼9% (CI −1.9, −0.5 mmol/L; d = 0.63), with no difference between interventions (interaction p = 0.469). Substituting the second half of exercise with WWI provides similar cardiometabolic health benefits to time matched exercise, however, substituting with CWI does not.
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Affiliation(s)
- Brooke M Russell
- School of Medicine, University of Wollongong, Wollongong, NSW, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
| | - Courtney R Chang
- School of Medicine, University of Wollongong, Wollongong, NSW, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
| | - Terry Hill
- School of Medicine, University of Wollongong, Wollongong, NSW, Australia
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Monique E Francois
- School of Medicine, University of Wollongong, Wollongong, NSW, Australia.,Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
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16
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Peddie MC, Kessell C, Bergen T, Gibbons TD, Campbell HA, Cotter JD, Rehrer NJ, Thomas KN. The effects of prolonged sitting, prolonged standing, and activity breaks on vascular function, and postprandial glucose and insulin responses: A randomised crossover trial. PLoS One 2021; 16:e0244841. [PMID: 33395691 PMCID: PMC7781669 DOI: 10.1371/journal.pone.0244841] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 12/16/2020] [Indexed: 12/26/2022] Open
Abstract
The objective of this study was to compare acute effects of prolonged sitting, prolonged standing and sitting interrupted with regular activity breaks on vascular function and postprandial glucose metabolism. In a randomized cross-over trial, 18 adults completed: 1. Prolonged Sitting; 2. Prolonged Standing and 3. Sitting with 2-min walking (5 km/h, 10% incline) every 30 min (Regular Activity Breaks). Flow mediated dilation (FMD) was measured in the popliteal artery at baseline and 6 h. Popliteal artery hemodynamics, and postprandial plasma glucose and insulin were measured over 6 h. Neither raw nor allometrically-scaled FMD showed an intervention effect (p = 0.285 and 0.159 respectively). Compared to Prolonged Sitting, Regular Activity Breaks increased blood flow (overall effect of intervention p<0.001; difference = 80%; 95% CI 34 to 125%; p = 0.001) and net shear rate (overall effect of intervention p<0.001; difference = 72%; 95% CI 30 to 114%; p = 0.001) at 60 min. These differences were then maintained for the entire 6 h. Prolonged Standing increased blood flow at 60 min only (overall effect of intervention p<0.001; difference = 62%; 95% CI 28 to 97%; p = 0.001). Regular Activity Breaks decreased insulin incremental area under the curve (iAUC) when compared to both Prolonged Sitting (overall effect of intervention P = 0.001; difference = 28%; 95% CI 14 to 38%; p<0.01) and Prolonged Standing (difference = 19%; 95% CI 4 to 32%, p = 0.015). There was no intervention effect on glucose iAUC or total AUC (p = 0.254 and 0.450, respectively). In normal-weight participants, Regular Activity Breaks induce increases in blood flow, shear stress and improvements in postprandial metabolism that are associated with beneficial adaptations. Physical activity and sedentary behaviour messages should perhaps focus more on the importance of frequent movement rather than simply replacing sitting with standing.
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Affiliation(s)
- Meredith C. Peddie
- Department of Human Nutrition, University of Otago, Dunedin, New Zealand
| | - Chris Kessell
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Tom Bergen
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Travis D. Gibbons
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Holly A. Campbell
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - James D. Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Nancy J. Rehrer
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Kate N. Thomas
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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17
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Thomas KN, Kissling LS, Gibbons TD, Akerman AP, Rij AM, Cotter JD. The acute effect of resistance exercise on limb blood flow. Exp Physiol 2020; 105:2099-2109. [DOI: 10.1113/ep088743] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 10/12/2020] [Indexed: 12/16/2022]
Affiliation(s)
- Kate N. Thomas
- Department of Surgical Sciences Dunedin School of Medicine University of Otago Dunedin New Zealand
| | - Lorenz S. Kissling
- School of Physical Education Sport and Exercise Sciences University of Otago Dunedin New Zealand
| | - Travis D. Gibbons
- School of Physical Education Sport and Exercise Sciences University of Otago Dunedin New Zealand
| | - Ashley P. Akerman
- School of Physical Education Sport and Exercise Sciences University of Otago Dunedin New Zealand
- Human and Environmental Physiology Research Unit University of Ottawa Ottawa Ontario Canada
| | - Andre M. Rij
- Department of Surgical Sciences Dunedin School of Medicine University of Otago Dunedin New Zealand
| | - James D. Cotter
- School of Physical Education Sport and Exercise Sciences University of Otago Dunedin New Zealand
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18
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Casadio JR, Wiseman D, Kilding AE, Cotter JD, Laursen PB. Heat Training Improves Cardiovascular Responses And Briefly Blunts Sprint Performance In Elite Sprint Track Cyclists. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000679640.15724.fc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Roxburgh BH, Campbell HA, Cotter JD, Reymann U, Williams MJA, Gwynne-Jones D, Thomas KN. Cardiopulmonary exercise testing in severe osteoarthritis: a crossover comparison of four exercise modalities. Anaesthesia 2020; 76:72-81. [PMID: 32592218 DOI: 10.1111/anae.15162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 05/24/2020] [Indexed: 12/01/2022]
Abstract
Cardiopulmonary exercise testing is performed increasingly for cardiorespiratory fitness assessment and pre-operative risk stratification. Lower limb osteoarthritis is a common comorbidity in surgical patients, meaning traditional cycle ergometry-based cardiopulmonary exercise testing is difficult. The purpose of this study was to compare cardiopulmonary exercise testing variables and subjective responses in four different exercise modalities. In this crossover study, 15 patients with osteoarthritis scheduled for total hip or knee arthroplasty (mean (SD) age 68 (7) years; body mass index 31.4 (4.1) kg.m-2 ) completed cardiopulmonary exercise testing on a treadmill, elliptical cross-trainer, cycle and arm ergometer. Mean (SD) peak oxygen consumption was 20-30% greater on the lower limb modalities (treadmill 21.5 (4.6) (p < 0.001); elliptical cross-trainer (21.2 (4.1) (p < 0.001); and cycle ergometer (19.4 (4.2) ml.min-1 .kg-1 (p = 0.001), respectively) than on the arm ergometer (15.7 (3.7) ml.min-1 .kg-1 ). Anaerobic threshold was 25-50% greater on the lower limb modalities (treadmill 13.5 (3.1) (p < 0.001); elliptical cross-trainer 14.6 (3.0) (p < 0.001); and cycle ergometer 10.7 (2.9) (p = 0.003)) compared with the arm ergometer (8.4 (1.7) ml.min-1 .kg-1 ). The median (95%CI) difference between pre-exercise and peak-exercise pain scores was greater for tests on the treadmill (2.0 (0.0-5.0) (p = 0.001); elliptical cross-trainer (3.0 (2.0-4.0) (p = 0.001); and cycle ergometer (3.0 (1.0-5.0) (p = 0.001)), compared with the arm ergometer (0.0 (0.0-1.0) (p = 0.406)). Despite greater peak exercise pain, cardiopulmonary exercise testing modalities utilising the lower limbs affected by osteoarthritis elicited higher peak oxygen consumption and anaerobic threshold values compared with arm ergometry.
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Affiliation(s)
- B H Roxburgh
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.,School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - H A Campbell
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - J D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - U Reymann
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - M J A Williams
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - D Gwynne-Jones
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - K N Thomas
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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Calverley TA, Ogoh S, Marley CJ, Steggall M, Marchi N, Brassard P, Lucas SJE, Cotter JD, Roig M, Ainslie PN, Wisløff U, Bailey DM. HIITing the brain with exercise: mechanisms, consequences and practical recommendations. J Physiol 2020; 598:2513-2530. [PMID: 32347544 DOI: 10.1113/jp275021] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 04/15/2020] [Indexed: 01/30/2023] Open
Abstract
The increasing number of older adults has seen a corresponding growth in those affected by neurovascular diseases, including stroke and dementia. Since cures are currently unavailable, major efforts in improving brain health need to focus on prevention, with emphasis on modifiable risk factors such as promoting physical activity. Moderate-intensity continuous training (MICT) paradigms have been shown to confer vascular benefits translating into improved musculoskeletal, cardiopulmonary and cerebrovascular function. However, the time commitment associated with MICT is a potential barrier to participation, and high-intensity interval training (HIIT) has since emerged as a more time-efficient mode of exercise that can promote similar if not indeed superior improvements in cardiorespiratory fitness for a given training volume and further promote vascular adaptation. However, randomised controlled trials (RCTs) investigating the impact of HIIT on the brain are surprisingly limited. The present review outlines how the HIIT paradigm has evolved from a historical perspective and describes the established physiological changes including its mechanistic bases. Given the dearth of RCTs, the vascular benefits of MICT are discussed with a focus on the translational neuroprotective benefits including their mechanistic bases that could be further potentiated through HIIT. Safety implications are highlighted and components of an optimal HIIT intervention are discussed including practical recommendations. Finally, statistical effect sizes have been calculated to allow prospective research to be appropriately powered and optimise the potential for detecting treatment effects. Future RCTs that focus on the potential clinical benefits of HIIT are encouraged given the prevalence of cognitive decline in an ever-ageing population.
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Affiliation(s)
- Thomas A Calverley
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, UK
| | - Shigehiko Ogoh
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, UK.,Department of Biomedical Engineering, Faculty of Engineering, Toyo University, Saitama, Japan
| | - Christopher J Marley
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, UK
| | - Martin Steggall
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, UK
| | - Nicola Marchi
- Cerebrovascular and Glia Research Laboratory, Department of Neuroscience, Institute of Functional Genomics, Montpellier, France
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
| | - Samuel J E Lucas
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Marc Roig
- Faculty of Medicine, McGill University, Montreal, Canada
| | - Philip N Ainslie
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, UK.,Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan Campus, Kelowna, BC, Canada
| | - Ulrik Wisløff
- The Cardiac Exercise Research Group, Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.,School of Human Movement and Nutrition Science, University of Queensland, Queensland, Australia
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, UK
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21
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Shoemaker LN, Wilson LC, Lucas SJ, Machado L, Walker RJ, Cotter JD. Effect of Cerebral Blood Flow on Cognition across Healthy Adulthood. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.06931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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22
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Fowler MJ, Cotter JD, Knight BE, Sevick-Muraca EM, Sandberg DI, Sirianni RW. Intrathecal drug delivery in the era of nanomedicine. Adv Drug Deliv Rev 2020; 165-166:77-95. [PMID: 32142739 DOI: 10.1016/j.addr.2020.02.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 12/17/2019] [Accepted: 02/28/2020] [Indexed: 12/23/2022]
Abstract
Administration of substances directly into the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord is one approach that can circumvent the blood-brain barrier to enable drug delivery to the central nervous system (CNS). However, molecules that have been administered by intrathecal injection, which includes intraventricular, intracisternal, or lumbar locations, encounter new barriers within the subarachnoid space. These barriers include relatively high rates of turnover as CSF clears and potentially inadequate delivery to tissue or cellular targets. Nanomedicine could offer a solution. In contrast to the fate of freely administered drugs, nanomedicine systems can navigate the subarachnoid space to sustain delivery of therapeutic molecules, genes, and imaging agents within the CNS. Some evidence suggests that certain nanomedicine agents can reach the parenchyma following intrathecal administration. Here, we will address the preclinical and clinical use of intrathecal nanomedicine, including nanoparticles, microparticles, dendrimers, micelles, liposomes, polyplexes, and other colloidalal materials that function to alter the distribution of molecules in tissue. Our review forms a foundational understanding of drug delivery to the CSF that can be built upon to better engineer nanomedicine for intrathecal treatment of disease.
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Affiliation(s)
- M J Fowler
- Vivian L. Smith Department of Neurosurgery, McGovern Medical School/University of Texas Health Science Center at Houston, Houston, TX 77030, United States of America
| | - J D Cotter
- Vivian L. Smith Department of Neurosurgery, McGovern Medical School/University of Texas Health Science Center at Houston, Houston, TX 77030, United States of America
| | - B E Knight
- Vivian L. Smith Department of Neurosurgery, McGovern Medical School/University of Texas Health Science Center at Houston, Houston, TX 77030, United States of America
| | - E M Sevick-Muraca
- Brown Foundation Institute of Molecular Medicine, Center for Molecular Imaging, Houston, TX 77030, United States of America
| | - D I Sandberg
- Vivian L. Smith Department of Neurosurgery, McGovern Medical School/University of Texas Health Science Center at Houston, Houston, TX 77030, United States of America; Department of Pediatric Surgery, McGovern Medical School/University of Texas Health Science Center at Houston, Houston, TX 77030, United States of America; Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, United States of America
| | - R W Sirianni
- Vivian L. Smith Department of Neurosurgery, McGovern Medical School/University of Texas Health Science Center at Houston, Houston, TX 77030, United States of America.
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23
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Lei TH, Schlader ZJ, Che Muhamed AM, Zheng H, Stannard SR, Kondo N, Cotter JD, Mündel T. Differences in dry-bulb temperature do not influence moderate-duration exercise performance in warm environments when vapor pressure is equivalent. Eur J Appl Physiol 2020; 120:841-852. [PMID: 32072226 DOI: 10.1007/s00421-020-04322-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/11/2020] [Indexed: 10/25/2022]
Abstract
PURPOSE Recent studies have determined that ambient humidity plays a more important role in aerobic performance than dry-bulb temperature does in warm environments; however, no studies have kept humidity constant and independently manipulated temperature. Therefore, the purpose of this study was to determine the contribution of dry-bulb temperature, when vapor pressure was matched, on the thermoregulatory, perceptual and performance responses to a 30-min cycling work trial. METHODS Fourteen trained male cyclists (age: 32 ± 12 year; height: 178 ± 6 cm; mass: 76 ± 9 kg; [Formula: see text]: 59 ± 9 mL kg-1 min-1; body surface area: 1.93 ± 0.12 m2; peak power output: 393 ± 53 W) volunteered, and underwent 1 exercise bout in moderate heat (MOD: 34.9 ± 0.2 °C, 50.1 ± 1.1% relative humidity) and 1 in mild heat (MILD: 29.2 ± 0.2 °C, 69.4 ± 0.9% relative humidity) matched for vapor pressure (2.8 ± 0.1 kPa), with trials counterbalanced. RESULTS Despite a higher weighted mean skin temperature during MOD (36.3 ± 0.5 vs. 34.5 ± 0.6 °C, p < 0.01), none of rectal temperature (38.0 ± 0.3 vs. 37.9 ± 0.4 °C, p = 0.30), local sweat rate (1.0 ± 0.3 vs. 0.9 ± 0.4 mg cm-2 min-1, p = 0.28), cutaneous blood flow (283 ± 116 vs. 287 ± 105 PU, p = 0.90), mean power output (206 ± 37 vs. 205 ± 41 W, p = 0.87) or total work completed (371 ± 64 vs. 369 ± 70 kJ, p = 0.77) showed any difference between environments during the work trial. However, all perceptual measures (perceived exertion, thermal discomfort, thermal sensation, skin wettedness, pleasantness, all p < 0.05) were affected detrimentally during MOD compared to MILD. CONCLUSION In a warm and compensable environment, dry-bulb temperature did not influence high-intensity cycling performance when vapor pressure was maintained, whilst the perceptual responses were affected.
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Affiliation(s)
- Tze-Huan Lei
- School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, Kobe, Japan
| | - Zachary J Schlader
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, IN, USA
| | - Ahmad Munir Che Muhamed
- Lifestyle Science Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Penang, Malaysia
| | - Huixin Zheng
- School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand
| | - Stephen R Stannard
- School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand
| | - Narihiko Kondo
- Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, Kobe, Japan
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Toby Mündel
- School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand.
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24
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Gibbons TD, Tymko MM, Thomas KN, Wilson LC, Stembridge M, Caldwell HG, Howe CA, Hoiland RL, Akerman AP, Dawkins TG, Patrician A, Coombs GB, Gasho C, Stacey BS, Ainslie PN, Cotter JD. Global REACH 2018: The influence of acute and chronic hypoxia on cerebral haemodynamics and related functional outcomes during cold and heat stress. J Physiol 2020; 598:265-284. [PMID: 31696936 DOI: 10.1113/jp278917] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 10/28/2019] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Thermal and hypoxic stress commonly coexist in environmental, occupational and clinical settings, yet how the brain tolerates these multi-stressor environments is unknown Core cooling by 1.0°C reduced cerebral blood flow (CBF) by 20-30% and cerebral oxygen delivery (CDO2 ) by 12-19% at sea level and high altitude, whereas core heating by 1.5°C did not reliably reduce CBF or CDO2 Oxygen content in arterial blood was fully restored with acclimatisation to 4330 m, but concurrent cold stress reduced CBF and CDO2 Gross indices of cognition were not impaired by any combination of thermal and hypoxic stress despite large reductions in CDO2 Chronic hypoxia renders the brain susceptible to large reductions in oxygen delivery with concurrent cold stress, which might make monitoring core temperature more important in this context ABSTRACT: Real-world settings are composed of multiple environmental stressors, yet the majority of research in environmental physiology investigates these stressors in isolation. The brain is central in both behavioural and physiological responses to threatening stimuli and, given its tight metabolic and haemodynamic requirements, is particularly susceptible to environmental stress. We measured cerebral blood flow (CBF, duplex ultrasound), cerebral oxygen delivery (CDO2 ), oesophageal temperature, and arterial blood gases during exposure to three commonly experienced environmental stressors - heat, cold and hypoxia - in isolation, and in combination. Twelve healthy male subjects (27 ± 11 years) underwent core cooling by 1.0°C and core heating by 1.5°C in randomised order at sea level; acute hypoxia ( P ET , O 2 = 50 mm Hg) was imposed at baseline and at each thermal extreme. Core cooling and heating protocols were repeated after 16 ± 4 days residing at 4330 m to investigate any interactions with high altitude acclimatisation. Cold stress decreased CBF by 20-30% and CDO2 by 12-19% (both P < 0.01) irrespective of altitude, whereas heating did not reliably change either CBF or CDO2 (both P > 0.08). The increases in CBF with acute hypoxia during thermal stress were appropriate to maintain CDO2 at normothermic, normoxic values. Reaction time was faster and slower by 6-9% with heating and cooling, respectively (both P < 0.01), but central (brain) processes were not impaired by any combination of environmental stressors. These findings highlight the powerful influence of core cooling in reducing CDO2 . Despite these large reductions in CDO2 with cold stress, gross indices of cognition remained stable.
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Affiliation(s)
- T D Gibbons
- School of Physical Education, Sport & Exercise Science, University of Otago, 55/47 Union St W, Dunedin, 9016, New Zealand
| | - M M Tymko
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - K N Thomas
- Department of Surgical Sciences, University of Otago, 201 Great King St, Dunedin, 9016, New Zealand
| | - L C Wilson
- Department of Medicine, University of Otago, 201 Great King St, Dunedin, 9016, New Zealand
| | - M Stembridge
- Cardiff Centre for Exercise and Health, Cardiff Metropolitan University, Cyncoed Road, Cardiff, CF23 6XD, UK
| | - H G Caldwell
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - C A Howe
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - R L Hoiland
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - A P Akerman
- Faculty of Health Sciences, University of Ottawa, 125 University St, Ottawa, Ontario, Canada, K1N 6N5
| | - T G Dawkins
- Cardiff Centre for Exercise and Health, Cardiff Metropolitan University, Cyncoed Road, Cardiff, CF23 6XD, UK
| | - A Patrician
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - G B Coombs
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - C Gasho
- Division of Pulmonary, Critical Care, Hyperbaric and Sleep Medicine, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - B S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, UK
| | - P N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan Campus, School of Health and Exercise Sciences, 3333 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - J D Cotter
- School of Physical Education, Sport & Exercise Science, University of Otago, 55/47 Union St W, Dunedin, 9016, New Zealand
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25
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Perry BG, Cotter JD, Korad S, Lark S, Labrecque L, Brassard P, Paquette M, Le Blanc O, Lucas SJE. Implications of habitual endurance and resistance exercise for dynamic cerebral autoregulation. Exp Physiol 2019; 104:1780-1789. [DOI: 10.1113/ep087675] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 09/23/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Blake G. Perry
- School of Health SciencesMassey University Wellington New Zealand
- School of Sport, Exercise and NutritionMassey University Wellington New Zealand
| | - James D. Cotter
- School of Physical EducationSport and Exercise SciencesUniversity of Otago Dunedin New Zealand
| | - Stephanie Korad
- School of Sport, Exercise and NutritionMassey University Wellington New Zealand
| | - Sally Lark
- School of Sport, Exercise and NutritionMassey University Wellington New Zealand
| | - Lawrence Labrecque
- Department of KinesiologyFaculty of MedicineLaval University Quebec Canada
- Research center of the Institut universitaire de cardiologie et de pneumologie de Québec Quebec Canada
| | - Patrice Brassard
- Department of KinesiologyFaculty of MedicineLaval University Quebec Canada
- Research center of the Institut universitaire de cardiologie et de pneumologie de Québec Quebec Canada
| | - Myriam Paquette
- Department of KinesiologyFaculty of MedicineLaval University Quebec Canada
- Research center of the Institut universitaire de cardiologie et de pneumologie de Québec Quebec Canada
| | - Olivier Le Blanc
- Department of KinesiologyFaculty of MedicineLaval University Quebec Canada
- Research center of the Institut universitaire de cardiologie et de pneumologie de Québec Quebec Canada
| | - Samuel J. E. Lucas
- Department of PhysiologyUniversity of Otago Dunedin New Zealand
- School of Sport, Exercise and Rehabilitation Sciences & Centre for Human Brain HealthUniversity of Birmingham Birmingham UK
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26
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Shoemaker LN, Wilson LC, Lucas SJE, Machado L, Cotter JD. Cerebrovascular regulation is not blunted during mental stress. Exp Physiol 2019; 104:1678-1687. [PMID: 31465595 DOI: 10.1113/ep087832] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 08/22/2019] [Indexed: 01/08/2023]
Abstract
NEW FINDINGS What is the central question of the study? What are the effects of acute mental stress on the mechanisms regulating cerebral blood flow? What is the main finding and its importance? The major new findings are as follows: (i) high mental stress and hypercapnia had an interactive effect on mean middle cerebral artery blood velocity; (ii) high mental stress altered the regulation of cerebral blood flow; (iii) the increased cerebrovascular hypercapnic reactivity was not driven by changes in mean arterial pressure alone; and (iv) this increased perfusion with mental stress appeared not to be justified functionally by an increase in oxygen demand (as determined by near-infrared spectroscopy-derived measures). ABSTRACT In this study, we examined the effects of acute mental stress on cerebrovascular function. Sixteen participants (aged 23 ± 4 years; five female) were exposed to low and high mental stress using simple arithmetic (counting backwards from 1000) and more complex arithmetic (serial subtraction of 13 from a rapidly changing four-digit number), respectively. During consecutive conditions of baseline, low stress and high stress, end-tidal partial pressure of CO2 ( P ET , C O 2 ) was recorded at normocapnia (37 ± 3 mmHg) and clamped at two elevated levels (P < 0.01): 41 ± 1 and 46 ± 1 mmHg. Mean right middle cerebral artery blood velocity (MCAvmean ; transcranial Doppler ultrasound), right prefrontal cortex haemodynamics (near-infrared spectroscopy) and mean arterial blood pressure (MAP; finger photoplethysmography) were measured continuously. Cerebrovascular hypercapnic reactivity (ΔMCAvmean /Δ P ET , C O 2 ), cerebrovascular conductance (CVC; MCAvmean /MAP), CVC CO2 reactivity (ΔCVC/Δ P ET , C O 2 ) and total peripheral resistance (MAP/cardiac output) were calculated. Acute high mental stress increased MCAvmean by 7 ± 7%, and more so at higher P ET , C O 2 (32 ± 10%; interaction, P = 0.03), illustrating increased sensitivity to CO2 (i.e. its major regulator). High mental stress also increased MAP (17 ± 9%; P ≤ 0.01), coinciding with increased near-infrared spectroscopy-derived prefrontal haemoglobin volume and saturation measures. High mental stress elevated both cerebrovascular hypercapnic and conductance reactivities (main effect of stress, P ≤ 0.04). These findings indicate that the cerebrovascular response to acute high mental stress results in a coordinated regulation between multiple processes.
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Affiliation(s)
- Leena N Shoemaker
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Luke C Wilson
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Samuel J E Lucas
- Department of Physiology, University of Otago, Dunedin, New Zealand.,School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK.,Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| | - Liana Machado
- Department of Psychology, University of Otago, Dunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
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27
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Shoemaker LN, Wilson LC, Lucas SJE, Machado L, Thomas KN, Cotter JD. Swimming-related effects on cerebrovascular and cognitive function. Physiol Rep 2019; 7:e14247. [PMID: 31637867 PMCID: PMC6803778 DOI: 10.14814/phy2.14247] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 09/06/2019] [Indexed: 02/07/2023] Open
Abstract
Both acute and regular exercise influence vascular and cognitive function. Upright aquatic exercise increases mean middle cerebral artery blood velocity (MCAvmean ) and has been suggested as favorable for cerebrovascular adaptations. However, MCAvmean has not been reported during swimming. Thus, we examined the cerebrovascular and cognitive effects of swimming. Ten land-based athletes (22 ± 5 years) and eight swimmers (19 ± 1 years) completed three cognitive tasks and four conditions that were used to independently and collectively delineate the swimming-related factors (i.e., posture, immersion, CO2 retention [end-tidal CO2 ; PETCO2 ], and motor involvement). Measurements of MCAvmean and PETCO2 were taken throughout each condition. Prone posture increased MCAvmean by 11% (P < 0.01 vs. upright land). Water immersion independently increased MCAvmean when upright (12%; P < 0.01) but not prone (P = 0.76). The consequent rise in PETCO2 during head-out, breast-stroke swimming (50% heart rate range) independently increased MCAvmean by 14% (P < 0.01), while the motor involvement of swimming per se did not significantly change MCAvmean (P = 0.32). While accounting for sex, swimmers had ~17% lower MCAvmean during all rest conditions (P ≤ 0.05). However, in a subset of participants, both groups had similar internal carotid artery diameters (P = 0.99) and velocities (P = 0.97). Water immersion per se did not alter cognition (P ≥ 0.15), but 20 min of moderate-intensity swimming improved visuomotor performance by 4% (P = 0.03), regardless of athlete group (P = 0.12). In conclusion, breast-stroke swimming increased MCAvmean mostly due to postural and PETCO2 effects, with minimal contributions from water immersion or motor activity. Lastly, swimming improved cognitive functioning acutely, regardless of athlete group. Future research should explore the chronic effects of swimming on cerebrovascular function and cognition, particularly in aging.
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Affiliation(s)
- Leena N. Shoemaker
- School of Physical Education, Sport and Exercise SciencesUniversity of OtagoDunedinNew Zealand
- Department of MedicineDunedin School of MedicineUniversity of OtagoDunedinNew Zealand
- Department of PsychologyUniversity of OtagoDunedinNew Zealand
| | - Luke C. Wilson
- Department of MedicineDunedin School of MedicineUniversity of OtagoDunedinNew Zealand
| | - Samuel J. E. Lucas
- Department of PhysiologyUniversity of OtagoDunedinNew Zealand
- School of Sport, Exercise and Rehabilitation SciencesCollege of Life and Environmental SciencesUniversity of BirminghamBirminghamUK
- Centre for Human Brain HealthUniversity of BirminghamBirminghamUK
| | - Liana Machado
- Department of PsychologyUniversity of OtagoDunedinNew Zealand
| | - Kate N. Thomas
- Department of Surgical SciencesDunedin School of MedicineUniversity of OtagoDunedinNew Zealand
| | - James D. Cotter
- School of Physical Education, Sport and Exercise SciencesUniversity of OtagoDunedinNew Zealand
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28
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Kissling LS, Akerman AP, Cotter JD. Heat-induced hypervolemia: Does the mode of acclimation matter and what are the implications for performance at Tokyo 2020? Temperature (Austin) 2019; 7:129-148. [PMID: 33015241 DOI: 10.1080/23328940.2019.1653736] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Tokyo 2020 will likely be the most heat stressful Olympics to date, so preparation to mitigate the effects of humid heat will be essential for performance in several of the 33 sports. One key consideration is heat acclimation (HA); the repeated exposure to heat to elicit physiological and psychophysical adaptations that improve tolerance and exercise performance in the heat. Heat can be imposed in various ways, including exercise in the heat, hot water immersion, or passive exposure to hot air (e.g., sauna). The physical requirements of each sport will determine the impact that the heat has on performance, and the adaptations required from HA to mitigate these effects. This review focuses on one key adaptation, plasma volume expansion (PVE), and how the mode of HA may affect the kinetics of adaptation. PVE constitutes a primary HA-mediated adaptation and contributes to functional adaptations (e.g., lower heart rate and increased heat loss capacity), which may be particularly important in athletes of "sub-elite" cardiorespiratory fitness (e.g., team sports), alongside athletes of prolonged endurance events. This review: i) highlights the ability of exercise in the heat, hot-water immersion, and passive hot air to expand PV, providing the first quantitative assessment of the efficacy of different heating modes; ii) discusses how this may apply to athletes at Tokyo 2020; and iii) provides recommendations regarding the protocol of HA and the prospect for achieving PVE (and the related outcomes).
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Affiliation(s)
- Lorenz S Kissling
- The School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Ashley P Akerman
- The School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand.,Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - James D Cotter
- The School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
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29
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Akerman AP, Thomas KN, van Rij AM, Body ED, Alfadhel M, Cotter JD. Heat therapy vs. supervised exercise therapy for peripheral arterial disease: a 12-wk randomized, controlled trial. Am J Physiol Heart Circ Physiol 2019; 316:H1495-H1506. [DOI: 10.1152/ajpheart.00151.2019] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Peripheral arterial disease (PAD) is characterized by lower limb atherosclerosis impairing blood supply and causing walking-induced leg pain or claudication. Adherence to traditional exercise training programs is poor due to these symptoms despite exercise being a mainstay of conservative treatment. Heat therapy improves many cardiovascular health outcomes, so this study tested if this was a viable alternative cardiovascular therapy for PAD patients. Volunteers with PAD were randomized to 12 wk of heat ( n = 11; mean age 76 ± 8 yr, BMI 28.7 ± 3.5 kg/m2, 4 females) or exercise ( n = 11; 74 ± 10 yr, 28.5 ± 6.8 kg/m2, 3 females). Heat involved spa bathing at ∼39°C, 3–5 days/wk for ≤30 min, followed by ≤30 min of callisthenics. Exercise involved ≤90 min of supervised walking and gym-based exercise, 1–2 days/wk. Following the interventions, total walking distance during a 6-min walk test increased (from ∼350 m) by 41 m (95% CI: [13, 69], P = 0.006) regardless of group, and pain-free walking distance increased (from ∼170 m) by 43 m ([22, 63], P < 0.001). Systolic blood pressure was reduced more following heat (−7 mmHg, [−4, −10], P < 0.001) than following exercise (−3 mmHg, [0, −6], P = 0.078), and diastolic and mean arterial pressure decreased by 4 mmHg in both groups ( P = 0.002). There were no significant changes in blood volume, ankle-brachial index, or measures of vascular health. There were no differences in the improvement in functional or blood pressure outcomes between heat and exercise in individuals with PAD. NEW & NOTEWORTHY Heat therapy via hot-water immersion and supervised exercise both improved walking distance and resting blood pressure in peripheral arterial disease (PAD) patients over 12 wk. Adherence to heat therapy was excellent, and the heat intervention was well tolerated. The results of the current study indicate that heat therapy can improve functional ability and has potential as an effective cardiovascular conditioning tool for individuals with PAD. Listen to this article's corresponding podcast at https://ajpheart.podbean.com/e/heat-therapy-vs-exercise-in-peripheral-arterial-disease/ .
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Affiliation(s)
- Ashley P. Akerman
- School of Physical Education, Sport, and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Kate N. Thomas
- Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - Andre M. van Rij
- Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - E. Dianne Body
- Physiotherapy Department, Dunedin Public Hospital, Dunedin, New Zealand
| | - Mesfer Alfadhel
- Cardiology Department, Dunedin Public Hospital, Dunedin, New Zealand
| | - James D. Cotter
- School of Physical Education, Sport, and Exercise Sciences, University of Otago, Dunedin, New Zealand
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Guiney H, Lucas SJE, Cotter JD, Machado L. Investigating links between habitual physical activity, cerebrovascular function, and cognitive control in healthy older adults. Neuropsychologia 2019; 125:62-69. [PMID: 30682349 DOI: 10.1016/j.neuropsychologia.2019.01.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 11/29/2018] [Accepted: 01/22/2019] [Indexed: 12/20/2022]
Abstract
A growing body of evidence indicates regular physical activity benefits older adults' cognitive functioning, particularly when a high level of cognitive control is required. Recent research has pointed to improved cerebrovascular function as one mechanism through which such benefits might arise. This study built on previous research by investigating in 51 healthy older adults aged 60-72 years relationships between habitual physical activity, cerebrovascular function (indicated by resting cerebral blood flow velocity in the middle cerebral artery [n = 42], and its responsiveness to hypercapnia [n = 26] and hypocapnia [n = 25]), and cognitive control (inhibition and switching). Linear regression analyses showed moderate positive associations between physical activity and inhibitory control, but not cerebrovascular function. There were also no significant relationships between the cerebrovascular measures and cognitive control. These results indicate that regular engagement in physical activity is associated with superior inhibitory control in older adulthood, but cerebrovascular function was not found to explain those relationships. Taken together, the current findings reinforce reports of positive links between habitual physical activity and cognition in healthy older adults, but also signal that interrelationships with cerebrovascular function may be more complex than currently indicated by the literature, necessitating further research to elucidate the role cerebrovascular function might play in accounting for physical activity-cognition links in healthy older adults.
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Affiliation(s)
- Hayley Guiney
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand; Brain Research New Zealand, Auckland, New Zealand.
| | - Samuel J E Lucas
- Department of Physiology, University of Otago, Dunedin, New Zealand; School of Sport, Exercise, and Rehabilitation Sciences and Centre for Human Brain Health, University of Birmingham, Birmingham, England
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Liana Machado
- Department of Psychology and Brain Health Research Centre, University of Otago, Dunedin, New Zealand; Brain Research New Zealand, Auckland, New Zealand
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Lei TH, Cotter JD, Schlader ZJ, Stannard SR, Perry BG, Barnes MJ, Mündel T. On exercise thermoregulation in females: interaction of endogenous and exogenous ovarian hormones. J Physiol 2018; 597:71-88. [PMID: 30320879 DOI: 10.1113/jp276233] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 10/01/2018] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS One in two female athletes chronically take a combined, monophasic oral contraceptive pill (OCP). Previous thermoregulatory investigations proposed that an endogenous rhythm of the menstrual cycle still occurs with OCP usage. Forthcoming large international sporting events will expose female athletes to hot environments differing in their thermal profile, yet few data exist on how trained women will respond from both a thermoregulatory and performance stand-point. In the present study, we have demonstrated that a small endogenous rhythm of the menstrual cycle still affects Tcore and also that chronic OCP use attenuates the sweating response, whereas behavioural thermoregulation is maintained. Furthermore, humid heat affects both performance and thermoregulatory responses to a greater extent than OCP usage and the menstrual cycle does. ABSTRACT We studied thermoregulatory responses of ten well-trained ( V ̇ O 2 max , 57 ± 7 mL min-1 kg-1 ) women taking a combined, monophasic oral contraceptive pill (OCP) (≥12 months) during exercise in dry and humid heat, across their active OCP cycle. They completed four trials, each of resting and cycling at fixed intensities (125 and 150 W), aiming to assess autonomic regulation, and then a self-paced intensity (30-min work trial) to assess behavioural regulation. Trials were conducted in quasi-follicular (qF) and quasi-luteal (qL) phases in dry (DRY) and humid (HUM) heat matched for wet bulb globe temperature (WBGT) (27°C). During rest and exercise at 125 W, rectal temperature was 0.15°C higher in qL than qF (P = 0.05) independent of environment (P = 0.17). The onset threshold and thermosensitivity of local sweat rate and forearm blood flow relative to mean body temperature was unaffected by the OCP cycle (both P > 0.30). Exercise performance did not differ between quasi-phases (qF: 268 ± 31 kJ, qL: 263 ± 26 kJ, P = 0.31) but was 5 ± 7% higher during DRY than during HUM (273 ± 29 kJ, 258 ± 28 kJ; P = 0.03). Compared to matched eumenorrhoeic athletes, chronic OCP use impaired the sweating onset threshold and thermosensitivity (both P < 0.01). In well-trained, OCP-using women exercising in the heat: (i) a performance-thermoregulatory trade-off occurred that required behavioural adjustment; (ii) humidity impaired performance as a result of reduced evaporative power despite matched WBGT; and (iii) the sudomotor but not behavioural thermoregulatory responses were impaired compared to matched eumenorrhoeic athletes.
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Affiliation(s)
- Tze-Huan Lei
- School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Zachary J Schlader
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, USA
| | - Stephen R Stannard
- School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand
| | - Blake G Perry
- School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand
| | - Matthew J Barnes
- School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand
| | - Toby Mündel
- School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand
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Abstract
As major sporting events are often held in hot environments, increased interest in ways of optimally heat acclimating athletes to maximise performance has emerged. Heat acclimation involves repeated exercise sessions in hot conditions that induce physiological and thermoregulatory adaptations that attenuate heat-induced performance impairments. Current evidence-based guidelines for heat acclimation are clear, but the application of these recommendations is not always aligned with the time commitments and training priorities of elite athletes. Alternative forms of heat acclimation investigated include hot water immersion and sauna bathing, yet uncertainty remains around the efficacy of these methods for reducing heat-induced performance impairments, as well as how this form of heat stress may add to an athlete's overall training load. An understanding of how to optimally prescribe and periodise heat acclimation based on the performance determinants of a given event is limited, as is knowledge of how heat acclimation may affect the quality of concurrent training sessions. Finally, differences in individual athlete responses to heat acclimation need to be considered. This article addresses alternative methods of heat acclimation and heat exposure, explores gaps in literature around understanding the real world application of heat acclimation for athletes, and highlights specific athlete considerations for practitioners.
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Affiliation(s)
- Julia R Casadio
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.
- High Performance Sport New Zealand, PO Box 302 563, North Harbour, Auckland, 0751, New Zealand.
| | - Andrew E Kilding
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Paul B Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand
- High Performance Sport New Zealand, PO Box 302 563, North Harbour, Auckland, 0751, New Zealand
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Sixtus RP, Galland BC, Cotter JD. Foot cooling does not improve vigilance but may transiently reduce sleepiness. J Sleep Res 2018; 28:e12701. [PMID: 29749043 DOI: 10.1111/jsr.12701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 03/13/2018] [Accepted: 03/26/2018] [Indexed: 11/27/2022]
Abstract
Temperature of the skin (TSk ) and core (TC ) play key roles in sleep-wake regulation. The diurnal combination of low TSk and high TC facilitates alertness, whereas the transition to high TSk and low TC correlates with sleepiness. Sleepiness and deteriorating vigilance are induced with peripheral warming, whereas peripheral cooling appears to transiently improve vigilance in narcolepsy. This study aimed to test the hypothesis that foot cooling would maintain vigilance during extended wakefulness in healthy adults. Nine healthy young adult participants with habitually normal sleep completed three constant-routine trials in randomized crossover order. Trials began at 22:30 hours, and involved continuous mild foot cooling (30°C), moderate foot cooling (25°C) or no foot cooling, while undertaking six × 10-min Psychomotor Vigilance Tasks and seven × 7-min Karolinska Drowsiness Tasks, interspersed with questionnaires of sleepiness and thermal perceptions. Foot temperatures in control, mild and moderate cooling averaged 34.5 ± 0.5°C, 30.8 ± 0.2°C and 26.4 ± 0.1°C (all p < .01), while upper-limb temperatures remained stable (34-35°C) and TC declined (approximately -0.12°C per hr) regardless of trial (p = .84). Foot cooling did not improve vigilance (repeated-measures-ANOVA interaction for response speed: p = .45), but transiently reduced subjective sleepiness (-0.8 ± 0.8; p = .004). Participants felt cooler throughout cooling trials, but thermal comfort was unaffected (p = .43), as were almost all Karolinska Drowsiness Tasks' encephalographic parameters. In conclusion, mild or moderate cooling of the feet did not attenuate declines in vigilance or core temperature of healthy young adults during the period of normal sleep onset and early sleep, and any effect on sleepiness was small and transient.
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Affiliation(s)
- Ryan P Sixtus
- School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago, Dunedin, New Zealand
| | - Barbara C Galland
- Department of Women's and Children's Health, University of Otago, Dunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago, Dunedin, New Zealand
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Abstract
The application of molecular techniques to exercise biology has provided novel insight into the complexity and breadth of intracellular signaling networks involved in response to endurance-based exercise. Here we discuss several strategies that have high uptake by athletes and, on mechanistic grounds, have the potential to promote cellular adaptation to endurance training in skeletal muscle. Such approaches are based on the underlying premise that imposing a greater metabolic load and provoking extreme perturbations in cellular homeostasis will augment acute exercise responses that, when repeated over months and years, will amplify training adaptation.
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Affiliation(s)
- John A Hawley
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3000, Australia.
| | - Carsten Lundby
- Centre for Physical Activity Research, Copenhagen University Hospital, Copenhagen, Denmark
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Louise M Burke
- Exercise and Nutrition Research Program, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3000, Australia; Department of Sport Nutrition, Australian Institute of Sport, Belconnen, ACT, Australia
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Stadnyk AMJ, Rehrer NJ, Handcock PJ, Meredith-Jones KA, Cotter JD. No clear benefit of muscle heating on hypertrophy and strength with resistance training. Temperature (Austin) 2017; 5:175-183. [PMID: 30393753 DOI: 10.1080/23328940.2017.1391366] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 10/06/2017] [Accepted: 10/09/2017] [Indexed: 12/15/2022] Open
Abstract
Heat is a major stressor during exercise, though its value in driving adaptation is not well understood. Muscle heating can upregulate pathways facilitating protein synthesis and could thereby enhance effects of exercise training, however, few studies have investigated this possibility. We examined whether heating active muscle during resistance training differentially affected physical and functional adaptations. Within a randomised contralateral-limb control study, ten healthy, resistance-untrained individuals (21 ± 3 y; 5 female) completed 30 sessions of progressive resistance training (12 weeks), performing 4 × 8 unilateral knee extensions at 70% of 1RM. One randomly-allocated thigh was heated during, and for 20 min after, each session using an electric pad eliciting muscle temperatures of >38 °C (HOT); the contralateral limb remained unheated (CON). Training intensity was progressed using 4-weekly strength assessments. Quadricep lean mass (measured using DXA) increased by 15 ± 7% in HOT (p = 0.00) and 15 ± 6% in CON (p = 0.00); the difference being trivial (p = 0.94). Peak isokinetic torque at 90°.s-1 increased by 30 ± 25% (HOT; p = 0.00) and 34 ± 33% (CON; p = 0.01), with no difference (p = 0.84) between limbs. Rate of torque development increased ∼40%, with no difference between limbs (p = 0.73). The increase in 3-RM strength was also similar in HOT (75 ± 16%) and CON (71 ± 14%; p = 0.80 for difference). No differences in mass or strength changes were evident between sexes. In conclusion, supplemental heating of active muscle during and after each bout of resistance training showed no clear positive (or negative) effect on training-induced hypertrophy or function.
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Affiliation(s)
- Antony M J Stadnyk
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Nancy J Rehrer
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Phil J Handcock
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | | | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
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Lucas RAI, Wilson LC, Ainslie PN, Fan JL, Thomas KN, Cotter JD. Independent and interactive effects of incremental heat strain, orthostatic stress, and mild hypohydration on cerebral perfusion. Am J Physiol Regul Integr Comp Physiol 2017; 314:R415-R426. [PMID: 29212807 DOI: 10.1152/ajpregu.00109.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to identify the dose-dependent effects of heat strain and orthostasis [via lower body negative pressure (LBNP)], with and without mild hypohydration, on systemic function and cerebral perfusion. Eleven men (means ± SD: 27 ± 7 y; body mass 77 ± 6 kg), resting supine in a water-perfused suit, underwent progressive passive heating [0.5°C increments in core temperature (Tc; esophageal to +2.0°C)] while euhydrated (EUH) or hypohydrated (HYPO; 1.5-2% body mass deficit). At each thermal state, mean cerebral artery blood velocity (MCAvmean; transcranial Doppler), partial pressure of end-tidal carbon dioxide ([Formula: see text]), heart rate (HR) and mean arterial blood pressure (MAP; photoplethysmography) were measured continuously during LBNP (0, -15, -30, and -45 mmHg). Four subjects became intolerant before +2.0°C Tc, unrelated to hydration status. Without LBNP, decreases in [Formula: see text] accounted fully for reductions in MCAvmean across all Tc. With LBNP at heat tolerance (+1.5 or +2.0°C), [Formula: see text] accounted for 69 ± 25% of the change in MCAvmean. The HYPO condition did not affect MCAvmean or any cardiovascular variables during combined LBNP and passive heat stress (all P > 0.13). These findings indicate that hypocapnia accounted fully for the reduction in MCAvmean when passively heat stressed in the absence of LBNP and for two- thirds of the reduction when at heat tolerance combined with LBNP. Furthermore, when elevations in Tc are matched, mild hypohydration does not influence cerebrovascular or cardiovascular responses to LBNP, even when stressed by a combination of hyperthermia and LBNP.
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Affiliation(s)
- R A I Lucas
- Department of Physiology, University of Otago , Dunedin , New Zealand.,School of Physical Education, Sport and Exercise Sciences, University of Otago , Dunedin , New Zealand.,School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham , Birmingham , United Kingdom
| | - L C Wilson
- Department of Physiology, University of Otago , Dunedin , New Zealand.,School of Physical Education, Sport and Exercise Sciences, University of Otago , Dunedin , New Zealand.,Department of Medicine, University of Otago , Dunedin , New Zealand
| | - P N Ainslie
- Department of Physiology, University of Otago , Dunedin , New Zealand.,Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan , Kelowna , Canada
| | - J L Fan
- Department of Physiology, University of Otago , Dunedin , New Zealand.,Institute of Sports Science, Faculty of Biology and Medicine, University of Lausanne , Lausanne , Switzerland.,Lemanic Neuroscience Doctoral School, University of Lausanne , Lausanne , Switzerland
| | - K N Thomas
- Department of Physiology, University of Otago , Dunedin , New Zealand.,School of Physical Education, Sport and Exercise Sciences, University of Otago , Dunedin , New Zealand.,Department of Surgical Sciences, Dunedin School of Medicine, University of Otago . New Zealand
| | - J D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago , Dunedin , New Zealand
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Hoffman MD, Cotter JD, Goulet ÉD, Laursen PB. REBUTTAL from "Yes". Wilderness Environ Med 2017; 27:198-200. [PMID: 27291701 DOI: 10.1016/j.wem.2016.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 04/10/2016] [Accepted: 04/11/2016] [Indexed: 12/30/2022]
Affiliation(s)
- Martin D Hoffman
- Department of Physical Medicine & Rehabilitation, Department of Veterans Affairs, Northern California Health Care System, and University of California Davis Medical Center, Sacramento, CA.
| | - James D Cotter
- Exercise and Environmental Physiology, School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago, Dunedin, New Zealand(Dr Cotter)?>
| | - Éric D Goulet
- Research Centre on Aging, Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC, Quebec, Canada
| | - Paul B Laursen
- High Performance Sport New Zealand, and Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Aukland, Auckland, New Zealand
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Akerman AP, Lucas SJE, Katare R, Cotter JD. Heat and Dehydration Additively Enhance Cardiovascular Outcomes following Orthostatically-Stressful Calisthenics Exercise. Front Physiol 2017; 8:756. [PMID: 29062280 PMCID: PMC5640974 DOI: 10.3389/fphys.2017.00756] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 09/19/2017] [Indexed: 02/04/2023] Open
Abstract
Exercise and exogenous heat each stimulate multiple adaptations, but their roles are not well delineated, and that of the related stressor, dehydration, is largely unknown. While severe and prolonged hypohydration potentially “silences” the long-term heat acclimated phenotype, mild and transient dehydration may enhance cardiovascular and fluid-regulatory adaptations. We tested the hypothesis that exogenous heat stress and dehydration additively potentiate acute (24 h) cardiovascular and hematological outcomes following exercise. In a randomized crossover study, 10 physically-active volunteers (mean ± SD: 173 ± 11 cm; 72.1 ± 11.5 kg; 24 ± 3 year; 6 females) completed three trials of 90-min orthostatically-stressful calisthenics, in: (i) temperate conditions (22°C, 50% rh, no airflow; CON); (ii) heat (40°C, 60% rh) whilst euhydrated (HEAT), and (iii) heat with dehydration (no fluid ~16 h before and during exercise; HEAT+DEHY). Using linear mixed effects model analyses, core temperature (TCORE) rose 0.7°C more in HEAT than CON (95% CL: [0.5, 0.9]; p < 0.001), and another 0.4°C in HEAT+DEHY ([0.2, 0.5]; p < 0.001, vs. HEAT). Skin temperature also rose 1.2°C more in HEAT than CON ([0.6, 1.8]; p < 0.001), and similarly to HEAT+DEHY (p = 0.922 vs. HEAT). Peak heart rate was 40 b·min−1 higher in HEAT than in CON ([28, 51]; p < 0.001), and another 15 b·min−1 higher in HEAT+DEHY ([3, 27]; p = 0.011, vs. HEAT). Mean arterial pressure at 24-h recovery was not consistently below baseline after CON or HEAT (p ≥ 0.452), but was reduced 4 ± 1 mm Hg after HEAT+DEHY ([0, 8]; p = 0.020 vs. baseline). Plasma volume at 24 h after exercise increased in all trials; the 7% increase in HEAT was not reliably more than in CON (5%; p = 0.335), but was an additional 4% larger after HEAT+DEHY ([1, 8]; p = 0.005 vs. HEAT). Pooled-trial correlational analysis showed the rise in TCORE predicted the hypotension (r = −0.4) and plasma volume expansion (r = 0.6) at 24 h, with more hypotension reflecting more plasma expansion (r = −0.5). In conclusion, transient dehydration with heat potentiates short-term (24-h) hematological (hypervolemic) and cardiovascular (hypotensive) outcomes following calisthenics.
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Affiliation(s)
- Ashley P Akerman
- School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago, Dunedin, New Zealand.,Department of Physiology, Division of Health Sciences, University of Otago, Dunedin, New Zealand
| | - Samuel J E Lucas
- Department of Physiology, Division of Health Sciences, University of Otago, Dunedin, New Zealand.,School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Rajesh Katare
- Department of Physiology, Division of Health Sciences, University of Otago, Dunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago, Dunedin, New Zealand
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Casadio JR, Storey AG, Merien F, Kilding AE, Cotter JD, Laursen PB. Acute effects of heated resistance exercise in female and male power athletes. Eur J Appl Physiol 2017; 117:1965-1976. [PMID: 28748371 DOI: 10.1007/s00421-017-3671-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 06/22/2017] [Indexed: 11/28/2022]
Abstract
PURPOSE To determine the effects of heated resistance exercise on thermal strain, neuromuscular function and hormonal responses in power athletes. METHODS Sixteen (n = 8 female; 8 male) highly trained power athletes completed a combined strength and power resistance exercise session in hot (HOT ~30 °C) and temperate (CON ~20 °C) conditions. Human growth hormone (hGH), cortisol and testosterone concentrations in plasma, peak power (counter-movement jump, CMJ) and peak force (isometric mid-thigh pull) were measured before and after each training session; thermoregulatory responses were monitored during training. RESULTS Skin temperature, thermal sensation and thermal discomfort were higher in HOT compared with CON. Sweat rate was higher in HOT for males only. Compared with CON, HOT had trivial effects on core temperature and heart rate. During HOT, there was a possible increase in upper-body power (medicine ball throw) in females [3.4% (90% CL -1.5, 8.6)] and males [(3.3% (-0.1, 6.9)], while lower-body power (vertical jump) was enhanced in males only [3.2% (-0.4, 6.9)]. Following HOT, CMJ peak power [4.4% (2.5; 6.3)] and strength [8.2% (3.1, 13.6)] were enhanced in female athletes, compared with CON, while effects in males were unclear. Plasma hGH concentration increased in females [83% (18; 183)] and males [107% (-21; 444)] in HOT compared with CON, whereas differential changes occurred for cortisol and testosterone. CONCLUSION Heated resistance exercise enhanced power and increased plasma hGH concentration in female and males power athletes. Further research is required to assess the ergogenic potential of resistance exercise in the heat.
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Affiliation(s)
- Julia R Casadio
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand. .,High Performance Sport New Zealand, Auckland, New Zealand.
| | - Adam G Storey
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.,High Performance Sport New Zealand, Auckland, New Zealand
| | - Fabrice Merien
- AUT-Roche Diagnostics Laboratory, School of Science, Auckland University of Technology, Auckland, New Zealand
| | - Andrew E Kilding
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Paul B Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.,High Performance Sport New Zealand, Auckland, New Zealand
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Hoffman MD, Cotter JD, Goulet ÉD, Laursen PB. VIEW: Is Drinking to Thirst Adequate to Appropriately Maintain Hydration Status During Prolonged Endurance Exercise? Yes. Wilderness Environ Med 2017; 27:192-5. [PMID: 27291699 DOI: 10.1016/j.wem.2016.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/03/2016] [Accepted: 03/09/2016] [Indexed: 10/21/2022]
Affiliation(s)
- Martin D Hoffman
- Department of Physical Medicine & Rehabilitation Department of Veterans Affairs, Northern California Health Care System, and University of California Davis Medical Center, Sacramento, CA, USA (Dr Hoffman)
| | - James D Cotter
- Exercise and Environmental Physiology, School of Physical Education, Sport and Exercise Sciences Division of Sciences, University of Otago, Dunedin New Zealand (Dr Cotter)
| | - Éric D Goulet
- Research Centre on Aging, Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC Canada (Dr Goulet)
| | - Paul B Laursen
- High Performance Sport New Zealand, and Sports Performance Research Institute New Zealand (SPRINZ) Auckland University of Technology, Auckland New Zealand (Dr Laursen)
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Lei T, Stannard SR, Perry BG, Schlader ZJ, Cotter JD, Mündel T. Influence of menstrual phase and arid vs. humid heat stress on autonomic and behavioural thermoregulation during exercise in trained but unacclimated women. J Physiol 2017; 595:2823-2837. [PMID: 27900769 PMCID: PMC5407968 DOI: 10.1113/jp273176] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 11/10/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Despite an attenuated fluctuation in ovarian hormone concentrations in well-trained women, one in two of such women believe their menstrual cycle negatively impacts training and performance. Forthcoming large international events will expose female athletes to hot environments, and studies evaluating aerobic exercise performance in such environments across the menstrual cycle are sparse, with mixed findings. We have identified that autonomic heat loss responses at rest and during fixed-intensity exercise in well-trained women are not affected by menstrual cycle phase, but differ between dry and humid heat. Furthermore, exercise performance is not different across the menstrual cycle, yet is lower in humid heat, in conjunction with reduced evaporative cooling. Menstrual cycle phase does not appear to affect exercise performance in the heat in well-trained women, but humidity impairs performance, probably due to reduced evaporative power. ABSTRACT We studied thermoregulatory responses of ten well-trained [V̇O2 max , 57 (7) ml min-1 kg-1 ] eumenorrheic women exercising in dry and humid heat, across their menstrual cycle. They completed four trials, each of resting and cycling at fixed intensities (125 and 150 W), to assess autonomic regulation, then self-paced intensity (30 min work trial), to assess behavioural regulation. Trials were in early-follicular (EF) and mid-luteal (ML) phases in dry (DRY) and humid (HUM) heat matched for wet bulb globe temperature (WBGT, 27°C). During rest and fixed-intensity exercise, rectal temperature was ∼0.2°C higher in ML than EF (P < 0.01) independent of environment (P = 0.66). Mean skin temperature did not differ between menstrual phases (P ≥ 0.13) but was higher in DRY than HUM (P < 0.01). Local sweat rate and/or forearm blood flow differed as a function of menstrual phase and environment (interaction: P ≤ 0.01). Exercise performance did not differ between phases [EF: 257 (37), ML: 255 (43) kJ, P = 0.62], but was 7 (9)% higher in DRY than HUM [263 (39), 248 (40) kJ; P < 0.01] in conjunction with equivalent autonomic regulation and thermal strain but higher evaporative cooling [16 (6) W m2 ; P < 0.01]. In well-trained women exercising in the heat: (1) menstrual phase did not affect performance, (2) humidity impaired performance due to reduced evaporative cooling despite matched WBGT and (3) behavioural responses nullified thermodynamic and autonomic differences associated with menstrual phase and dry vs. humid heat.
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Affiliation(s)
- Tze‐Huan Lei
- School of Sport and ExerciseMassey UniversityPalmerston NorthNew Zealand
| | | | - Blake G. Perry
- School of Sport and ExerciseMassey UniversityPalmerston NorthNew Zealand
| | - Zachary J. Schlader
- Department of Exercise and Nutrition SciencesUniversity at BuffaloBuffaloNYUSA
| | - James D. Cotter
- School of Physical EducationSport and Exercise SciencesUniversity of OtagoDunedinNew Zealand
| | - Toby Mündel
- School of Sport and ExerciseMassey UniversityPalmerston NorthNew Zealand
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Rehrer NJ, Wijering L, Cotter JD. Can Increased Sodium Intake Reduce Exercise-associated Hyponatremia? Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000517746.81340.0d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Francois ME, Graham MJ, Parr EB, Rehrer NJ, Lucas SJE, Stavrianeas S, Cotter JD. Similar metabolic response to lower- versus upper-body interval exercise or endurance exercise. Metabolism 2017; 68:1-10. [PMID: 28183441 DOI: 10.1016/j.metabol.2016.11.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 10/25/2016] [Accepted: 11/22/2016] [Indexed: 01/04/2023]
Abstract
PURPOSE To compare energy use and substrate partitioning arising from repeated lower- versus upper-body sprints, or endurance exercise, across a 24-h period. METHODS Twelve untrained males (24±4 y) completed three trials in randomized order: (1) repeated sprints (five 30-s Wingate, 4.5-min recovery) on a cycle ergometer (SITLegs); (2) 50-min continuous cycling at 65% V̇O2max (END); (3) repeated sprints on an arm-crank ergometer (SITArms). Respiratory gas exchange was assessed before and during exercise, and at eight points across 22h of recovery. RESULTS Metabolic rate was elevated to greater extent in the first 8h after SITLegs than SITArms (by 0.8±1.1kJ/min, p=0.03), and tended to be greater than END (by 0.7±1.3kJ/min, p=0.08). Total 24-h energy use (exercise+recovery) was equivalent between SITLegs and END (p = 0.55), and SITLegs and SITArms (p=0.13), but 24-h fat use was higher with SITLegs than END (by 26±38g, p=0.04) and SITArms (by 27±43g, p=0.05), whereas carbohydrate use was higher with SITArms than SITLegs (by 32±51g, p=0.05). Plasma volume-corrected post-exercise and fasting glucose and lipid concentrations were unchanged. CONCLUSION Despite much lower energy use during five sprints than 50-min continuous exercise, 24-h energy use was not reliably different. However, (i) fat metabolism was greater after sprints, and (ii) carbohydrate metabolism was greater in the hours after sprints with arms than legs, while 24-h energy usage was comparable. Thus, sprints using arms or legs may be an important adjunct exercise mode for metabolic health.
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Affiliation(s)
- Monique E Francois
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Matthew J Graham
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Evelyn B Parr
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Nancy J Rehrer
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Samuel J E Lucas
- Department of Physiology, University of Otago, Dunedin, New Zealand
| | | | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand.
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Thomas KN, van Rij AM, Lucas SJE, Cotter JD. Lower-limb hot-water immersion acutely induces beneficial hemodynamic and cardiovascular responses in peripheral arterial disease and healthy, elderly controls. Am J Physiol Regul Integr Comp Physiol 2016; 312:R281-R291. [PMID: 28003211 DOI: 10.1152/ajpregu.00404.2016] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/19/2016] [Accepted: 12/19/2016] [Indexed: 11/22/2022]
Abstract
Passive heat induces beneficial perfusion profiles, provides substantive cardiovascular strain, and reduces blood pressure, thereby holding potential for healthy and cardiovascular disease populations. The aim of this study was to assess acute responses to passive heat via lower-limb, hot-water immersion in patients with peripheral arterial disease (PAD) and healthy, elderly controls. Eleven patients with PAD (age 71 ± 6 yr, 7 male, 4 female) and 10 controls (age 72 ± 7 yr, 8 male, 2 female) underwent hot-water immersion (30-min waist-level immersion in 42.1 ± 0.6°C water). Before, during, and following immersion, brachial and popliteal artery diameter, blood flow, and shear stress were assessed using duplex ultrasound. Lower-limb perfusion was measured also using venous occlusion plethysmography and near-infrared spectroscopy. During immersion, shear rate increased (P < 0.0001) comparably between groups in the popliteal artery (controls: +183 ± 26%; PAD: +258 ± 54%) and brachial artery (controls: +117 ± 24%; PAD: +107 ± 32%). Lower-limb blood flow increased significantly in both groups, as measured from duplex ultrasound (>200%), plethysmography (>100%), and spectroscopy, while central and peripheral pulse-wave velocity decreased in both groups. Mean arterial blood pressure was reduced by 22 ± 9 mmHg (main effect P < 0.0001, interaction P = 0.60) during immersion, and remained 7 ± 7 mmHg lower 3 h afterward. In PAD, popliteal shear profiles and claudication both compared favorably with those measured immediately following symptom-limited walking. A 30-min hot-water immersion is a practical means of delivering heat therapy to PAD patients and healthy, elderly individuals to induce appreciable systemic (chronotropic and blood pressure lowering) and hemodynamic (upper and lower-limb perfusion and shear rate increases) responses.
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Affiliation(s)
- Kate N Thomas
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand; .,School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - André M van Rij
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Samuel J E Lucas
- Department of Physiology, University of Otago, Dunedin, New Zealand; and.,School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
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Graham MJ, Lucas SJE, Francois ME, Stavrianeas S, Parr EB, Thomas KN, Cotter JD. Low-Volume Intense Exercise Elicits Post-exercise Hypotension and Subsequent Hypervolemia, Irrespective of Which Limbs Are Exercised. Front Physiol 2016; 7:199. [PMID: 27303310 PMCID: PMC4885852 DOI: 10.3389/fphys.2016.00199] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/17/2016] [Indexed: 11/18/2022] Open
Abstract
Introduction: Exercise reduces arterial and central venous blood pressures during recovery, which contributes to its valuable anti-hypertensive effects and to facilitating hypervolemia. Repeated sprint exercise potently improves metabolic function, but its cardiovascular effects (esp. hematological) are less well-characterized, as are effects of exercising upper versus lower limbs. The purposes of this study were to identify the acute (<24 h) profiles of arterial blood pressure and blood volume for (i) sprint intervals versus endurance exercise, and (ii) sprint intervals using arms versus legs. Methods: Twelve untrained males completed three cycling exercise trials; 50-min endurance (legs), and 5*30-s intervals using legs or arms, in randomized and counterbalanced sequence, at a standardized time of day with at least 8 days between trials. Arterial pressure, hemoglobin concentration and hematocrit were measured before, during and across 22 h after exercise, the first 3 h of which were seated rest. Results: The post-exercise hypotensive response was larger after leg intervals than endurance (AUC: 7540 ± 3853 vs. 3897 ± 2757 mm Hg·min, p = 0.049, 95% CI: 20 to 6764), whereas exercising different limbs elicited similar hypotension (arms: 6420 ± 3947 mm Hg·min, p = 0.48, CI: −1261 to 3896). In contrast, arterial pressure at 22 h was reduced after endurance but not after leg intervals (−8 ± 8 vs. 0 ± 7 mm Hg, p = 0.04, CI: 7 ± 7) or reliably after arm intervals (−4 ± 8 mm Hg, p = 0.18 vs. leg intervals). Regardless, plasma volume expansion at 22 h was similar between leg intervals and endurance (both +5 ± 5%; CI: −5 to 5%) and between leg and arm intervals (arms: +5 ± 7%, CI: −8 to 5%). Conclusions: These results emphasize the relative importance of central and/or systemic factors in post-exercise hypotension, and indicate that markedly diverse exercise profiles can induce substantive hypotension and subsequent hypervolemia. At least for endurance exercise, this hypervolemia may not depend on the volume of post-exercise hypotension. Finally, endurance exercise led to reduced blood pressure the following day, but sprint interval exercise did not.
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Affiliation(s)
- Matthew J Graham
- School of Physical Education, Sport and Exercise Sciences, University of Otago Dunedin, New Zealand
| | - Samuel J E Lucas
- Department of Physiology, University of OtagoDunedin, New Zealand; School of Sport, Exercise and Rehabilitation Sciences, University of BirminghamBirmingham, UK
| | - Monique E Francois
- School of Physical Education, Sport and Exercise Sciences, University of Otago Dunedin, New Zealand
| | | | - Evelyn B Parr
- School of Physical Education, Sport and Exercise Sciences, University of Otago Dunedin, New Zealand
| | - Kate N Thomas
- School of Physical Education, Sport and Exercise Sciences, University of OtagoDunedin, New Zealand; Department of Surgical Sciences, Dunedin School of Medicine, University of OtagoDunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago Dunedin, New Zealand
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Casadio JR, Kilding AE, Siegel R, Cotter JD, Laursen PB. Periodizing heat acclimation in elite Laser sailors preparing for a world championship event in hot conditions. Temperature (Austin) 2016; 3:437-443. [PMID: 28349083 PMCID: PMC5079264 DOI: 10.1080/23328940.2016.1184367] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 04/21/2016] [Accepted: 04/23/2016] [Indexed: 11/09/2022] Open
Abstract
Purpose: To examine the retention and re-acclimation responses during a periodized heat acclimation (HA) protocol in elite sailors preparing for the 2013 World Championships in Muscat, Oman (∼27–30°C, 40–60% RH). Methods: Two elite male Laser class sailors completed 5 consecutive days of HA (60 min per day in 35°C, 60% RH). Heat response tests (HRT) were performed on day 1 and 5 of HA, then 1 (decay 1, D1) and 2 (D2) weeks following HA. Participants were then re-acclimated (RA) for 2 days, within the next week, before a final HRT ∼72 h post-RA. Rectal temperature, plasma volume, heart rate, sweat rate, as well as thermal discomfort and rating of perceived exertion were measured during each HRT. Results: Rectal temperature decreased with HA (0.46 ± 0.05°C), while individual responses following D1, D2 and RA varied. Heart rate (14 ± 7 bpm), thermal discomfort (0.6 ± 0.1 AU) and rating of perceived exertion (1.8 ± 0.6 AU) decreased across HA, and adaptations were retained by D2. Plasma volume steadily increased over the decay period (D2 = 8.0 ± 1.3%) and after RA (15.5 ± 1.1%) compared with baseline. RA resulted in further thermoregulatory improvements in each Athlete, although individual adjustments varied. Conclusion: Heat strain was reduced in elite Laser sailors following HA and most thermoregulatory adaptations were retained for 2 weeks afterwards. RA may ‘top up’ adaptations after 2 weeks of HA decay.
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Affiliation(s)
- Julia R Casadio
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand; High Performance Sport New Zealand, Auckland, New Zealand
| | | | | | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago , Dunedin, New Zealand
| | - Paul B Laursen
- Sports Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand; High Performance Sport New Zealand, Auckland, New Zealand
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Lucas SJE, Helge JW, Schütz UHW, Goldman RF, Cotter JD. Moving in extreme environments: extreme loading; carriage versus distance. Extrem Physiol Med 2016; 5:6. [PMID: 27110357 PMCID: PMC4840901 DOI: 10.1186/s13728-016-0047-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 04/01/2016] [Indexed: 12/17/2022]
Abstract
This review addresses human capacity for movement in the context of extreme loading and with it the combined effects of metabolic, biomechanical and gravitational stress on the human body. This topic encompasses extreme duration, as occurs in ultra-endurance competitions (e.g. adventure racing and transcontinental races) and expeditions (e.g. polar crossings), to the more gravitationally limited load carriage (e.g. in the military context). Juxtaposed to these circumstances is the extreme metabolic and mechanical unloading associated with space travel, prolonged bedrest and sedentary lifestyle, which may be at least as problematic, and are therefore included as a reference, e.g. when considering exposure, dangers and (mal)adaptations. As per the other reviews in this series, we describe the nature of the stress and the associated consequences; illustrate relevant regulations, including why and how they are set; present the pros and cons for self versus prescribed acute and chronic exposure; describe humans’ (mal)adaptations; and finally suggest future directions for practice and research. In summary, we describe adaptation patterns that are often U or J shaped and that over time minimal or no load carriage decreases the global load carrying capacity and eventually leads to severe adverse effects and manifest disease under minimal absolute but high relative loads. We advocate that further understanding of load carrying capacity and the inherent mechanisms leading to adverse effects may advantageously be studied in this perspective. With improved access to insightful and portable technologies, there are some exciting possibilities to explore these questions in this context.
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Affiliation(s)
- Samuel J E Lucas
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT UK ; Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Jørn W Helge
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Uwe H W Schütz
- Department of Diagnostic and Interventional Radiology, University Hospital of Ulm, Ulm, Germany ; Orthopaedic Consulting Office at the Green Tower and Medical Pain Centre Lake Constance-Upper Swabia, Ravensburg, Germany
| | | | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
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Thomas KN, Cotter JD, Williams MJA, van Rij AM. Diagnosis, Incidence, and Clinical Implications of Perioperative Myocardial Injury in Vascular Surgery. Vasc Endovascular Surg 2016; 50:247-55. [DOI: 10.1177/1538574416637441] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Introduction: Routine measurement of cardiac biomarkers such as troponin T (TnT) is recommended perioperatively, especially in high-risk vascular surgery. Long-term prognosis is worse even in those with nonspecific perioperative myocardial injury. However, a clear understanding of these biomarker profiles and how they should affect patient management is lacking. Methods: We examined the perioperative profile of high-sensitivity TnT (hsTnT) release in 85 patients undergoing elective major vascular surgery. Plasma hsTnT was measured preoperatively, at 6, 12, and 24 hours postoperatively, and then every 24 hours for a maximum of 5 days. Significant elevations in hsTnT with/without clinical indicators of ischemia were used to diagnose myocardial infarction or injury. Results: A high incidence of myocardial injury was evident (46% had elevated hsTnT); only 5% were associated with myocardial infarction, and 41% were due to myocardial injury. Conclusions: This study emphasizes the high incidence of perioperative myocardial injury and stress in vascular surgery as revealed by the use of the robust and very sensitive biomarker of myocardial damage, hsTnT. The high availability and swift development of increasingly sensitive assays allow detection of abnormal elevated hsTnT levels in a higher proportion of the population. Consequent challenges are the reduced specificity to separate acute events as well as to deduce the prognostic value of elevations due to confusing criteria; this is especially the case in a patient group with multiple comorbidities that affect hsTnT levels chronically.
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Affiliation(s)
- Kate N. Thomas
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - James D. Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Michael J. A. Williams
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - André M. van Rij
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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50
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Thomas KN, Cotter JD, Williams MJA, van Rij AM. Repeated Episodes of Remote Ischemic Preconditioning for the Prevention of Myocardial Injury in Vascular Surgery. Vasc Endovascular Surg 2016; 50:140-6. [PMID: 27075990 DOI: 10.1177/1538574416639150] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Remote ischemic preconditioning (RIPC) involves the phenomenon whereby transient episodes of limb ischemia induced by cuff inflation provide cardioprotection. The effectiveness of RIPC in vascular surgery is uncertain. This randomized, controlled trial was designed to investigate the potential of two episodes of RIPC to provide myocardial protection in patients undergoing vascular surgery. DESIGN AND METHODS Patients undergoing an elective major vascular procedure (open abdominal aortic aneurysm (AAA) repair, endovascular aneurysm repair, and lower-limb bypass grafting) were randomized into RIPC group (n = 42) or control group (n = 43). Remote ischemic preconditioning consisted of three 5-minute cycles of upper limb cuff occlusion with 5-minutes of reperfusion between cycles, both 24 hours and immediately before surgery. Control patients received a similarly timed sham treatment. Cardiac high-sensitivity troponin T (hsTnT) concentration was measured in plasma at 6, 12, 24, and 48 hours post-surgery, and at 72, 96, and 120 hours in patients still in hospital. Perioperative clinical adverse events and readmissions within ∼12 months were recorded. RESULTS Myocardial injury was demonstrated perioperatively in 43% of RIPC patients and 49% of controls, as defined by a significant hsTnT elevation. These incidences were statistically equivalent (odds ratio 0.79, 95% confidence interval 0.33-1.85, P = .58). The 48-hour area under the curve for hsTnT change from baseline also revealed no difference (RIPC vs control median: 5.3 vs 7.5 ng/L.h, P = .22). Each group had one type I and one type II myocardial infarction and no difference in complications or readmissions. CONCLUSIONS This trial could not confirm that two episodes of RIPC reduce myocardial injury following vascular surgery. Along with other equivocal studies, it appears that RIPC does not induce a clear benefit in vascular surgery.
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Affiliation(s)
- Kate N Thomas
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Michael J A Williams
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - André M van Rij
- Department of Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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