Human Physiology in the Heat

  • Luke N. Belval
  • Ollie Jay
Part of the SpringerBriefs in Medical Earth Sciences book series (BRIEFSMEEASC)


Safety and performance during exercise and physical activity in the heat are limited by the human body’s physiological ability to balance heat gain and heat loss. Circumstances where heat gain from internal or external sources outweighs the ability to dissipate it can lead to dangerous increases in body temperature. Humans possess an ability to adapt to exercise in warm environments and minimize the deleterious effects through heat acclimatization. In situations where human physiology cannot overcome thermal challenges, exertional heat illnesses can manifest. These exertional heat illnesses can range from relatively benign to potentially fatal when left untreated. Technologies, techniques, and strategies to mitigate the consequences of exercise in warm environments should consider the existing physiological mechanisms to successfully promote health and maximize performance.


Heat balance Uncompensable heat stress Compensable heat stress Exertional heat illness Heat acclimatization 


  1. 1.
    Lieberman DE (2015) Human locomotion and heat loss: an evolutionary perspective. Compr Physiol 5:99–117Google Scholar
  2. 2.
    Whipp BJ, Wasserman K (1969) Efficiency of muscular work. J Appl Physiol 26:644–648CrossRefGoogle Scholar
  3. 3.
    Snellen JW (1960) External work in level and grade walking on a motor-driven treadmill. J Appl Physiol 15:759–753CrossRefGoogle Scholar
  4. 4.
    Pihlainen K, Santtila M, Häkkinen K, Lindholm H, Kyröläinen H (2014) Cardiorespiratory responses induced by various military field tasks. Mil Med 179:218–224CrossRefGoogle Scholar
  5. 5.
    Tam E, Rossi H, Moia C, Berardelli C, Rosa G, Capelli C, Ferretti G (2012) Energetics of running in top-level marathon runners from Kenya. Eur J Appl Physiol 112:3797–3806CrossRefGoogle Scholar
  6. 6.
    Parsons K (1993) Human thermal environments. CRC Boca Raton, FLGoogle Scholar
  7. 7.
    Mitchell, D. (1974). Convective heat loss from man and other animals. Heat Loss from Animals and Man. J. L. Monteith and L. E. Mount. London, Elsevier.Google Scholar
  8. 8.
    ISO (1989) ISO 7933 - Hot environments: analytical determination and interpretation of thermal stress using calculation of required sweat rate. ISO, GenevaGoogle Scholar
  9. 9.
    Wenger CB (1972) Heat of evaporation of sweat: thermodynamic considerations. J Appl Physiol 32:456–459CrossRefGoogle Scholar
  10. 10.
    Cramer MN, Jay O (2014) Selecting the correct exercise intensity for unbiased comparisons of thermoregulatory responses between groups of different mass and surface area. J Appl Physiol 116:1123–1132CrossRefGoogle Scholar
  11. 11.
    Dervis S, Coombs GB, Chaseling GK, Filingeri D, Smoljanić J, Jay O (2016) A comparison of thermoregulatory responses to exercise between mass-matched groups with large differences in body fat. J Appl Physiol 120:615–623CrossRefGoogle Scholar
  12. 12.
    Deren TM, Coris EE, Bain AR, Walz SM, Jay O (2012) Sweating is greater in NCAA football linemen independently of heat production. Med Sci Sports Exerc 44:244–252CrossRefGoogle Scholar
  13. 13.
    Lorenzo S, Halliwill JR, Sawka MN, Minson CT (2010) Heat acclimation improves exercise performance. J Appl Physiol 109:1140–1147CrossRefGoogle Scholar
  14. 14.
    Racinais S, Alonso JM, Coutts AJ et al (2015) Consensus recommendations on training and competing in the heat. - PubMed - NCBI. Scand J Med Sci Sports 25:6–19CrossRefGoogle Scholar
  15. 15.
    Armstrong LE (1992) Artificial heat acclimatization. Natl Strength Cond Assoc J 14:72–73CrossRefGoogle Scholar
  16. 16.
    Coyle EF, González-Alonso J (2001) Cardiovascular drift during prolonged exercise: new perspectives. Exerc Sport Sci Rev 29:88–92Google Scholar
  17. 17.
    Périard JD, Travers GJS, Racinais S, Sawka MN (2016) Cardiovascular adaptations supporting human exercise-heat acclimation. Auton Neurosci 196:52–62CrossRefGoogle Scholar
  18. 18.
    Armstrong LE, Maresh CM (1991) The induction and decay of heat acclimatisation in trained athletes. Sports Med 12:302–312CrossRefGoogle Scholar
  19. 19.
    Poirier MP, Gagnon D, Friesen BJ, Hardcastle SG, Kenny GP (2015) Whole-body heat exchange during heat acclimation and its decay. Med Sci Sports Exerc 47:390–400CrossRefGoogle Scholar
  20. 20.
    Garrett AT, Creasy R, Rehrer NJ, Patterson MJ, Cotter JD (2011) Effectiveness of short-term heat acclimation for highly trained athletes. Eur J Appl Physiol 112:1827–1837CrossRefGoogle Scholar
  21. 21.
    Casadio JR, Kilding AE, Cotter JD, Laursen PB (2016) From lab to real world: heat acclimation considerations for elite athletes. Sports Med 23:531Google Scholar
  22. 22.
    Buono MJ, Numan TR, Claros RM, Brodine SK, Kolkhorst FW (2009) Is active sweating during heat acclimation required for improvements in peripheral sweat gland function? Am J Physiol Regul Integr Comp Physiol 297:R1082–R1085CrossRefGoogle Scholar
  23. 23.
    Casa DJ, Csillan D (2009) Preseason heat-acclimatization guidelines for secondary school athletics. J Athl Train 44:332CrossRefGoogle Scholar
  24. 24.
    Armstrong LE (2003) Exertional heat illnesses. Human Kinetics, Champaign, ILGoogle Scholar
  25. 25.
    Miller KC (2015) Rethinking the cause of exercise-associated muscle cramping: moving beyond dehydration and electrolyte losses. Curr Sports Med Rep 14:353–354CrossRefGoogle Scholar
  26. 26.
    Bergeron MF (2007) Exertional heat cramps: recovery and return to play. J Sport Rehabil 16:190–196CrossRefGoogle Scholar
  27. 27.
    Casa DJ, Demartini JK, Bergeron MF et al (2015) National Athletic Trainers' association position statement: Exertional heat illnesses. J Athl Train 50:986–1000CrossRefGoogle Scholar
  28. 28.
    Armstrong LE, Lopez RM (2010) Return to exercise training after heat exhaustion. J Sport Rehabil 16:182–189CrossRefGoogle Scholar
  29. 29.
    Leon LR, Bouchama A (2015) Heat stroke. Compr Physiol 5:611–647CrossRefGoogle Scholar
  30. 30.
    Epstein Y, Roberts WO (2011) The pathophysiology of heat stroke: an integrative view of the final common pathway. Scand J Med Sci Sports 21:742–748CrossRefGoogle Scholar
  31. 31.
    Selkirk GA, McLellan TM, Wright HE, Rhind SG (2008) Expression of intracellular cytokines, HSP72, and apoptosis in monocyte subsets during exertional heat stress in trained and untrained individuals. Am J Physiol Regul Integr Comp Physiol 296:R575–R586CrossRefGoogle Scholar
  32. 32.
    Kazman JB, Purvis DL, Heled Y, Lisman P, Atias D, Van Arsdale S, Deuster PA (2015) Women and exertional heat illness: identification of gender specific risk factors. US Army Med Dep J,p 58–66Google Scholar
  33. 33.
    Hosokawa Y, Casa DJ, Rosenberg H et al (2017) Round table on malignant hyperthermia in physically active populations: meeting proceedings. J Athl Train 52:377–383CrossRefGoogle Scholar
  34. 34.
    O'Connor FG, Casa DJ, Bergeron MF et al (2010) American College of Sports Medicine roundtable on exertional heat stroke--return to duty/return to play: conference proceedings. Curr Sports Med Rep 9:314–321CrossRefGoogle Scholar
  35. 35.
    Armstrong LE, Casa DJ, Millard-Stafford ML, Moran DS, Pyne SW, Roberts WO (2007) Exertional heat illness during training and competition. Med Sci Sports Exerc 39:556–572CrossRefGoogle Scholar
  36. 36.
    Ganio MS, Brown CM, Casa DJ, Becker SM, Yeargin SW, McDermott BP, Boots LM, Boyd PW, Armstrong LE, Maresh CM (2009) Validity and reliability of devices that assess body temperature during indoor exercise in the heat. J Athl Train 44:124–135CrossRefGoogle Scholar
  37. 37.
    Casa DJ, Becker SM, Ganio MS et al (2007) Validity of devices that assess body temperature during outdoor exercise in the heat. J Athl Train 42:333–135Google Scholar
  38. 38.
    Huggins R, Glaviano N, Negishi N, Casa DJ, Hertel J (2012) Comparison of rectal and aural Core body temperature thermometry in Hyperthermic, exercising individuals: a meta-analysis. J Athl Train 47:329–338CrossRefGoogle Scholar
  39. 39.
    Mazerolle SM, Ganio MS, Casa DJ, Vingren J, Klau JF (2011) Is oral temperature an accurate measurement of deep body temperature? A systematic review. J Athl Train 46:566–573CrossRefGoogle Scholar
  40. 40.
    Casa DJ, Armstrong LE, Kenny GP, O'Connor FG, Huggins RA (2012) Exertional heat stroke: new concepts regarding cause and care. Curr Sports Med Rep 11:115–123CrossRefGoogle Scholar
  41. 41.
    Adams WM, Hosokawa Y, Casa DJ (2015) The timing of Exertional heat stroke survival starts prior to collapse. Curr Sports Med Rep 14:273–274CrossRefGoogle Scholar
  42. 42.
    Casa DJ, McDermott BP, Lee EC, Yeargin SW, Armstrong LE, Maresh CM (2007) Cold water immersion: the gold standard for exertional heatstroke treatment. Exerc Sport Sci Rev 35:141–149CrossRefGoogle Scholar
  43. 43.
    Demartini JK, Casa DJ, Stearns R, Belval L, Crago A, Davis R, Jardine J (2015) Effectiveness of cold water immersion in the treatment of exertional heat stroke at the Falmouth road race. Med Sci Sports Exerc 47:240–245CrossRefGoogle Scholar
  44. 44.
    Hosokawa Y, Adams WM, Belval LN, Vandermark LW, Casa DJ (2017) Tarp-assisted cooling as a method of whole-body cooling in Hyperthermic individuals. Ann Emerg Med 69:347–352CrossRefGoogle Scholar
  45. 45.
    Luhring KE, Butts CL, Smith CR, Bonacci JA, Ylanan RC, Ganio MS, McDermott BP (2016) Cooling effectiveness of a modified cold-water immersion method after exercise-induced hyperthermia. J Athl Train 51:946–951CrossRefGoogle Scholar
  46. 46.
    Sinclair WH, Rudzki SJ, Leicht AS, Fogarty AL, Winter SK, Patterson MJ (2009) Efficacy of field treatments to reduce body core temperature in hyperthermic subjects. Med Sci Sports Exerc 41:1984–1990CrossRefGoogle Scholar

Copyright information

© The Author(s) 2018

Authors and Affiliations

  1. 1.Korey Stringer Institute, Department of KinesiologyUniversity of ConnecticutStorrsUSA
  2. 2.University of SydneyLidcombeAustralia

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