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. 1999 Jul-Sep;34(3):246–252.

Exercise in the Heat. I. Fundamentals of Thermal Physiology, Performance Implications, and Dehydration

Douglas J Casa 1
PMCID: PMC1322918  PMID: 16558572

Abstract

Objective:

To present the critical issue of exercise in the heat in a format that provides physiologic foundations (Part I) and then applies the established literature to substantial, usable guidelines that athletic trainers can implement on a daily basis when working with athletes who exercise in the heat (Part II).

Data Sources:

The databases MEDLINE and SPORT Discus were searched from 1980 to 1999, with the terms “hydration,” “heat,” “dehydration,” “cardiovascular,” “thermoregulatory,” “physiology,” and “exercise,” among others. The remaining citations are knowledge base.

Data Synthesis:

Part I introduces athletic trainers to some of the basic physiologic and performance responses to exercise in the heat.

Conclusions/Recommendations:

The medical supervision of athletes who exercise in hot environments requires an in-depth understanding of basic physiologic responses and performance considerations. Part I of this article aims to lay the scientific foundation for efficient implementation of the guidelines for monitoring athletic performance in the heat provided in Part II.

Keywords: cardiovascular, heat stress, thermoregulatory

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Armstrong L. E., Costill D. L., Fink W. J. Influence of diuretic-induced dehydration on competitive running performance. Med Sci Sports Exerc. 1985 Aug;17(4):456–461. doi: 10.1249/00005768-198508000-00009. [DOI] [PubMed] [Google Scholar]
  2. Armstrong L. E., Epstein Y. Fluid-electrolyte balance during labor and exercise: concepts and misconceptions. Int J Sport Nutr. 1999 Mar;9(1):1–12. doi: 10.1123/ijsn.9.1.1. [DOI] [PubMed] [Google Scholar]
  3. Armstrong L. E., Maresh C. M., Gabaree C. V., Hoffman J. R., Kavouras S. A., Kenefick R. W., Castellani J. W., Ahlquist L. E. Thermal and circulatory responses during exercise: effects of hypohydration, dehydration, and water intake. J Appl Physiol (1985) 1997 Jun;82(6):2028–2035. doi: 10.1152/jappl.1997.82.6.2028. [DOI] [PubMed] [Google Scholar]
  4. BUSKIRK E. R., IAMPIETRO P. F., BASS D. E. Work performance after dehydration: effects of physical conditioning and heat acclimatization. J Appl Physiol. 1958 Mar;12(2):189–194. doi: 10.1152/jappl.1958.12.2.189. [DOI] [PubMed] [Google Scholar]
  5. Bergh U., Ekblom B. Physical performance and peak aerobic power at different body temperatures. J Appl Physiol Respir Environ Exerc Physiol. 1979 May;46(5):885–889. doi: 10.1152/jappl.1979.46.5.885. [DOI] [PubMed] [Google Scholar]
  6. Bijlani R. L., Sharma K. N. Effect of dehydration and a few regimes of rehydration on human performance. Indian J Physiol Pharmacol. 1980 Oct-Dec;24(4):255–266. [PubMed] [Google Scholar]
  7. Bosco J. S., Greenleaf J. E., Bernauer E. M., Card D. H. Effects of acute dehydration and starvation on muscular strength and endurance. Acta Physiol Pol. 1974 Sep-Oct;25(5):411–421. [PubMed] [Google Scholar]
  8. Bosco J. S., Terjung R. L., Greenleaf J. E. Effects of progressive hypohydration on maximal isometric muscular strength. J Sports Med Phys Fitness. 1968 Jun;8(2):81–86. [PubMed] [Google Scholar]
  9. Burge C. M., Carey M. F., Payne W. R. Rowing performance, fluid balance, and metabolic function following dehydration and rehydration. Med Sci Sports Exerc. 1993 Dec;25(12):1358–1364. [PubMed] [Google Scholar]
  10. Cadarette B. S., Sawka M. N., Toner M. M., Pandolf K. B. Aerobic fitness and the hypohydration response to exercise-heat stress. Aviat Space Environ Med. 1984 Jun;55(6):507–512. [PubMed] [Google Scholar]
  11. Caldwell J. E., Ahonen E., Nousiainen U. Differential effects of sauna-, diuretic-, and exercise-induced hypohydration. J Appl Physiol Respir Environ Exerc Physiol. 1984 Oct;57(4):1018–1023. doi: 10.1152/jappl.1984.57.4.1018. [DOI] [PubMed] [Google Scholar]
  12. Candas V., Libert J. P., Brandenberger G., Sagot J. C., Amoros C., Kahn J. M. Hydration during exercise. Effects on thermal and cardiovascular adjustments. Eur J Appl Physiol Occup Physiol. 1986;55(2):113–122. doi: 10.1007/BF00714992. [DOI] [PubMed] [Google Scholar]
  13. Convertino V. A., Armstrong L. E., Coyle E. F., Mack G. W., Sawka M. N., Senay L. C., Jr, Sherman W. M. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc. 1996 Jan;28(1):i–vii. doi: 10.1097/00005768-199610000-00045. [DOI] [PubMed] [Google Scholar]
  14. Costill D. L., Coté R., Fink W. Muscle water and electrolytes following varied levels of dehydration in man. J Appl Physiol. 1976 Jan;40(1):6–11. doi: 10.1152/jappl.1976.40.1.6. [DOI] [PubMed] [Google Scholar]
  15. Craig E. N., Cummings E. G. Dehydration and muscular work. J Appl Physiol. 1966 Mar;21(2):670–674. doi: 10.1152/jappl.1966.21.2.670. [DOI] [PubMed] [Google Scholar]
  16. Durkot M. J., Martinez O., Brooks-McQuade D., Francesconi R. Simultaneous determination of fluid shifts during thermal stress in a small-animal model. J Appl Physiol (1985) 1986 Sep;61(3):1031–1034. doi: 10.1152/jappl.1986.61.3.1031. [DOI] [PubMed] [Google Scholar]
  17. Edwards R. H., Harris R. C., Hultman E., Kaijser L., Koh D., Nordesjö L. O. Effect of temperature on muscle energy metabolism and endurance during successive isometric contractions, sustained to fatigue, of the quadriceps muscle in man. J Physiol. 1972 Jan;220(2):335–352. doi: 10.1113/jphysiol.1972.sp009710. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Fortney S. M., Nadel E. R., Wenger C. B., Bove J. R. Effect of blood volume on sweating rate and body fluids in exercising humans. J Appl Physiol Respir Environ Exerc Physiol. 1981 Dec;51(6):1594–1600. doi: 10.1152/jappl.1981.51.6.1594. [DOI] [PubMed] [Google Scholar]
  19. Fortney S. M., Vroman N. B., Beckett W. S., Permutt S., LaFrance N. D. Effect of exercise hemoconcentration and hyperosmolality on exercise responses. J Appl Physiol (1985) 1988 Aug;65(2):519–524. doi: 10.1152/jappl.1988.65.2.519. [DOI] [PubMed] [Google Scholar]
  20. González-Alonso J., Mora-Rodríguez R., Below P. R., Coyle E. F. Dehydration reduces cardiac output and increases systemic and cutaneous vascular resistance during exercise. J Appl Physiol (1985) 1995 Nov;79(5):1487–1496. doi: 10.1152/jappl.1995.79.5.1487. [DOI] [PubMed] [Google Scholar]
  21. Greenleaf J. E. Problem: thirst, drinking behavior, and involuntary dehydration. Med Sci Sports Exerc. 1992 Jun;24(6):645–656. [PubMed] [Google Scholar]
  22. HENRY J. P., GAUER O. H. The influence of temperature upon venous pressure in the foot. J Clin Invest. 1950 Jul;29(7):855–861. doi: 10.1172/JCI102318. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Harrison M. H., Edwards R. J., Fennessy P. A. Intravascular volume and tonicity as factors in the regulation of body temperature. J Appl Physiol Respir Environ Exerc Physiol. 1978 Jan;44(1):69–75. doi: 10.1152/jappl.1978.44.1.69. [DOI] [PubMed] [Google Scholar]
  24. Horswill C. A. Applied physiology of amateur wrestling. Sports Med. 1992 Aug;14(2):114–143. doi: 10.2165/00007256-199214020-00004. [DOI] [PubMed] [Google Scholar]
  25. Horswill C. A. Weight loss and weight cycling in amateur wrestlers: implications for performance and resting metabolic rate. Int J Sport Nutr. 1993 Sep;3(3):245–260. doi: 10.1123/ijsn.3.3.245. [DOI] [PubMed] [Google Scholar]
  26. Irion G. L. Responses of distance runners and sprinters to exercise in a hot environment. Aviat Space Environ Med. 1987 Oct;58(10):948–953. [PubMed] [Google Scholar]
  27. Kenney W. L., Johnson J. M. Control of skin blood flow during exercise. Med Sci Sports Exerc. 1992 Mar;24(3):303–312. [PubMed] [Google Scholar]
  28. Mack G., Nose H., Nadel E. R. Role of cardiopulmonary baroreflexes during dynamic exercise. J Appl Physiol (1985) 1988 Oct;65(4):1827–1832. doi: 10.1152/jappl.1988.65.4.1827. [DOI] [PubMed] [Google Scholar]
  29. Murray R. Dehydration, hyperthermia, and athletes: science and practice. J Athl Train. 1996 Jul;31(3):248–252. [PMC free article] [PubMed] [Google Scholar]
  30. Murray R. Fluid needs in hot and cold environments. Int J Sport Nutr. 1995 Jun;5 (Suppl):S62–S73. doi: 10.1123/ijsn.5.s1.s62. [DOI] [PubMed] [Google Scholar]
  31. Nadel E. R., Cafarelli E., Roberts M. F., Wenger C. B. Circulatory regulation during exercise in different ambient temperatures. J Appl Physiol Respir Environ Exerc Physiol. 1979 Mar;46(3):430–437. doi: 10.1152/jappl.1979.46.3.430. [DOI] [PubMed] [Google Scholar]
  32. Nadel E. R. Circulatory and thermal regulations during exercise. Fed Proc. 1980 Apr;39(5):1491–1497. [PubMed] [Google Scholar]
  33. Nadel E. R. Control of sweating rate while exercising in the heat. Med Sci Sports. 1979 Spring;11(1):31–35. [PubMed] [Google Scholar]
  34. Nadel E. R., Fortney S. M., Wenger C. B. Effect of hydration state of circulatory and thermal regulations. J Appl Physiol Respir Environ Exerc Physiol. 1980 Oct;49(4):715–721. doi: 10.1152/jappl.1980.49.4.715. [DOI] [PubMed] [Google Scholar]
  35. Nielsen B., Hansen G., Jorgensen S. O., Nielsen E. Thermoregulation in exercising man during dehydration and hyperhydration with water and saline. Int J Biometeorol. 1971 Dec;15(2):195–200. doi: 10.1007/BF01803897. [DOI] [PubMed] [Google Scholar]
  36. Nose H., Mack G. W., Shi X. R., Nadel E. R. Shift in body fluid compartments after dehydration in humans. J Appl Physiol (1985) 1988 Jul;65(1):318–324. doi: 10.1152/jappl.1988.65.1.318. [DOI] [PubMed] [Google Scholar]
  37. Nose H., Morimoto T., Ogura K. Distribution of water losses among fluid compartments of tissues under thermal dehydration in the rat. Jpn J Physiol. 1983;33(6):1019–1029. doi: 10.2170/jjphysiol.33.1019. [DOI] [PubMed] [Google Scholar]
  38. Pandolf K. B. Aging and human heat tolerance. Exp Aging Res. 1997 Jan-Mar;23(1):69–105. doi: 10.1080/03610739708254027. [DOI] [PubMed] [Google Scholar]
  39. Pichan G., Gauttam R. K., Tomar O. S., Bajaj A. C. Effect of primary hypohydration on physical work capacity. Int J Biometeorol. 1988 Sep;32(3):176–180. doi: 10.1007/BF01045276. [DOI] [PubMed] [Google Scholar]
  40. Roberts M. F., Wenger C. B., Stolwijk J. A., Nadel E. R. Skin blood flow and sweating changes following exercise training and heat acclimation. J Appl Physiol Respir Environ Exerc Physiol. 1977 Jul;43(1):133–137. doi: 10.1152/jappl.1977.43.1.133. [DOI] [PubMed] [Google Scholar]
  41. Rowell L. B., Blackmon J. R., Martin R. H., Mazzarella J. A., Bruce R. A. Hepatic clearance of indocyanine green in man under thermal and exercise stresses. J Appl Physiol. 1965 May;20(3):384–394. doi: 10.1152/jappl.1965.20.3.384. [DOI] [PubMed] [Google Scholar]
  42. Rowell L. B., Brengelmann G. L., Blackmon J. R., Twiss R. D., Kusumi F. Splanchnic blood flow and metabolism in heat-stressed man. J Appl Physiol. 1968 Apr;24(4):475–484. doi: 10.1152/jappl.1968.24.4.475. [DOI] [PubMed] [Google Scholar]
  43. Rowell L. B., Marx H. J., Bruce R. A., Conn R. D., Kusumi F. Reductions in cardiac output, central blood volume, and stroke volume with thermal stress in normal men during exercise. J Clin Invest. 1966 Nov;45(11):1801–1816. doi: 10.1172/JCI105484. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. SALTIN B. CIRCULATORY RESPONSE TO SUBMAXIMAL AND MAXIMAL EXERCISE AFTER THERMAL DEHYDRATION. J Appl Physiol. 1964 Nov;19:1125–1132. doi: 10.1152/jappl.1964.19.6.1125. [DOI] [PubMed] [Google Scholar]
  45. Sawka M. N., Gonzalez R. R., Young A. J., Dennis R. C., Valeri C. R., Pandolf K. B. Control of thermoregulatory sweating during exercise in the heat. Am J Physiol. 1989 Aug;257(2 Pt 2):R311–R316. doi: 10.1152/ajpregu.1989.257.2.R311. [DOI] [PubMed] [Google Scholar]
  46. Sawka M. N., Hubbard R. W., Francesconi R. P., Horstman D. H. Effects of acute plasma volume expansion on altering exercise-heat performance. Eur J Appl Physiol Occup Physiol. 1983;51(3):303–312. doi: 10.1007/BF00429066. [DOI] [PubMed] [Google Scholar]
  47. Sawka M. N. Physiological consequences of hypohydration: exercise performance and thermoregulation. Med Sci Sports Exerc. 1992 Jun;24(6):657–670. [PubMed] [Google Scholar]
  48. Sawka M. N., Young A. J., Cadarette B. S., Levine L., Pandolf K. B. Influence of heat stress and acclimation on maximal aerobic power. Eur J Appl Physiol Occup Physiol. 1985;53(4):294–298. doi: 10.1007/BF00422841. [DOI] [PubMed] [Google Scholar]
  49. Sawka M. N., Young A. J., Francesconi R. P., Muza S. R., Pandolf K. B. Thermoregulatory and blood responses during exercise at graded hypohydration levels. J Appl Physiol (1985) 1985 Nov;59(5):1394–1401. doi: 10.1152/jappl.1985.59.5.1394. [DOI] [PubMed] [Google Scholar]
  50. Sawka M. N., Young A. J., Latzka W. A., Neufer P. D., Quigley M. D., Pandolf K. B. Human tolerance to heat strain during exercise: influence of hydration. J Appl Physiol (1985) 1992 Jul;73(1):368–375. doi: 10.1152/jappl.1992.73.1.368. [DOI] [PubMed] [Google Scholar]
  51. Senay L. C., Jr Effects of exercise in the heat on body fluid distribution. Med Sci Sports. 1979 Spring;11(1):42–48. [PubMed] [Google Scholar]
  52. Senay L. C., Jr Temperature regulation and hypohydration: a singular view. J Appl Physiol Respir Environ Exerc Physiol. 1979 Jul;47(1):1–7. doi: 10.1152/jappl.1979.47.1.1. [DOI] [PubMed] [Google Scholar]
  53. Silva N. L., Boulant J. A. Effects of osmotic pressure, glucose, and temperature on neurons in preoptic tissue slices. Am J Physiol. 1984 Aug;247(2 Pt 2):R335–R345. doi: 10.1152/ajpregu.1984.247.2.R335. [DOI] [PubMed] [Google Scholar]
  54. Sproles C. B., Smith D. P., Byrd R. J., Allen E. Circulatory responses to submaximal exercise after dehydration and rehydration. J Sports Med Phys Fitness. 1976 Jun;16(2):98–105. [PubMed] [Google Scholar]
  55. Torranin C., Smith D. P., Byrd R. J. The effect of acute thermal dehydration and rapid rehydration on isometric and istonic endurance. J Sports Med Phys Fitness. 1979 Mar;19(1):1–9. [PubMed] [Google Scholar]
  56. Walsh R. M., Noakes T. D., Hawley J. A., Dennis S. C. Impaired high-intensity cycling performance time at low levels of dehydration. Int J Sports Med. 1994 Oct;15(7):392–398. doi: 10.1055/s-2007-1021076. [DOI] [PubMed] [Google Scholar]
  57. Webster S., Rutt R., Weltman A. Physiological effects of a weight loss regimen practiced by college wrestlers. Med Sci Sports Exerc. 1990 Apr;22(2):229–234. [PubMed] [Google Scholar]
  58. Young A. J. Energy substrate utilization during exercise in extreme environments. Exerc Sport Sci Rev. 1990;18:65–117. [PubMed] [Google Scholar]

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