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Pryor JL, Sweet D, Rosbrook P, Qiao J, Hess HW, Looney DP. Resistance Training in the Heat: Mechanisms of Hypertrophy and Performance Enhancement. J Strength Cond Res 2024; 38:1350-1357. [PMID: 38775794 DOI: 10.1519/jsc.0000000000004815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
ABSTRACT Pryor, JL, Sweet, D, Rosbrook, P, Qiao, J, Hess, HW, and Looney, DP. Resistance training in the heat: Mechanisms of hypertrophy and performance enhancement. J Strength Cond Res 38(7): 1350-1357, 2024-The addition of heat stress to resistance exercise or heated resistance exercise (HRE) is growing in popularity as emerging evidence indicates altered neuromuscular function and an amplification of several mechanistic targets of protein synthesis. Studies demonstrating increased protein synthesis activity have shown temperature-dependent mammalian target of rapamycin phosphorylation, supplemental calcium release, augmented heat shock protein expression, and altered immune and hormone activity. These intriguing observations have largely stemmed from myotube, isolated muscle fiber, or rodent models using passive heating alone or in combination with immobilization or injury models. A growing number of translational studies in humans show comparable results employing local tissue or whole-body heat with and without resistance exercise. While few, these translational studies are immensely valuable as they are most applicable to sport and exercise. As such, this brief narrative review aims to discuss evidence primarily from human HRE studies detailing the neuromuscular, hormonal, and molecular responses to HRE and subsequent strength and hypertrophy adaptations. Much remains unknown in this exciting new area of inquiry from both a mechanistic and functional perspective warranting continued research.
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Affiliation(s)
- J Luke Pryor
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York; and
| | - Daniel Sweet
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York; and
| | - Paul Rosbrook
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York; and
| | - JianBo Qiao
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York; and
| | - Hayden W Hess
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York; and
| | - David P Looney
- United States Army Research Institute of Environmental Medicine (USARIEM), Natick, Massachusetts
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Bachraty JP, Qiao J, Powers ES, Vandermark LW, Pryor JL, Pryor RR. Plateau in Core Temperature during Shorter but Not Longer Work/Rest Cycles in Heat. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2024; 21:371. [PMID: 38541370 PMCID: PMC10970706 DOI: 10.3390/ijerph21030371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/12/2024] [Accepted: 03/18/2024] [Indexed: 04/09/2024]
Abstract
This study compared physiological responses to two work/rest cycles of a 2:1 work-to-rest ratio in a hot environment. In a randomized crossover design, fourteen participants completed 120 min of walking and rest in the heat (36.3 ± 0.6 °C, 30.2 ± 4.0% relative humidity). Work/rest cycles were (1) 40 min work/20 min rest [40/20], or (2) 20 min work/10 min rest [20/10], both completing identical work. Core temperature (Tc), skin temperature (Tsk), heart rate (HR), nude body mass, and perception of work were collected. Comparisons were made between trials at equal durations of work using three-way mixed model ANOVA. Tc plateaued in [20/10] during the second hour of work (p = 0.93), while Tc increased in [40/20] (p < 0.01). There was no difference in maximum Tc ([40/20]: 38.08 ± 0.35 °C, [20/10]: 37.99 ± 0.27 °C, p = 0.22) or end-of-work Tsk ([40/20]: 36.1 ± 0.8 °C, [20/10]: 36.0 ± 0.7 °C, p = 0.45). End-of-work HR was greater in [40/20] (145 ± 25 b·min-1) compared to [20/10] (141 ± 27 b·min-1, p = 0.04). Shorter work/rest cycles caused a plateau in Tc while longer work/rest cycles resulted in a continued increase in Tc throughout the work, indicating that either work structure could be used during shorter work tasks, while work greater than 2 h in duration may benefit from shorter work/rest cycles to mitigate hyperthermia.
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Affiliation(s)
| | | | | | | | | | - Riana R. Pryor
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY 14214, USA (J.Q.); (E.S.P.)
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Rosbrook P, Sweet D, Qiao J, Looney DP, Margolis LM, Hostler D, Pryor RR, Pryor JL. Heat stress increases carbohydrate oxidation rates and oxygen uptake during prolonged load carriage exercise. Temperature (Austin) 2024; 11:170-181. [PMID: 38846526 PMCID: PMC11152092 DOI: 10.1080/23328940.2024.2322920] [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: 08/17/2023] [Accepted: 02/19/2024] [Indexed: 06/09/2024] Open
Abstract
Military missions are conducted in a multitude of environments including heat and may involve walking under load following severe exertion, the metabolic demands of which may have nutritional implications for fueling and recovery planning. Ten males equipped a military pack loaded to 30% of their body mass and walked in 20°C/40% relative humidity (RH) (TEMP) or 37°C/20% RH (HOT) either continuously (CW) for 90 min at the first ventilatory threshold or mixed walking (MW) with unloaded running intervals above the second ventilatory threshold between min 35 and 55 of the 90 min bout. Pulmonary gas, thermoregulatory, and cardiovascular variables were analyzed following running intervals. Final rectal temperature (MW: p < 0.001, g = 3.81, CW: p < 0.001, g = 4.04), oxygen uptake, cardiovascular strain, and energy expenditure were higher during HOT trials (p ≤ 0.05) regardless of exercise type. Both HOT trials elicited higher final carbohydrate oxidation (CHOox) than TEMP CW at min 90 (HOT MW: p < 0.001, g = 1.45, HOT CW: p = 0.009, g = 0.67) and HOT MW CHOox exceeded TEMP MW at min 80 and 90 (p = 0.049, g = 0.60 and p = 0.024, g = 0.73, respectively). There were no within-environment differences in substrate oxidation indicating that severe exertion work cycles did not produce a carryover effect during subsequent loaded walking. The rate of CHOox during 90 minutes of load carriage in the heat appears to be primarily affected by accumulated thermal load.
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Affiliation(s)
- Paul Rosbrook
- Center for Research & Education in Special Environments, University at Buffalo, Buffalo, USA
| | - Daniel Sweet
- Center for Research & Education in Special Environments, University at Buffalo, Buffalo, USA
| | - JianBo Qiao
- Center for Research & Education in Special Environments, University at Buffalo, Buffalo, USA
| | - David P. Looney
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, USA
| | - Lee M. Margolis
- Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, USA
| | - David Hostler
- Center for Research & Education in Special Environments, University at Buffalo, Buffalo, USA
| | - Riana R. Pryor
- Center for Research & Education in Special Environments, University at Buffalo, Buffalo, USA
| | - J. Luke Pryor
- Center for Research & Education in Special Environments, University at Buffalo, Buffalo, USA
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Ashley CD, Lopez RM, Tritsch AJ. Football Practices in Hot Environments Impact Subsequent Days' Hydration. J Strength Cond Res 2024; 38:90-96. [PMID: 37815236 DOI: 10.1519/jsc.0000000000004583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
ABSTRACT Ashley, CD, Lopez, RM, and Tritsch, AJ. Football practices in hot environments impact subsequent days' hydration. J Strength Cond Res 38(1): 90-96, 2024-The impact of proper hydration to prevent exertional heat illness in American football has not been evaluated during high school preseason football practices in a hot environment (wet-bulb globe temperature = 31.3 ± 1.8° C). The purposes of this study were to examine the accuracy of urinary hydration measures to assess body mass (BM) changes and to examine carryover effects of consecutive practices by comparing postpractice with the next prepractice values. Before and after each of 7 outdoor practices, 31 male high school football players (age = 16 ± 1 years, height = 181.2 ± 12.0 cm, BM = 85.7 ± 19.1 kg, body mass index = 20.8 ± 1.8) provided a urine sample and were weighed to assess hydration. Sensitivity and specificity of urine color (Ucol) and urine-specific gravity (USG) to determine BM changes were determined using receiver operating characteristic (ROC) analysis. Paired samples t -tests assessed carryover effects between practices. Repeated-measures analysis of variance assessed carryover effects across practices. Significance was set at p < 0.05. Sensitivity and specificity for using Ucol or USG to determine BM changes was not significant. For Ucol, there was a carryover effect from practice numbers 2 to 3, 6 to 7 am , 7 am to 7 pm ( p < 0.001 for all), and 10 to 11 ( p = 0.004); most with less than 24 hours between practices. The %BM loss (%BML) was significantly greater ( p = 0.001 to 0.024) after 2-a-day practices. Effects of previous days' exercise in the heat, as evidenced by higher Ucol and %BL, are greater after 2-a-day practices, which occurred on later practice days. Athletes must replenish fluids during and between practices to remain euhydrated.
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Affiliation(s)
- Candi D Ashley
- Department of Educational and Psychological Studies, University of South Florida, Tampa, Florida; and
| | - Rebecca M Lopez
- School of Physical Therapy and Rehabilitation Sciences, University of South Florida, Tampa, Florida
| | - Amanda J Tritsch
- School of Physical Therapy and Rehabilitation Sciences, University of South Florida, Tampa, Florida
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O'Connor FK, Doering TM, Minett GM, Reaburn PR, Bartlett JD, Coffey VG. Effect of Divergent Solar Radiation Exposure With Outdoor Versus Indoor Training in the Heat: Implications for Performance. J Strength Cond Res 2022; 36:1622-1628. [DOI: 10.1519/jsc.0000000000003706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Morrissey MC, Casa DJ, Brewer GJ, Adams WM, Hosokawa Y, Benjamin CL, Grundstein AJ, Hostler D, McDermott BP, McQuerry ML, Stearns RL, Filep EM, DeGroot DW, Fulcher J, Flouris AD, Huggins RA, Jacklitsch BL, Jardine JF, Lopez RM, McCarthy RB, Pitisladis Y, Pryor RR, Schlader ZJ, Smith CJ, Smith DL, Spector JT, Vanos JK, Williams WJ, Vargas NT, Yeargin SW. Heat Safety in the Workplace: Modified Delphi Consensus to Establish Strategies and Resources to Protect the US Workers. GEOHEALTH 2021; 5:e2021GH000443. [PMID: 34471788 PMCID: PMC8388206 DOI: 10.1029/2021gh000443] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/08/2021] [Accepted: 06/11/2021] [Indexed: 06/04/2023]
Abstract
The purpose of this consensus document was to develop feasible, evidence-based occupational heat safety recommendations to protect the US workers that experience heat stress. Heat safety recommendations were created to protect worker health and to avoid productivity losses associated with occupational heat stress. Recommendations were tailored to be utilized by safety managers, industrial hygienists, and the employers who bear responsibility for implementing heat safety plans. An interdisciplinary roundtable comprised of 51 experts was assembled to create a narrative review summarizing current data and gaps in knowledge within eight heat safety topics: (a) heat hygiene, (b) hydration, (c) heat acclimatization, (d) environmental monitoring, (e) physiological monitoring, (f) body cooling, (g) textiles and personal protective gear, and (h) emergency action plan implementation. The consensus-based recommendations for each topic were created using the Delphi method and evaluated based on scientific evidence, feasibility, and clarity. The current document presents 40 occupational heat safety recommendations across all eight topics. Establishing these recommendations will help organizations and employers create effective heat safety plans for their workplaces, address factors that limit the implementation of heat safety best-practices and protect worker health and productivity.
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Affiliation(s)
- Margaret C. Morrissey
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - Douglas J. Casa
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - Gabrielle J. Brewer
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - William M. Adams
- Department of KinesiologyUniversity of North Carolina at GreensboroGreensboroNCUSA
| | - Yuri Hosokawa
- Faculty of Sports SciencesWaseda UniversitySaitamaJapan
| | | | | | - David Hostler
- Department of Exercise and Nutrition SciencesCenter for Research and Education in Special EnvironmentsBuffaloNYUSA
| | - Brendon P. McDermott
- Department of Health, Human Performance and RecreationUniversity of ArkansasFayettevilleARUSA
| | | | - Rebecca L. Stearns
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - Erica M. Filep
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - David W. DeGroot
- Fort Benning Heat CenterMartin Army Community HospitalFort BenningGAUSA
| | | | - Andreas D. Flouris
- Department of Exercise ScienceFAME LaboratoryUniversity of ThessalyTrikalaGreece
| | - Robert A. Huggins
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | | | - John F. Jardine
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - Rebecca M. Lopez
- School of Physical Therapy & Rehabilitation SciencesMorsani College of MedicineUniversity of South FloridaTampaFLUSA
| | | | - Yannis Pitisladis
- Collaborating Centre of Sports MedicineUniversity of BrightonBrightonUK
| | - Riana R. Pryor
- Department of Exercise and Nutrition SciencesCenter for Research and Education in Special EnvironmentsBuffaloNYUSA
| | - Zachary J. Schlader
- Department of KinesiologySchool of Public HealthIndiana UniversityBloomingtonIAUSA
| | - Caroline J. Smith
- Department of Health and Exercise ScienceAppalachian State UniversityBooneNCUSA
| | - Denise L. Smith
- Department of Health and Human Physiological SciencesFirst Responder Health and Safety LaboratorySkidmore CollegeSaratoga SpringsNYUSA
| | - June T. Spector
- Department of Environmental and Occupational Health SciencesSchool of Public HealthUniversity of WashingtonSeattleWAUSA
| | | | - W. Jon Williams
- Centers for Disease Control and Prevention (CDC)National Personal Protective Technology Laboratory (NPPTL)National Institute for Occupational Safety and Health (NIOSH)PittsburghPAUSA
| | - Nicole T. Vargas
- Faculty of Health SciencesUniversity of SydneySydneyNSWAustralia
| | - Susan W. Yeargin
- Department of Exercise ScienceArnold School of Public HealthUniversity of South CarolinaColumbiaSCUSA
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Pryor RR, Pryor JL, Vandermark LW, Adams EL, Brodeur RM, Armstrong LE, Lee EC, Maresh CM, Casa DJ. Short term heat acclimation reduces heat strain during a first, but not second, consecutive exercise-heat exposure. J Sci Med Sport 2021; 24:768-773. [DOI: 10.1016/j.jsams.2021.03.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 03/15/2021] [Accepted: 03/31/2021] [Indexed: 11/15/2022]
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Adams WM, Hosokawa Y, Casa DJ, Périard JD, Racinais S, Wingo JE, Yeargin SW, Scarneo-Miller SE, Kerr ZY, Belval LN, Alosa D, Csillan D, LaBella C, Walker L. Roundtable on Preseason Heat Safety in Secondary School Athletics: Heat Acclimatization. J Athl Train 2021; 56:352-361. [PMID: 33878177 DOI: 10.4085/1062-6050-596-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To provide best-practice recommendations for developing and implementing heat-acclimatization strategies in secondary school athletics. DATA SOURCES An extensive literature review on topics related to heat acclimatization and heat acclimation was conducted by a group of content experts. Using the Delphi method, action-oriented recommendations were developed. CONCLUSIONS A period of heat acclimatization consisting of ≥14 consecutive days should be implemented at the start of fall preseason training or practices for all secondary school athletes to mitigate the risk of exertional heat illness. The heat-acclimatization guidelines should outline specific actions for secondary school athletics personnel to use, including the duration of training, the number of training sessions permitted per day, and adequate rest periods in a cool environment. Further, these guidelines should include sport-specific and athlete-specific recommendations, such as phasing in protective equipment and reintroducing heat acclimatization after periods of inactivity. Heat-acclimatization guidelines should be clearly detailed in the secondary school's policy and procedures manual and disseminated to all stakeholders. Heat-acclimatization guidelines, when used in conjunction with current best practices surrounding the prevention, management, and care of secondary school student-athletes with exertional heat stroke, will optimize their health and safety.
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Affiliation(s)
- William M Adams
- Hydration, Environment, and Thermal Stress Lab, Department of Kinesiology, University of North Carolina at Greensboro
| | - Yuri Hosokawa
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
| | - Douglas J Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs
| | - Julien D Périard
- Research Institute for Sport and Exercise, University of Canberra, Bruce, Australia
| | - Sebastien Racinais
- Research and Scientific Support Department, ASPETAR Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | | | - Susan W Yeargin
- Department of Exercise Science, University of South Carolina, Columbia
| | | | - Zachary Y Kerr
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill
| | - Luke N Belval
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas
| | - Denise Alosa
- Athletic Medicine, South Burlington School District, Burlington, VT.,College of Nursing and Health Science, University of Vermont, Burlington
| | - David Csillan
- Department of Physical Therapy, Princeton Orthopedic Associates, NJ
| | - Cynthia LaBella
- Department of Pediatrics, Northwestern University Feinberg School of Medicine Institute for Sports Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, IL
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Chapman CL, Hess HW, Lucas RAI, Glaser J, Saran R, Bragg-Gresham J, Wegman DH, Hansson E, Minson CT, Schlader ZJ. Occupational heat exposure and the risk of chronic kidney disease of nontraditional origin in the United States. Am J Physiol Regul Integr Comp Physiol 2021; 321:R141-R151. [PMID: 34161738 DOI: 10.1152/ajpregu.00103.2021] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Occupational heat exposure is linked to the development of kidney injury and disease in individuals who frequently perform physically demanding work in the heat. For instance, in Central America, an epidemic of chronic kidney disease of nontraditional origin (CKDnt) is occurring among manual laborers, whereas potentially related epidemics have emerged in India and Sri Lanka. There is growing concern that workers in the United States suffer with CKDnt, but reports are limited. One of the leading hypotheses is that repetitive kidney injury caused by physical work in the heat can progress to CKDnt. Whether heat stress is the primary causal agent or accelerates existing underlying pathology remains contested. However, the current evidence supports that heat stress induces tubular kidney injury, which is worsened by higher core temperatures, dehydration, longer work durations, muscle damaging exercise, and consumption of beverages containing high levels of fructose. The purpose of this narrative review is to identify occupations that may place US workers at greater risk of kidney injury and CKDnt. Specifically, we reviewed the scientific literature to characterize the demographics, environmental conditions, physiological strain (i.e., core temperature increase, dehydration, heart rate), and work durations in sectors typically experiencing occupational heat exposure, including farming, wildland firefighting, landscaping, and utilities. Overall, the surprisingly limited available evidence characterizing occupational heat exposure in US workers supports the need for future investigations to understand this risk of CKDnt.
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Affiliation(s)
| | - Hayden W Hess
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Rebekah A I Lucas
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Jason Glaser
- La Isla Network, Washington, D.C.,Responsible Business Center at Birkbeck, University of London, London, United Kingdom
| | - Rajiv Saran
- Division of Nephrology and the Kidney Epidemiology and Cost Center, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan.,Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, Michigan
| | - Jennifer Bragg-Gresham
- Division of Nephrology and the Kidney Epidemiology and Cost Center, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
| | - David H Wegman
- Department of Epidemiology, University of Massachusetts Lowell, Lowell, Massachusetts
| | - Erik Hansson
- La Isla Network, Washington, D.C.,School of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | | | - Zachary J Schlader
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
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Chapman CL, Johnson BD, Parker MD, Hostler D, Pryor RR, Schlader Z. Kidney physiology and pathophysiology during heat stress and the modification by exercise, dehydration, heat acclimation and aging. Temperature (Austin) 2020; 8:108-159. [PMID: 33997113 PMCID: PMC8098077 DOI: 10.1080/23328940.2020.1826841] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/17/2020] [Accepted: 09/17/2020] [Indexed: 02/06/2023] Open
Abstract
The kidneys' integrative responses to heat stress aid thermoregulation, cardiovascular control, and water and electrolyte regulation. Recent evidence suggests the kidneys are at increased risk of pathological events during heat stress, namely acute kidney injury (AKI), and that this risk is compounded by dehydration and exercise. This heat stress related AKI is believed to contribute to the epidemic of chronic kidney disease (CKD) occurring in occupational settings. It is estimated that AKI and CKD affect upwards of 45 million individuals in the global workforce. Water and electrolyte disturbances and AKI, both of which are representative of kidney-related pathology, are the two leading causes of hospitalizations during heat waves in older adults. Structural and physiological alterations in aging kidneys likely contribute to this increased risk. With this background, this comprehensive narrative review will provide the first aggregation of research into the integrative physiological response of the kidneys to heat stress. While the focus of this review is on the human kidneys, we will utilize both human and animal data to describe these responses to passive and exercise heat stress, and how they are altered with heat acclimation. Additionally, we will discuss recent studies that indicate an increased risk of AKI due to exercise in the heat. Lastly, we will introduce the emerging public health crisis of older adults during extreme heat events and how the aging kidneys may be more susceptible to injury during heat stress.
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Affiliation(s)
- Christopher L. Chapman
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, USA
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
| | - Blair D. Johnson
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, IN, USA
| | - Mark D. Parker
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
- Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - David Hostler
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, USA
| | - Riana R. Pryor
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, USA
| | - Zachary Schlader
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, IN, USA
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Acute Kidney Injury Biomarker Responses to Short-Term Heat Acclimation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17041325. [PMID: 32092895 PMCID: PMC7068478 DOI: 10.3390/ijerph17041325] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 02/15/2020] [Accepted: 02/17/2020] [Indexed: 12/12/2022]
Abstract
The combination of hyperthermia, dehydration, and strenuous exercise can result in severe reductions in kidney function, potentially leading to acute kidney injury (AKI). We sought to determine whether six days of heat acclimation (HA) mitigates the rise in clinical biomarkers of AKI during strenuous exercise in the heat. Twenty men completed two consecutive 2 h bouts of high-intensity exercise in either hot (n = 12, 40 °C, 40% relative humidity) or mild (n = 8, 24 °C, 21% relative humidity) environments before (PreHA) and after (PostHA) 4 days of 90–120 min of exercise per day in a hot or mild environment. Increased clinical biomarkers of AKI (CLINICAL) was defined as a serum creatinine increase ≥0.3 mg·dL−1 or estimated glomerular filtration rate (eGFR) reduction >25%. Creatinine similarly increased in the hot environment PreHA (0.35 ± 0.23 mg·dL−1) and PostHA (0.39 ± 0.20 mg·dL−1), with greater increases than the mild environment at both time points (0.11 ± 0.07 mg·dL−1, 0.08 ± 0.06 mg·dL−1, p ≤ 0.001), respectively. CLINICAL occurred in the hot environment PreHA (n = 9, 75%), with fewer participants with CLINICAL PostHA (n = 7, 58%, p = 0.007), and no participants in the mild environment with CLINICAL at either time point. Percent change in plasma volume was predictive of changes in serum creatinine PostHA and percent changes in eGFR both PreHA and PostHA. HA did not mitigate reductions in eGFR nor increases in serum creatinine during high-intensity exercise in the heat, although the number of participants with CLINICAL was reduced PostHA.
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