1
|
Daanen HAM, Dijkstra I, Abbink E, de Jong IJ, Wolf ST, Bongers CCWG, Hondema LS, Eijsvogels TMH, Kingma BRM. Sex differences in thermophysiological responses of elderly to low-intensity exercise during uncompensable heat strain. Eur J Appl Physiol 2024; 124:2451-2459. [PMID: 38551682 PMCID: PMC11322401 DOI: 10.1007/s00421-024-05457-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 02/27/2024] [Indexed: 08/16/2024]
Abstract
PURPOSE The rising frequency of extreme heat events poses an escalating threat of heat-related illnesses and fatalities, placing an additional strain on global healthcare systems. Whether the risk of heat-related issues is sex specific, particularly among the elderly, remains uncertain. METHODS 16 men and 15 women of similar age (69 ± 5 years) were exposed to an air temperature of 39.1 ± 0.3 °C and a relative humidity (RH) of 25.1 ± 1.9%, during 20 min of seated rest and at least 40 min of low-intensity (10 W) cycling exercise. RH was gradually increased by 2% every 5 min starting at minute 30. We measured sweat rate, heart rate, thermal sensation, and the rise in gastrointestinal temperature (Tgi) and skin temperature (Tsk). RESULTS Tgi consistently increased from minute 30 to 60, with no significant difference between females and males (0.012 ± 0.004 °C/min vs. 0.011 ± 0.005 °C/min; p = 0.64). Similarly, Tsk increase did not differ between females and males (0.044 ± 0.007 °C/min vs. 0.038 ± 0.011 °C/min; p = 0.07). Females exhibited lower sweat rates than males (0.29 ± 0.06 vs. 0.45 ± 0.14 mg/m2/min; p < 0.001) in particular at relative humidities exceeding 30%. No sex differences in heart rate and thermal sensation were observed. CONCLUSION Elderly females exhibit significantly lower sweat rates than their male counterparts during low-intensity exercise at ambient temperatures of 39 °C when humidity exceeds 30%. However, both elderly males and females demonstrate a comparable rise in core temperature, skin temperature, and mean body temperature, indicating similar health-related risks associated with heat exposure.
Collapse
Affiliation(s)
- Hein A M Daanen
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 7, 1081BT, Amsterdam, The Netherlands.
| | - Iris Dijkstra
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 7, 1081BT, Amsterdam, The Netherlands
| | - Emma Abbink
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 7, 1081BT, Amsterdam, The Netherlands
| | - Iris J de Jong
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 7, 1081BT, Amsterdam, The Netherlands
| | - S Tony Wolf
- Department of Kinesiology, University of Georgia, Athens, GA, USA
| | - Coen C W G Bongers
- School of Sport and Exercise, HAN University of Applied Sciences, Nijmegen, The Netherlands
- Department of Medical Biosciences, Exercise Physiology Research Group, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Laurens S Hondema
- Public Health Service of Amsterdam (GGD), Amsterdam, The Netherlands
| | - Thijs M H Eijsvogels
- Department of Medical Biosciences, Exercise Physiology Research Group, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Boris R M Kingma
- Department Human Performance, Unit Defence, Safety and Security, TNO, Organization for Applied Sciences, Soesterberg, The Netherlands
| |
Collapse
|
2
|
Verney J, Lambert C, Isacco L, Beraud D, Boscaro A, Pereira B, Costes F, Rannou F, Julian V, Duclos M, Boirie Y, Thivel D, Bailly M. Similar maximal aerobic capacity but lower energy efficiency during low-to-moderate exercise in women with constitutional thinness: new results from the NUTRILEAN study. Eur J Appl Physiol 2024:10.1007/s00421-024-05540-0. [PMID: 38904774 DOI: 10.1007/s00421-024-05540-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Accepted: 06/06/2024] [Indexed: 06/22/2024]
Abstract
PURPOSE Individuals with constitutional thinness have been presented with a lower muscular energy metabolism at the cellular level but their effective aerobic capacities and exercise-related energy efficiency remains unexplored. The present study compares maximal and sub-maximal aerobic capacities between subjects with constitutional thinness and age-matched normal-weight ones. METHODS Anthropometric measures, body composition (Dual-X-ray absorptiometry), physical activity and sedentary time (GT3x actigraphs), and maximal aerobic capacities (cyclingV ˙ O 2peak test) were assessed in 18 constitutionally thin (CT-body mass index < 17.5 kg m-2) and 17 normal-weight (NW-body mass index between 20 and 25 kg m-2) women. Energy efficiency was assessed during a submaximal cycling test and a walking exercise. RESULTS CT had a lower body mass and body mass index compared to NW. Absolute peak oxygen uptake and maximal aerobic power were lower in CT subjects compared to NW (ES: - 1.63 [- 2.40; - 0.86] and - 1.32 [- 2.05; - 0.58], p < 0.001).V ˙ O 2peak related to body mass was not different between groups. Gross and net efficiency (ES: - 0.78 [- 1.48; - 0.06], p = 0.03 and ES: - 0.73 [- 1.43; - 0.01], p = 0.05) were lower in CT compared to NW during the submaximal cycling exercise. The gross energy cost of walking related to body mass was lower in subjects with CT (ES: - 1.80 [- 2.60; - 0.97, p = 0.05), with no difference for the net one. Perceived exertion was similar between groups in responses to both submaximal exercises. CONCLUSION Constitutionally thin women do not show impaired aerobic capacities at moderate to maximal intensities despite lower energy efficiency while cycling and walking at low-to-moderate intensities.
Collapse
Affiliation(s)
- Julien Verney
- Laboratory of the Metabolic Adaptations to Exercise Under Physiological and Pathological Conditions (AME2P), Clermont Auvergne University, CS 60026, 63178, Aubière Cedex, France.
| | - Céline Lambert
- Biostatistics Unit, DRCI, CHU Clermont-Ferrand, 63000, Clermont-Ferrand, France
| | - Laurie Isacco
- Laboratory of the Metabolic Adaptations to Exercise Under Physiological and Pathological Conditions (AME2P), Clermont Auvergne University, CS 60026, 63178, Aubière Cedex, France
| | - Duane Beraud
- Laboratory of the Metabolic Adaptations to Exercise Under Physiological and Pathological Conditions (AME2P), Clermont Auvergne University, CS 60026, 63178, Aubière Cedex, France
| | - Audrey Boscaro
- Laboratory of the Metabolic Adaptations to Exercise Under Physiological and Pathological Conditions (AME2P), Clermont Auvergne University, CS 60026, 63178, Aubière Cedex, France
| | - Bruno Pereira
- Biostatistics Unit, DRCI, CHU Clermont-Ferrand, 63000, Clermont-Ferrand, France
| | - Frédéric Costes
- Department of Sport Medicine and Functional Explorations, CHU Clermont-Ferrand, CRNH, INRA, University of Clermont Auvergne, 63000, Clermont-Ferrand, France
| | - Fabrice Rannou
- Department of Sport Medicine and Functional Explorations, CHU Clermont-Ferrand, CRNH, INRA, University of Clermont Auvergne, 63000, Clermont-Ferrand, France
| | - Valérie Julian
- Department of Sport Medicine and Functional Explorations, CHU Clermont-Ferrand, CRNH, INRA, University of Clermont Auvergne, 63000, Clermont-Ferrand, France
| | - Martine Duclos
- Department of Sport Medicine and Functional Explorations, CHU Clermont-Ferrand, CRNH, INRA, University of Clermont Auvergne, 63000, Clermont-Ferrand, France
| | - Yves Boirie
- Department of Clinical Nutrition, CHU Clermont-Ferrand, Diet and Musculoskeletal Health Team, CRNH, INRA, University of Clermont Auvergne, 63000, Clermont-Ferrand, France
| | - David Thivel
- Laboratory of the Metabolic Adaptations to Exercise Under Physiological and Pathological Conditions (AME2P), Clermont Auvergne University, CS 60026, 63178, Aubière Cedex, France
| | - Mélina Bailly
- Laboratory of the Metabolic Adaptations to Exercise Under Physiological and Pathological Conditions (AME2P), Clermont Auvergne University, CS 60026, 63178, Aubière Cedex, France
| |
Collapse
|
3
|
Sasajima S, Kubo K. Effect of Static Stretching on Tendon Hysteresis and Efficiency During Repetitive Jumping. J Strength Cond Res 2024; 38:1041-1047. [PMID: 38595295 DOI: 10.1519/jsc.0000000000004760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Indexed: 04/11/2024]
Abstract
ABSTRACT Sasajima, S and Kubo, K. Effect of static stretching on tendon hysteresis and efficiency during repetitive jumping. J Strength Cond Res 38(6): 1041-1047, 2024-To date, no studies have experimentally shown a relationship between tendon hysteresis and exercise efficiency. However, previous studies showed that tendon hysteresis decreased immediately after static stretching. The purposes of this study were to (a) investigate the change in tendon hysteresis during the recovery period after static stretching and (b) determine whether exercise efficiency is enhanced because of the decline of tendon hysteresis after static stretching. For stretching (1 minute × 4 sets) and control conditions, tendon hysteresis was measured during ramp (i.e., lower strain rate of tendon) and ballistic (i.e., higher strain rate of tendon) contractions before, immediately, 15, 30, 45, and 60 minutes after interventions. In addition, electromyograms of the plantar flexor muscles (medial gastrocnemius [MG], lateral gastrocnemius [LG], and soleus muscles [SOL]) and oxygen consumption (V̇O 2 ) were measured during 10 minutes of submaximal repetitive jumping after both interventions. Tendon hysteresis (during ramp and ballistic contractions) reduced by static stretching persisted for up to 60 minutes (effect of time p < 0.001). During repetitive jumping, no differences in electromyograms of the plantar flexor muscles (effect of condition p = 0.786 for MG, p = 0.124 for LG, p = 0.682 for SOL) or V̇O 2 (effect of condition p = 0.534) were found between stretching and control conditions. These results suggest that the reduction in tendon hysteresis because of static stretching continues until 60 minutes after the end of stretching, and static stretching does not change the efficiency (evaluated by electromyograms of the plantar flexor muscles and V̇O 2 ) during submaximal repetitive jumping.
Collapse
Affiliation(s)
- Shuhei Sasajima
- Department of Life Science, The University of Tokyo, Tokyo, Japan
| | | |
Collapse
|
4
|
Chang G, Moiteiro Manteigas H, Strutton PH, Mullington CJ. An evaluation of a healthy participant laboratory model of epidural hyperthermia: a physiological study. Int J Obstet Anesth 2024; 57:103961. [PMID: 38199895 DOI: 10.1016/j.ijoa.2023.103961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 11/01/2023] [Accepted: 11/27/2023] [Indexed: 01/12/2024]
Abstract
BACKGROUND Hyperthermia complicates 21% of cases of intrapartum epidural analgesia, but the mechanism is unclear. One hypothesis is that blockade of cholinergic sympathetic nerves prevents active vasodilation and sweating, thus limiting heat loss. Because labour increases heat production, this could create a situation in which heat production exceeds loss, causing body temperature to rise. This physiological study tested a novel laboratory model of epidural-related hyperthermia, using exercise to simulate the increased heat production of labour and surface insulation to simulate the effect of epidural analgesia. METHODS Twelve healthy non-pregnant participants (six female) cycled an ergometer for two hours at 20 Watts (W) on two occasions: once with surface insulation (intervention) and once without (control). Core temperature, skin temperature (eight sites), and heat loss (eight sites) were recorded. Mean body temperature and heat production were calculated. Values are mean (SD). RESULTS Exercise increased heat production on both visits (intervention 38 (18) W; control 37 (31) W; P = 0.94). Total heat loss was less on the intervention visit (intervention 115 (19) W; control 129 (23) W; P = 0.002). Core temperature increased on both visits (intervention 0.21 (0.37)°C; control 0.19 (0.27)°C; P < 0.001). The increase in mean body temperature was greater on the intervention visit (intervention 0.47 (0.41)°C; control 0.25 (0.19)°C; P = 0.007). CONCLUSIONS This laboratory model predicts that labour epidural analgesia limits heat loss by >14 W. Once the model is validated, it could be used to test the efficacy of potential interventions to prevent and treat epidural-related maternal hyperthermia.
Collapse
Affiliation(s)
- G Chang
- MSk Lab, Imperial College London, London, UK
| | - H Moiteiro Manteigas
- MSk Lab, Imperial College London, London, UK; Theatres and Anaesthetics, Imperial College Healthcare NHS Trust, London, UK
| | | | - C J Mullington
- MSk Lab, Imperial College London, London, UK; Theatres and Anaesthetics, Imperial College Healthcare NHS Trust, London, UK.
| |
Collapse
|
5
|
Isacco L, Lambert C, Siroux J, Boscaro A, Cardenoux C, Julian V, Duclos M, Boirie Y, Pereira B, Ennequin G, Thivel D. Weight loss does not affect the sit-to-stand metabolic cost in adolescents with obesity. Eur J Appl Physiol 2023; 123:2511-2523. [PMID: 37310434 DOI: 10.1007/s00421-023-05247-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 05/31/2023] [Indexed: 06/14/2023]
Abstract
PURPOSE There is considerable interest in simple and effective methods to reduce sitting time and increase energy expenditure, and standing breaks have emerged as a realisable approach in individuals with obesity. The aim of the present study was to determine the extent to which energy expenditure in standing differs from sitting, and whether this energetic and metabolic-related responses are modified following a weight loss program in adolescents with obesity. METHODS After body composition assessment (DXA), cardiorespiratory and metabolic variables were continuously recorded (indirect calorimetry) during 10 min while sitting and then during 5 min standing posture before (n = 21; T1) and at the end of a multidisciplinary intervention (n = 17; T2) in adolescents with obesity. RESULTS Before and after the intervention, energy expenditure and fat oxidation rates were significantly increased in standing compared with sitting. Weight loss did not change the relationship between sitting and standing energy expenditure. Sitting energy expenditure represented 1.0 and 1.1 Metabolic Equivalent of Task at T1 and T2, and increased to 1.1 and 1.2 during standing at T1 and T2, respectively. The percentage of change of android fat mass between T1 and T2 was positively associated with the percentage of change in energy expenditure from sitting to standing at T2. CONCLUSION The vast majority of the adolescents with obesity significantly increased their energy expenditure between sitting and standing, both before and after a weight loss intervention. However, the standing posture did not allow breaking the sedentary threshold. Abdominal fat mass is associated with energic profile.
Collapse
Affiliation(s)
- Laurie Isacco
- Laboratory of the Metabolic Adaptations to Exercise Under Physiological and Pathological Conditions (AME2P), CRNH Auvergne, Clermont Auvergne University, UPR 3533, Clermont-Ferrand, 63171, Aubière cedex, France.
- International Research Chair Health in Motion, Clermont Auvergne University Foundation, Clermont-Ferrand, France.
| | - Céline Lambert
- Biostatistics Unit, DRCI, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Julie Siroux
- Laboratory of the Metabolic Adaptations to Exercise Under Physiological and Pathological Conditions (AME2P), CRNH Auvergne, Clermont Auvergne University, UPR 3533, Clermont-Ferrand, 63171, Aubière cedex, France
| | - Audrey Boscaro
- Laboratory of the Metabolic Adaptations to Exercise Under Physiological and Pathological Conditions (AME2P), CRNH Auvergne, Clermont Auvergne University, UPR 3533, Clermont-Ferrand, 63171, Aubière cedex, France
| | | | - Valérie Julian
- Department of Sport Medicine and Functional Explorations, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Martine Duclos
- International Research Chair Health in Motion, Clermont Auvergne University Foundation, Clermont-Ferrand, France
- Department of Sport Medicine and Functional Explorations, CHU Clermont-Ferrand, Clermont-Ferrand, France
- UMR 1019, INRA, Clermont-Ferrand, France
| | - Yves Boirie
- UMR 1019, INRA, Clermont-Ferrand, France
- Department of Human Nutrition, CHU Clermont-Ferrand, Clermont-Ferrand, France
- CSO-CALORIS, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Bruno Pereira
- Biostatistics Unit, DRCI, CHU Clermont-Ferrand, Clermont-Ferrand, France
| | - Gaël Ennequin
- Laboratory of the Metabolic Adaptations to Exercise Under Physiological and Pathological Conditions (AME2P), CRNH Auvergne, Clermont Auvergne University, UPR 3533, Clermont-Ferrand, 63171, Aubière cedex, France
- International Research Chair Health in Motion, Clermont Auvergne University Foundation, Clermont-Ferrand, France
| | - David Thivel
- Laboratory of the Metabolic Adaptations to Exercise Under Physiological and Pathological Conditions (AME2P), CRNH Auvergne, Clermont Auvergne University, UPR 3533, Clermont-Ferrand, 63171, Aubière cedex, France
- International Research Chair Health in Motion, Clermont Auvergne University Foundation, Clermont-Ferrand, France
- CSO-CALORIS, CHU Clermont-Ferrand, Clermont-Ferrand, France
| |
Collapse
|
6
|
Wolf ST, Folkerts MA, Cottle RM, Daanen HAM, Kenney WL. Metabolism- and sex-dependent critical WBGT limits at rest and during exercise in the heat. Am J Physiol Regul Integr Comp Physiol 2021; 321:R295-R302. [PMID: 34259026 DOI: 10.1152/ajpregu.00101.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Critical environmental limits are environmental thresholds above which heat gain exceeds heat loss and body core temperature (Tc) cannot be maintained at equilibrium. Those limits can be represented as critical wet-bulb globe temperature (WBGTcrit), a validated index that represents the overall thermal environment. Little is known about WBGTcrit at rest and during low-to-moderate intensity exercise, or sex differences in WBGTcrit, in unacclimated young adults. The following hypotheses were tested: 1) WBGTcrit progressively decreases as metabolic heat production (Mnet) increases, 2) no sex differences in WBGTcrit occur at rest, and 3) WBGTcrit is lower during absolute-intensity exercise but higher at relative intensities in women than in men. Thirty-six participants [19 men (M)/17 women (W); 23 ± 4 yr] were tested at rest, during light, absolute-intensity exercise (10 W), or during moderate, relative-intensity exercise [30% maximal oxygen consumption (V̇o2max)] in an environmental chamber. Dry-bulb temperature was clamped as relative humidity or ambient water vapor pressure was increased until an upward inflection was observed in Tc (rectal or esophageal temperature). Sex-aggregated WBGTcrit was lower during 10 W (32.9°C ± 1.7°C, P < 0.0001) and 30% V̇o2max (31.6°C ± 1.1°C, P < 0.0001) exercise versus at rest (35.3°C ± 0.8°C), and lower at 30% V̇o2max versus 10 W (P = 0.01). WBGTcrit was similar between sexes at rest (35.6°C ± 0.8°C vs. 35.0°C ± 0.8°C, P = 0.83), but lower during 10 W (31.9°C ± 1.7°C vs. 34.1°C ± 0.3°C, P < 0.01) and higher during 30% V̇o2max (32.4°C ± 0.8°C vs. 30.8°C ± 0.9°C, P = 0.03) exercise in women versus men. These findings suggest that WBGTcrit decreases as Mnet increases, no sex differences occur in WBGTcrit at rest, and sex differences in WBGTcrit during exercise depend on absolute versus relative intensities.
Collapse
Affiliation(s)
- S Tony Wolf
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania
| | - Mireille A Folkerts
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Rachel M Cottle
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania
| | - Hein A M Daanen
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - W Larry Kenney
- Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania
| |
Collapse
|
7
|
Dynamics of Fat Oxidation from Sitting at Rest to Light Exercise in Inactive Young Humans. Metabolites 2021; 11:metabo11060334. [PMID: 34073688 PMCID: PMC8225068 DOI: 10.3390/metabo11060334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 12/20/2022] Open
Abstract
Societal erosion of daily life low-level physical activity has had a great influence on the obesity epidemic. Given that low fat oxidation is also a risk factor for obesity, we investigated, in a repeated measures design, the dynamics of fat oxidation from a resting state to a light-intensity leg cycling exercise (0–50 watts) in inactive, healthy young adults. Using indirect calorimetry, energy expenditure and the respiratory quotient (RQ) were assessed in a sitting posture at rest and during a cycling exercise in 35 subjects (20 women). The rate of perceived exhaustion (RPE) was assessed using the Borg Scale. During graded leg cycling, the mean RPE did not exceed values corresponding to the exercise being perceived as ‘light’. However, analysis of individual data at 50 watts revealed two distinct subgroups among the subjects: those having RPE values corresponding to the exercise being perceived as ‘very light to light’ and showing no increase in RQ relative to resting levels, as opposed to an increase in RQ in those who perceived the exercise as being ‘somewhat hard to hard’ (p < 0.001). Our study in inactive individuals showing that high fat oxidation was maintained during ‘light-perceived’ physical activity reinforced the potential importance of light physical activity in the prevention of obesity.
Collapse
|
8
|
Luna SV, Pompano LM, Lung'aho M, Gahutu JB, Haas JD. Increased Iron Status during a Feeding Trial of Iron-Biofortified Beans Increases Physical Work Efficiency in Rwandan Women. J Nutr 2020; 150:1093-1099. [PMID: 32006009 PMCID: PMC7198300 DOI: 10.1093/jn/nxaa016] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/22/2019] [Accepted: 01/15/2020] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Iron-biofortified staple foods can improve iron status and resolve iron deficiency. However, whether improved iron status from iron biofortification can improve physical performance remains unclear. OBJECTIVE This study aimed to examine whether changes in iron status from an iron-biofortified bean intervention affect work efficiency. METHODS A total of 125 iron-depleted (ferritin <20 μg/L) female Rwandan university students (18-26 y) were selected from a larger sample randomly assigned to consume iron-biofortified beans (Fe-Bean; 86.1 mg Fe/kg) or conventional beans (control: 50.6 mg Fe/kg) twice daily for 18 wk (average of 314 g beans consumed/d). Blood biomarkers of iron status (primary outcome) and physical work efficiency (secondary outcome) were measured before and after the intervention. Work performed was assessed during 5-min steady-state periods at 0-, 25-, and 40-W workloads using a mechanically braked cycle ergometer. Work efficiency was calculated at 25 W and 40 W as the work accomplished divided by the energy expended at that workload above that expended at 0 W. General linear models were used to evaluate the relation between changes in iron status biomarkers and work efficiency. RESULTS The Fe-Bean intervention had significant positive effects on hemoglobin, serum ferritin, and body iron stores but did not affect work efficiency. However, 18-wk change in hemoglobin was positively related to work efficiency at 40 W in the full sample (n = 119; estimate: 0.24 g/L; 95% CI: 0.01, 0.48 g/L; P = 0.044) and among women who were anemic (hemoglobin <120 g/L) at baseline (n = 43; estimate: 0.64 g/L; 95% CI: 0.05, 1.23 g/L; P = 0.036). Among women who were nonanemic at baseline, change in serum ferritin was positively related to change in work efficiency at 40 W (n = 60; estimate: 0.50 μg/L; 95% CI: 0.06, 0.95 μg/L; P = 0.027). CONCLUSIONS Increasing iron status during an iron-biofortified bean feeding trial improves work efficiency in iron-depleted, sedentary women. This trial was registered at clinicaltrials.gov as NCT01594359.
Collapse
Affiliation(s)
- Sarah V Luna
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Laura M Pompano
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Mercy Lung'aho
- Centro Internacional de Agricultura Tropical-Uganda, Kawanda, Uganda
| | - Jean Bosco Gahutu
- School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Huye, Rwanda
| | - Jere D Haas
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA,Address correspondence to JDH (e-mail: )
| |
Collapse
|
9
|
Mood Responses to Passive and Active Motion Leg Cycling Exercise in Healthy Sedentary Young Adults. Adv Prev Med 2020; 2020:7282013. [PMID: 32181019 PMCID: PMC7066409 DOI: 10.1155/2020/7282013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 12/05/2019] [Accepted: 12/20/2019] [Indexed: 11/20/2022] Open
Abstract
Previous studies suggest that passive motion exercise (PME) may be useful for overcoming exercise limitations associated with a sedentary lifestyle, orthopedic disorders, and various other debilitating conditions. Negative mood response is one of the factors that limit a person's ability to exercise. Therefore, this study tests the hypothesis that the mood response associated with PME is not different than the mood response associated with active motion exercise (AME). Eight women and seven men participated in the study and were administrated the Profile of Mood States (POMS) during modes of PME and AME in a randomized order. Outcome of the POMS consisted of the total mood disturbance score [(feelings of tension + depression + fatigue + anger + confusion) − vigor]. ANOVA was used to determine significance of differences in total mood disturbance, oxygen uptake (V.O2), and middle cerebral blood flow velocity (MCAv) at baseline and immediately after 30-minute conditions of PME and AME. Postexercise total mood disturbance score was significantly decreased for both conditions (PME baseline 29.2 ± 5.2 vs. postexercise 16.4 ± 6.8, P < 0.05) and AME baseline 22.4 ± 4.4 vs. postexercise 13.1 ± 5.2, P < 0.05). These senses of changes in feelings were associated with significant physiological increases in V.O2 and MCAv during both PME and AME (P < 0.05). These results demonstrate that physiological and mood responses to passive and active motion cycling exercise are not different. Future studies should determine whether passive motion cycling exercise is a useful preventive medicine strategy for overcoming various disease-related exercise limitations and counteracting the adverse effects of sedentary lifestyles.
Collapse
|
10
|
Faulhaber M, Pramsohler S, Rausch L, Menz V. Cardiorespiratory and Metabolic Responses During Graded Exercise in Normobaric and Hypobaric Hypoxia. High Alt Med Biol 2020; 21:70-75. [PMID: 31923367 DOI: 10.1089/ham.2019.0094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background: The study investigated submaximal exercise responses during an acute exposure to normobaric hypoxia (NH) versus hypobaric hypoxia (HH) focusing on different exercise intensities. Methods: Eight recreationally trained male subjects (age 23 ± 3 years) performed submaximal cycling exercise at three different intensity levels (100, 150, and 200 W) in NH (simulated altitude 3150 m) and HH (terrestrial high altitude, 3150 m) in a cross-over study design. Cardiorespiratory parameter, blood lactate concentration, and ratings of perceived exertion were determined at each intensity level. Results: Cardiorespiratory parameters, arterial oxygen saturation, and ratings of perceived exertion did not differ between NH and HH except for the higher ventilatory equivalent for oxygen in HH compared to NH (25.9 ± 1.3 vs. 24.6 ± 1.0 at 100 W, 28.0 ± 1.6 vs. 27.1 ± 1.6 at 150 W, 32.1 ± 3.9 vs. 31.3 ± 3.6 at 200 W, p = 0.03). Blood lactate concentration tended to be higher in HH compared to NH (1.8 ± 0.9 mmol/L vs. 1.7 ± 0.8 mmol/L at 100 W, 3.2 ± 1.8 mmol/L vs. 2.8 ± 1.6 mmol/L at 150 W, 6.0 ± 3.1 mmol/L vs. 5.5 ± 3.0 mmol/L at 200 W, p = 0.08) with a significant interaction effect for exercise intensity (p = 0.02). Conclusions: Cycling during acute exposure to NH appears to result in equivalent cardiorespiratory responses to HH. The more pronounced lactate accumulation in HH should be a topic of future research.
Collapse
Affiliation(s)
- Martin Faulhaber
- Department of Sport Science, University Innsbruck, Innsbruck, Austria.,Austrian Society of Alpine and High Altitude Medicine, Mieming, Austria
| | - Stephan Pramsohler
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, Bad Aibling, Germany
| | - Linda Rausch
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, Bad Aibling, Germany
| | - Verena Menz
- Department of Sport Science, University Innsbruck, Innsbruck, Austria
| |
Collapse
|
11
|
Coggan AR, Broadstreet SR, Mahmood K, Mikhalkova D, Madigan M, Bole I, Park S, Leibowitz JL, Kadkhodayan A, Thomas DP, Thies D, Peterson LR. Dietary Nitrate Increases VO 2peak and Performance but Does Not Alter Ventilation or Efficiency in Patients With Heart Failure With Reduced Ejection Fraction. J Card Fail 2017; 24:65-73. [PMID: 28916479 DOI: 10.1016/j.cardfail.2017.09.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/01/2017] [Accepted: 09/06/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND Patients with heart failure with reduced ejection fraction (HFrEF) exhibit lower efficiency, dyspnea, and diminished peak oxygen uptake (VO2peak) during exercise. Dietary nitrate (NO3-), a source of nitric oxide (NO), has improved these measures in some studies of other populations. We determined the effects of acute NO3- ingestion on exercise responses in 8 patients with HFrEF using a randomized, double-blind, placebo-controlled, crossover design. METHODS AND RESULTS Plasma NO3-, nitrite (NO2-), and breath NO were measured at multiple time points and respiratory gas exchange was determined during exercise after ingestion of beetroot juice containing or devoid of 11.2 mmol of NO3-. NO3- intake increased (P < .05-0.001) plasma NO3- and NO2- and breath NO by 1469 ± 245%, 105 ± 34%, and 60 ± 18%, respectively. Efficiency and ventilation during exercise were unchanged. However, NO3- ingestion increased (P < .05) VO2peak by 8 ± 2% (ie, from 21.4 ± 2.1 to 23.0 ± 2.3 mL.min-1.kg-1). Time to fatigue improved (P < .05) by 7 ± 3 % (ie, from 582 ± 84 to 612 ± 81 seconds). CONCLUSIONS Acute dietary NO3- intake increases VO2peak and performance in patients with HFrEF. These data, in conjunction with our recent data demonstrating that dietary NO3- also improves muscle contractile function, suggest that dietary NO3- supplementation may be a valuable means of enhancing exercise capacity in this population.
Collapse
Affiliation(s)
- Andrew R Coggan
- Department of Kinesiology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana; Department of Cellular and Integrative Physiology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana; Department of Radiology, Washington University School of Medicine, St. Louis, Missouri.
| | - Seth R Broadstreet
- Department of Kinesiology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana
| | - Kiran Mahmood
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Deana Mikhalkova
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Michael Madigan
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Indra Bole
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Soo Park
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Joshua L Leibowitz
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Ana Kadkhodayan
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Deepak P Thomas
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Dakkota Thies
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - Linda R Peterson
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri; Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| |
Collapse
|
12
|
Fares EJ, Isacco L, Monnard CR, Miles-Chan JL, Montani JP, Schutz Y, Dulloo AG. Reliability of low-power cycling efficiency in energy expenditure phenotyping of inactive men and women. Physiol Rep 2017; 5:e13233. [PMID: 28507164 PMCID: PMC5430120 DOI: 10.14814/phy2.13233] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 11/30/2022] Open
Abstract
Standardized approaches to assess human energy expenditure (EE) are well defined at rest and at moderate to high-intensity exercise, but not at light intensity physical activities energetically comparable with those of daily life (i.e., 1.5-4 times the resting EE, i.e., 1.5-4 METs). Our aim was to validate a graded exercise test for assessing the energy cost of low-intensity dynamic work in physically inactive humans, that is, those who habitually do not meet the guidelines for moderate-to-vigorous aerobic physical activity levels. In healthy and inactive young men and women (n = 55; aged 18-32 years), EE was assessed in the overnight-fasted state by indirect calorimetry at rest and during graded cycling between 5 and 50W for 5 min at each power output on a bicycle ergometer. Repeatability was investigated on three separate days, and the effect of cadence was investigated in the range of 40-90 rpm. Within the low power range of cycling, all subjects perceived the exercise test as "light" on the Borg scale, the preferred cadence being 60 rpm. A strong linearity of the EE-power relationship was observed between 10 and 50 W for each individual (r > 0.98), and the calculation of delta efficiency (DE) from the regression slope indicated that DE was similar in men and women (~29%). DE showed modest inter-individual variability with a coefficient of variation (CV) of 11%, and a low intra-individual variability with a CV of ~ 5%. No habituation or learning effect was observed in DE across days. In conclusion, the assessment of the efficiency of low power cycling by linear regression - and conducted within the range of EE observed for low-intensity movements of everyday life (1.5-4 METs) - extends the capacity for metabolic phenotyping in the inactive population.
Collapse
Affiliation(s)
- Elie-Jacques Fares
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| | - Laurie Isacco
- EA3920 and EPSI platform, Bourgogne Franche-Comté University, Besançon, France
| | - Cathriona R Monnard
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| | | | - Jean-Pierre Montani
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| | - Yves Schutz
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| | - Abdul G Dulloo
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| |
Collapse
|
13
|
Peterman JE, Wright KP, Melanson EL, Kram R, Byrnes WC. Motor-Driven (Passive) Cycling: A Potential Physical Inactivity Countermeasure? Med Sci Sports Exerc 2016; 48:1821-8. [PMID: 27054677 DOI: 10.1249/mss.0000000000000947] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UNLABELLED We have previously shown that motor-driven (passive) stationary cycling elevates energy expenditure (EE). PURPOSE This study aimed to quantify how acute passive cycling affects glucose and insulin responses to an oral glucose tolerance test (OGTT) and basic cognition compared with sitting and moderate-intensity active cycling. METHODS Twenty-four physically inactive healthy males completed three trials in randomized order involving 30-min conditions of sitting, passive cycling, and moderate-intensity cycling. During each condition, EE was measured, and participants performed cognitive tests. After each condition, a 2-h OGTT was performed. RESULTS EE was significantly higher during the cycling conditions compared with sitting (1.36 ± 0.58 and 6.50 ± 1.73 kcal·min greater than sitting for passive and moderate-intensity, respectively). A significant correlation was found between body fat percentage and postsitting OGTT 2-h postplasma glucose (r = 0.30, P < 0.05); thus, participants were divided into lean (n = 11) and nonlean (n = 13) groups. In the nonlean group, compared with sitting, passive cycling lowered 2-h postplasma glucose (7.7 ± 1.3 vs 6.9 ± 1.6 mmol·L, respectively, P < 0.05), and the Matsuda whole-body insulin sensitivity index (WBISI) was higher (2.74 ± 0.86 vs 3.36 ± 1.08, P < 0.05). In addition, passive and moderate-intensity cycling had similar beneficial effects on 2-h postplasma glucose and WBISI. Cognitive performance did not significantly differ between the sitting and passive cycling conditions. CONCLUSIONS Two-hour postplasma glucose was lower and WBISI after acute passive cycling was higher in nonlean participants. Given that and the increase in EE without changes in cognitive performance, we propose passive cycling as a promising intervention to counteract some of the deleterious effects of prolonged sitting in the workplace.
Collapse
Affiliation(s)
- James E Peterman
- 1Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO; 2Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO; and 3Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO
| | | | | | | | | |
Collapse
|
14
|
Hatamoto Y, Yamada Y, Higaki Y, Tanaka H. A novel approach for measuring energy expenditure of a single sit-to-stand movement. Eur J Appl Physiol 2016; 116:997-1004. [PMID: 27017496 DOI: 10.1007/s00421-016-3355-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 03/09/2016] [Indexed: 11/26/2022]
Abstract
PURPOSE The purpose of this study was to quantify the energy expenditure (EE) of a sit-to-stand (STS) movement using a recently developed method and to examine the relationship between physical characteristics and the physiological demands of STS. METHODS Nineteen participants completed a multi-stage test at different STS frequencies of 6, 10, 15, 20 and 30 repetitions per minute. The expired gas, heart rate (HR) and rating of perceived exertion (RPE) were measured. The relationship between EE and STS frequency was obtained and the slope of the regression was quantified as the EE of an STS. RESULTS The gross EE and HR increased linearly as the STS frequency increased in all participants. The net EE of an STS was 0.92 ± 0.37 kJ. The EE of an STS increased as the height and weight increased, and these relationships were well fit by quadratic regression. The metabolic equivalent (Met) of performing 15 STSs per minute was 4.3 ± 1.0 Mets and RPE was 12 ± 1 over a total of 20. CONCLUSION This study demonstrated that the EE of an instantaneous movement can be quantified by relating the gross EE and different frequencies of movement. Using this method, we quantified the EE of an STS, which varied depending on participants' anthropometrics. Mets of repetitive STS movement ranged from 2.6 to 7.2. This physiological profile is useful when performing repetitive STS movements as a form of exercise.
Collapse
Affiliation(s)
- Yoichi Hatamoto
- The Fukuoka University Institute for Physical Activity, Fukuoka, Japan
| | - Yosuke Yamada
- The Fukuoka University Institute for Physical Activity, Fukuoka, Japan
- Department of Nutritional Science, National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan
| | - Yasuki Higaki
- The Fukuoka University Institute for Physical Activity, Fukuoka, Japan
- Graduate School of Sports and Health Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan
| | - Hiroaki Tanaka
- The Fukuoka University Institute for Physical Activity, Fukuoka, Japan.
- Graduate School of Sports and Health Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan.
| |
Collapse
|
15
|
Broskey NT, Boss A, Fares EJ, Greggio C, Gremion G, Schlüter L, Hans D, Kreis R, Boesch C, Amati F. Exercise efficiency relates with mitochondrial content and function in older adults. Physiol Rep 2015; 3:3/6/e12418. [PMID: 26059033 PMCID: PMC4510622 DOI: 10.14814/phy2.12418] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Chronic aerobic exercise has been shown to increase exercise efficiency, thus allowing less energy expenditure for a similar amount of work. The extent to which skeletal muscle mitochondria play a role in this is not fully understood, particularly in an elderly population. The purpose of this study was to determine the relationship of exercise efficiency with mitochondrial content and function. We hypothesized that the greater the mitochondrial content and/or function, the greater would be the efficiencies. Thirty-eight sedentary (S, n = 23, 10F/13M) or athletic (A, n = 15, 6F/9M) older adults (66.8 ± 0.8 years) participated in this cross sectional study. O2peak was measured with a cycle ergometer graded exercise protocol (GXT). Gross efficiency (GE, %) and net efficiency (NE, %) were estimated during a 1-h submaximal test (55% O2peak). Delta efficiency (DE, %) was calculated from the GXT. Mitochondrial function was measured as ATPmax (mmol/L/s) during a PCr recovery protocol with 31P-MR spectroscopy. Muscle biopsies were acquired for determination of mitochondrial volume density (MitoVd, %). Efficiencies were 17% (GE), 14% (NE), and 16% (DE) higher in A than S. MitoVD was 29% higher in A and ATPmax was 24% higher in A than in S. All efficiencies positively correlated with both ATPmax and MitoVd. Chronically trained older individuals had greater mitochondrial content and function, as well as greater exercise efficiencies. GE, NE, and DE were related to both mitochondrial content and function. This suggests a possible role of mitochondria in improving exercise efficiency in elderly athletic populations and allowing conservation of energy at moderate workloads.
Collapse
Affiliation(s)
- Nicholas T Broskey
- Department of Physiology, School of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Andreas Boss
- Department of Clinical Research & Institute of Interventional, Diagnostic and Pediatric Radiology, University of Bern, Bern, Switzerland
| | - Elie-Jacques Fares
- Department of Physiology, School of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Chiara Greggio
- Department of Physiology, School of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Gerald Gremion
- Sports Medicine Unit, University Hospital, Lausanne, Switzerland
| | - Leo Schlüter
- Service of Cardiology, University Hospital, Lausanne, Switzerland
| | - Didier Hans
- Center for Bone Disease, Bone & Joint Department, University Hospital, Lausanne, Switzerland
| | - Roland Kreis
- Department of Clinical Research & Institute of Interventional, Diagnostic and Pediatric Radiology, University of Bern, Bern, Switzerland
| | - Chris Boesch
- Department of Clinical Research & Institute of Interventional, Diagnostic and Pediatric Radiology, University of Bern, Bern, Switzerland
| | - Francesca Amati
- Department of Physiology, School of Biology and Medicine, University of Lausanne, Lausanne, Switzerland Sports Medicine Unit, University Hospital, Lausanne, Switzerland
| |
Collapse
|
16
|
Dulloo AG, Schutz Y. Adaptive Thermogenesis in Resistance to Obesity Therapies: Issues in Quantifying Thrifty Energy Expenditure Phenotypes in Humans. Curr Obes Rep 2015; 4:230-40. [PMID: 26627218 DOI: 10.1007/s13679-015-0156-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Dieting and exercise are likely to remain the core approaches in the management of obesity in the foreseeable future despite their well-documented failures for achieving long-term weight loss. Explanations for such poor prognosis are centered on patient's self-regulatory failure and lack of compliance to the prescribed diet or exercise regimen. While a role for physiological adaptations leading to diminished rates of heat production has also been advocated, there are considerable uncertainties about the quantitative importance of such regulated heat production (i.e., adaptive thermogenesis) to the less-than-expected weight loss and ease for weight regain. This paper first reviews the most compelling evidence of what is often considered as weight loss-induced adaptive thermogenesis in various compartments of daily energy expenditure. It then discusses the major limitations and issues in quantifying such thrifty energy expenditure phenotypes and underscores the plausibility of diminished core temperature as a thrifty metabolic trait in resistance to weight loss. Although an accurate quantification of adaptive thermogenesis will have to await the applications of deep body composition phenotyping and better discrimination of physical activity energy expenditures, the magnitude of diminished energy expenditure in response to weight loss in certain individuals is large enough to support the concept that adaptive thermogenesis contribute importantly to their resistance to obesity therapies.
Collapse
Affiliation(s)
- Abdul G Dulloo
- Department of Medicine/Physiology, University of Fribourg, Chemin du musée 5, 1700, Fribourg, Switzerland.
| | - Yves Schutz
- Department of Medicine/Physiology, University of Fribourg, Chemin du musée 5, 1700, Fribourg, Switzerland
| |
Collapse
|
17
|
Sarafian D, Miles-Chan JL, Yepuri G, Montani JP, Schutz Y, Dulloo AG. A standardized approach to study human variability in isometric thermogenesis during low-intensity physical activity. Front Physiol 2013; 4:155. [PMID: 23847539 PMCID: PMC3696839 DOI: 10.3389/fphys.2013.00155] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 06/10/2013] [Indexed: 11/13/2022] Open
Abstract
UNLABELLED Limitations of current methods: The assessment of human variability in various compartments of daily energy expenditure (EE) under standardized conditions is well defined at rest [as basal metabolic rate (BMR) and thermic effect of feeding (TEF)], and currently under validation for assessing the energy cost of low-intensity dynamic work. However, because physical activities of daily life consist of a combination of both dynamic and isometric work, there is also a need to develop standardized tests for assessing human variability in the energy cost of low-intensity isometric work. EXPERIMENTAL OBJECTIVES Development of an approach to study human variability in isometric thermogenesis by incorporating a protocol of intermittent leg press exercise of varying low-intensity isometric loads with measurements of EE by indirect calorimetry. RESULTS EE was measured in the seated position with the subject at rest or while intermittently pressing both legs against a press-platform at 5 low-intensity isometric loads (+5, +10, +15, +20, and +25 kg force), each consisting of a succession of 8 cycles of press (30 s) and rest (30 s). EE, integrated over each 8-min period of the intermittent leg press exercise, was found to increase linearly across the 5 isometric loads with a correlation coefficient (r) > 0.9 for each individual. The slope of this EE-Load relationship, which provides the energy cost of this standardized isometric exercise expressed per kg force applied intermittently (30 s in every min), was found to show good repeatability when assessed in subjects who repeated the same experimental protocol on 3 separate days: its low intra-individual coefficient of variation (CV) of ~ 10% contrasted with its much higher inter-individual CV of 35%; the latter being mass-independent but partly explained by height. CONCLUSION This standardized approach to study isometric thermogenesis opens up a new avenue for research in EE phenotyping and metabolic predisposition to obesity.
Collapse
Affiliation(s)
- Delphine Sarafian
- Department of Medicine/Physiology, University of Fribourg Fribourg, Switzerland
| | | | | | | | | | | |
Collapse
|