Sports Medicine

, Volume 25, Issue 4, pp 221–240 | Cite as

Effects of Thermal Stress During Rest and Exercise in the Paediatric Population

  • Bareket Falk
Review Article


Thermoregulation during exposure to hot or cold environments differs between children and adults. Many physical and physiological changes occur during growth and maturation that can affect thermoregulation during rest as well as during exercise. Thus, physical as well as physiological differences between children and adults may explain the different response to thermal stress.

The main physical difference between children and adults affecting thermoregulation is the much higher surface—area-to-mass ratio of children. In a warm environment this allows them to rely more on dry heat loss and less on evaporative cooling. However, in extreme conditions, hot or cold, the greater surface—areato- mass ratio results in a higher rate of heat absorption or heat loss, respectively. The lower body fat in girls compared with women provides lower insulation and presents a disadvantage in a cold environment. The smaller blood volume in children compared with adults, even relative to body size, may limit the potential for heat transfer during heat exposure and may compromise exercise performance in the heat.

The main physiological difference between children and adults is in the sweating mechanism, affecting their thermoregulation in the heat, but not in the cold. The lower sweating rate characteristic of children is due to a lower sweating rate per gland and not to a lower number of sweat glands. In fact, children are characterised by a higher density of heat-activated sweat glands. The lower sweating rate per gland may be explained by the smaller sweat gland size, a lower sensitivity of the sweating mechanism to thermal stimuli and, possibly, a lower sweat gland metabolic capacity.

Other physiological differences between children and adults that may affect thermoregulation include metabolic, circulatory and hormonal disparities. The higher metabolic cost of locomotion in children provides an added strain on the thermoregulatory system during exercise in the heat. On the other hand, during acute exposure to cold it may prove advantageous by increasing heat production. Circulatory differences, such as a lower cardiac output at any given exercise intensity and the lower haemoglobin concentration in boys compared with men, are likely to increase the cardiovascular strain during exercise in the heat, although their effects in a cold environment are unknown. Finally, testosterone and prolactin are 2 hormones that differ in baseline levels between children and adults and may affect sweat gland function and sweat composition. These possible effects need to be further investigated.

The effectiveness of thermoregulation is reflected by the stability of core temperature. In a thermoneutral environment, children are characterised by a similar rectal temperature and a higher skin temperature when compared with adults. The latter may reflect the higher reliance on dry heat loss compared with evaporative cooling in children. In a hot environment, children’s body temperatures are higher compared with adults while walking and running but not necessarily while cycling. This may be related to the higher metabolic cost, and therefore higher heat production, in children while walking or running but not while cycling. In a cold environment, children are characterised by lower skin temperatures, reflecting greater vasoconstriction. Their metabolic heat is increased in the cold to a greater extent than that of adults, although this appears to be sufficient to maintain their body temperature during exercise but not during prolonged rest.

Neither children nor adults sufficiently replace fluid loss during exercise in the heat. Nevertheless, recent studies suggest that in children, when the available beverage is flavoured and enriched with NaCl and carbohydrates, dehydration can be prevented. The hypohydration, which frequently accompanies exercise in the heat, and the resultant added cardiovascular strain, may be more detrimental in children than in adults, because children rely more on dry heat loss, and therefore on elevated skin blood flow, to dissipate body heat.

Based on a few studies, it appears that acclimation to heat is similar in children and adults. The main difference is the slower rate of heat acclimation in children. No studies are available on cold acclimatisation or acclimation in children or adolescents.

Physical training results in enhanced thermoregulation during heat stress in children as in adults. Limited data suggest that training may improve thermoregulation during cold exposure in children. However, the effects of training on the thermoregulatory response to cold stress in children and adolescents need to be studied further.


Adis International Limited Cold Stress Sweat Gland Cold Exposure Eccrine Sweat Gland 
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  1. 1.
    Davies CTM. Thermal responses to exercise in children. Ergon 1981; 24: 55–61CrossRefGoogle Scholar
  2. 2.
    Delmarche P, Bittel J, Lacour JR, et al. Thermoregulation at rest and during exercise in prepubertal boys. Eur J Appl Physiol 1990; 60: 436–40CrossRefGoogle Scholar
  3. 3.
    Gullestad R. Temperature regulation in children during exercise. Acta Paediatr Scand 1975; 64: 257–63PubMedCrossRefGoogle Scholar
  4. 4.
    Tochihara Y, Ohnaka T, Nagai Y. Thermal responses of 6- to 8-year old children during immersion of their legs in a hot water bath. Appl Hum Sci 1995; 14: 23–8Google Scholar
  5. 5.
    Forbes GB. Body composition in adolescence. In: Falkner F, Tanner JM, editors. Human growth: Vol. 2. 2nd ed. New York: Plenum Press, 1986: 119–45Google Scholar
  6. 6.
    Visser HKA. Some physiological and clinical aspects of puberty. Arch Dis Child 1973; 48: 169–82PubMedCrossRefGoogle Scholar
  7. 7.
    Astrand PO. Experimental studies of physical work capacity in relation to sex and age. Copenhagen: Munksgaard, 1952Google Scholar
  8. 8.
    Drinkwater BL, Kupprat IC, Denton JE, et al. Response of prepubertal girls and college women to work in the heat. J Appl Physiol 1977; 43: 1046–53PubMedGoogle Scholar
  9. 9.
    Falk B, Bar-Or O, MacDougall JD. The thermoregulatory response of pre-, mid- and late-pubertal boys to exercise in dry heat. Med Sci Sports Exerc 1992; 24: 688–94PubMedGoogle Scholar
  10. 10.
    Orenstein DM, Henke KG, Costill DL, et al. Exercise and heat stress in cystic fibrosis patients. Ped Res 1983; 17: 267–9CrossRefGoogle Scholar
  11. 11.
    Bar-Or O. Pediatric sports medicine for the practitioner. New York: Springer Verlag, 1983: 259–99Google Scholar
  12. 12.
    Smolander J, Bar-Or O, Korhonen O. et al. Thermoregulation during rest and exercise in the cold in pre- and early pubescent boys and in young men. J Appl Physiol 1992; 72: 1589–94PubMedCrossRefGoogle Scholar
  13. 13.
    Bar-Or O, Shephard RJ, Allen CL. Cardiac output of 10- to 13-year-old boys and girls during submaximal exercise. J Appl Physiol 1971; 30: 219–23PubMedGoogle Scholar
  14. 14.
    Krabbe S, Christensen T, Worm J, et al. Relationship between haemoglobin and serum testosterone in normal children and adolescents and in boys with delayed puberty. Acta Paediatr Scand 1978; 67: 655–8PubMedCrossRefGoogle Scholar
  15. 15.
    Kawahata A. Sex differences in sweating. In: Yoshimura et al., editors. Essential problems in climatic physiology. Kyoto: Nankodo, 1960Google Scholar
  16. 16.
    Brisson GR, Audet A, Ledoux M, et al. Exercise-induced blood prolactin variations in trained adult males: a thermic stress more than an osmotic stress. Hormone Res 1986; 23: 200–6PubMedCrossRefGoogle Scholar
  17. 17.
    Soldin SJ, Hicks JM. Pediatric reference ranges. Washington, DC: AACC Press, 1995Google Scholar
  18. 18.
    Rees J, Shuster S. Pubertal induction of sweat gland activity. Clin Sci 1981; 60: 689–92PubMedGoogle Scholar
  19. 19.
    Kaufman FL, Mills DE, Hughson RL, et al. Effects of bromocriptine on sweat gland function during heat acclimatization. Horm Res 1988; 29: 31–8PubMedCrossRefGoogle Scholar
  20. 20.
    Robertson MT, Boyajian MJ, Patterson K, et al. Modulation of the chloride concentration of human sweat by prolactin. Endocrinology 1986; 119: 2439–44PubMedCrossRefGoogle Scholar
  21. 21.
    Falk B, Bar-Or O, MacDougall JD. Aldosterone and prolactin response to exercise in the heat among circum-pubertal boys. J Appl Physiol 1991; 71: 1741–5PubMedGoogle Scholar
  22. 22.
    Bar-Or O. Climate and the exercising child: a review. Int J Sports Med 1980; 1: 53–65CrossRefGoogle Scholar
  23. 23.
    Bar-Or O. Temperature regulation during exercise in children and adolescents. In: Gisolfi CV, Lamb DR, editors. Perspectives in exercise science and sports medicine. Vol. 2: Youth, exercise and sport. Indianapolis: Benchmark Press, 1989: 335–62Google Scholar
  24. 24.
    Sato K, Leidal R, Sato, F. Morphology and development of an apoeccrine sweat gland in human axillae. Am J Physiol 1987; 252: R166–80PubMedGoogle Scholar
  25. 25.
    Landing BH, Wells TR, Wiliamson ML. Studies on growth of eccrine sweat glands. In: Cheek DB, editor. Human growth: body composition, cell growth, energy and intelligence. Philadelphia: Lea & Febriger, 1968: 382–94Google Scholar
  26. 26.
    Wolfe S, Cage G, Epstein M, et al. Metabolic studies on isolated human eccrine sweat glands. J Clin Invest 1970; 49: 1880–4PubMedCrossRefGoogle Scholar
  27. 27.
    Sato K, Sato F. Individual variations in structure and function of human eccrine sweat glands. Am J Physiol 1983; 245: R203–8PubMedGoogle Scholar
  28. 28.
    Kuno Y. Human perspiration. Springfield (IL): Charles C. Thomas, 1956Google Scholar
  29. 29.
    Bar-Or O, Lundegren HM, Buskirk ER. Distribution of heatactivated sweat glands in obese and lean men and women. J Appl Physiol 1969; 26: 403–9PubMedGoogle Scholar
  30. 30.
    Szabo G. The number of eccrine sweat glands in human skin. Adv Biol Skin 1962; 3: 1–5Google Scholar
  31. 31.
    Falk B, Bar-Or O, MacDougall JD, et al. Sweat gland response to exercise in the heat among pre-, mid- and late-pubertal boys. Med Sci Sports Exerc 1992; 24: 313–9PubMedGoogle Scholar
  32. 32.
    Collins KJ, Sargent F, Weiner JS. Excitation and depression of eccrine sweat glands by acetylcholine, acetyl-β-methylcholine and adrenaline. J Physiol 1959; 148: 592–614PubMedGoogle Scholar
  33. 33.
    Wada M. Sudorific action of adrenalin on the human sweat glands and determination of their excitability. Science 1950; 111: 376–7PubMedCrossRefGoogle Scholar
  34. 34.
    Araki T, Toda Y, Matsushita K, et al. Age differences in sweating during muscular exercise. Jpn J Fitness Sports Med 1979; 28: 239–48Google Scholar
  35. 35.
    Inbar O. Acclimatization to dry and hot environment in young adults and children 8-10 years old [dissertation]. Columbia University, 1978Google Scholar
  36. 36.
    Tsuzuki-Hayakawa K, Tochihara Y, Ohnaka T. Thermoregulation during heat exposure of young children compared to their mothers. Eur J Appl Physiol 1995; 72: 12–7CrossRefGoogle Scholar
  37. 37.
    Wagner JA, Robinson S, Tzankoff SW, et al. Heat tolerance and acclimatization to work in the heat in relation to age. J Appl Physiol 1972; 33: 616–22PubMedGoogle Scholar
  38. 38.
    Falk B, Bar-Or O, MacDougal JD, et al. Sweat lactate in exercising children and adolescents of varying physical maturity. J Appl Physiol 1991; 71: 1735–40PubMedGoogle Scholar
  39. 39.
    Eriksson BO, Saltin B. Muscle metabolism during exercise in boys aged 11 to 16 years compared to adults. Acta Paediatr Belg 1974; 28 Suppl.: 257–65PubMedGoogle Scholar
  40. 40.
    Falk B, Bar-Or O. Longitudinal changes in peak aerobic and anaerobic mechanical power of circumpubertal boys. Pediatr Exerc Med 1993; 5: 318–31Google Scholar
  41. 41.
    Falk B. Physiological and health aspects of exercise in hot and cold climates. In: Bar-Or O, editor. Encylopaedia of sports medicine: the child and the adolescent athlete. Oxford: Blackwell Scientific, 1996: 326–52Google Scholar
  42. 42.
    Bittel J, Henane R. Comparison of neutral exchanges in men and women under neutral and hot conditions. J Physiol (Lond) 1975; 250: 475–489Google Scholar
  43. 43.
    Haymes EM, McCormick RJ, Buskirk ER. Heat tolerance of exercise lean and obese prepubertal boys. J Appl Physiol 1975; 39: 457–61PubMedGoogle Scholar
  44. 44.
    McCormick RJ, Buskirk ER. Heat tolerance of exercising lean and obese middle-aged men [abstract]. Fed Proc 1974; 33: 441Google Scholar
  45. 45.
    Jokinen E, Valimaki I, Antila K, et al. Children in sauna: cardiovascular adjustment. Pediatrics 1990; 86: 282–8PubMedGoogle Scholar
  46. 46.
    Leppaluoto J. Human thermoregulation in sauna. Ann Clin Res 1988; 20: 240–3PubMedGoogle Scholar
  47. 47.
    Sohar E, Shapira Y. The physiological reactions of women and children marching during heat. Proc Isr Physiol Pharmacol Soc 1965; 1: 50Google Scholar
  48. 48.
    Haymes EM, Buskirk ER, Hodgson JL, et al. Heat tolerance of exercising lean and heavy prepubertal girls. J Appl Physiol 1974; 36: 566–71PubMedGoogle Scholar
  49. 49.
    Rowland TW, Staab JS, Unnithan VB, et al. Mechanical efficiency during cycling in prepubertal and adult males. Int J Sports Med 1990; 11: 452–5PubMedCrossRefGoogle Scholar
  50. 50.
    Sloan RE, Keatinge WR. Cooling rates of young people swimming in cold water. J Appl Physiol 1973; 35: 371PubMedGoogle Scholar
  51. 51.
    Inoue Y, Araki T, Tsujta J. The thermoregulatory responses of prepubertal boys and young men in changing temperature linearly from 28 to 15°C. Eur J Appl Physiol 1996; 72: 204–8CrossRefGoogle Scholar
  52. 52.
    Araki T, Tsujita J, Matsushita K, et al. Thermoregulatory responses of prepubertal boys to heat and cold in relation to physical training. J Hum Ergol (Tokyo) 1980; 9: 69–80Google Scholar
  53. 53.
    Wagner JA, Robinson S, Marino RP. Age and temperature regulation of humans in neutral and cold environments. J Appl Physiol 1974; 37: 562–5PubMedGoogle Scholar
  54. 54.
    Falk B, Bar-Eli M, Dotan R, et al. Physiological and cognitive responses to cold exposure in 11-12 year-old boys. Am J Hum Biol 1997; 9: 39–49CrossRefGoogle Scholar
  55. 55.
    Mackova J, Sturmova M, Macek M. Prolonged exercise in prepubertal boys in warm and cold environments. In: Illmarinen, J, Valimaki I, editors. Children and sports. Heidelberg: Springer Verlag, 1984: 135–41CrossRefGoogle Scholar
  56. 56.
    Young A. Human adaptation to cold. In: Pandolf KB, Sawka MN, Gonzalez RR, editors. Human performance physiology and environmental medicine at terrestrial extremes. Indianapolis: Benchmark Press, 1988: 401–34Google Scholar
  57. 57.
    Carlson JS, Le Rossignol P. Children and adults exercising in hot wet climatic conditions with different levels of radiant heat [abstract]. North American Society of Pediatric Exercise Medicine, Ninth Annual Meeting; 1994 Aug 11-14; PittsburghGoogle Scholar
  58. 58.
    Marsh ML, Mahon AD, Naftzger LA. Children’s physiological responses to exercise in a cold and neutral temperature. Proceedings of the North American Society of Pediatric Exercise Medicine Meeting: 1992 Oct 30-Nov 1; MiamiGoogle Scholar
  59. 59.
    Ueda T, Choi Th, Kurokawa T. Ratings of perceived exertion in a group of children while swimming at different temperatures. Ann Physiol Anthropol 1994; 13: 23–31PubMedCrossRefGoogle Scholar
  60. 60.
    Mackie JM. Physiological responses of twin children to exercise under conditions of heat stress [MSc. thesis]. University of Waterloo, 1982Google Scholar
  61. 61.
    Jokinen E, Valimaki I. Children in sauna: electrocardiographic abnormalities. Acta Paediatr Scand 1991; 80: 370–4PubMedCrossRefGoogle Scholar
  62. 62.
    Jokinen E, Valimaki I, Marniemi J, et al. Children in sauna: hormonal adjustments to intensive short thermal stress. Acta Physiol Scand 1991; 80: 370–4CrossRefGoogle Scholar
  63. 63.
    Meyer F, Bar-Or O, MacDougall D, et al. Sweat electrolyte loss during exercise in the heat: effects of gender and maturation. Med Sci Sports Exerc 1992; 24: 776–81PubMedGoogle Scholar
  64. 64.
    Foster KG, Hey EN, Katz G. The response of the sweat glands of the new-born baby to thermal stimuli and intradermal acetylcholine. J Physiol 1969; 203: 13–29PubMedGoogle Scholar
  65. 65.
    Falk B, Bar-Or O, MacDougall JD, et al. A longitudinal analysis of the sweating response of pre-, mid- and late-pubertal boys during exercise in the heat. Am J Hum Biol 1992; 4: 527–35CrossRefGoogle Scholar
  66. 66.
    Shapiro Y, Pandolf KB, BA Arellini, et al. Physiological responses of men and women to humid and dry heat. J Appl Physiol 1980; 49: 1–8PubMedGoogle Scholar
  67. 67.
    Main K, Nilsson KO, Skiakkebaek NE. Influence of sex and growth hormone deficiency on sweating. Scand J Clin Lab Invest 1991; 51: 475–80PubMedCrossRefGoogle Scholar
  68. 68.
    Meyer F, Bar-Or O. Fluid and electrolyte loss during exercise: the pediatric angle. Sports Med 1994; 18: 4–9PubMedCrossRefGoogle Scholar
  69. 69.
    Shwachman H, Mahmoodian A. The sweat test and cystic fibrosis. Diagn Med 1982; Jun: 61–77Google Scholar
  70. 70.
    Meyer F, Bar-Or O, Wilk B. Children’s perceptual responses to ingesting drinks of different compositions during and following exercise in the heat. Int J Sport Nutr 1995; 5: 13–24PubMedGoogle Scholar
  71. 71.
    Sens DA, Simmons MA, Spicer SS. The analysis of human sweat proteins by isoelectric focusing. I: Sweat collection utilizing the macroduct system demonstrates the presence of previously unrecognized sex-related proteins. Ped Res 1985; 19: 873–8CrossRefGoogle Scholar
  72. 72.
    Bar-Or O, Dotan R, Inbar O, et al. Voluntary hypohydration in 10- to 12-year-old boys. J Appl Physiol 1980; 48: 104–8PubMedGoogle Scholar
  73. 73.
    Bar-Or O, Blimkie CJR, Hay JA, et al. Voluntary dehydration and heat intolerance in cystic fibrosis. Lancet 1992; 339: 696–9PubMedCrossRefGoogle Scholar
  74. 74.
    Pugh LGC, Crobett JL, Johnson RH. Rectal temperatures, weight losses and sweat rates in marathon running. J Appl Physiol 1967; 23: 347–52PubMedGoogle Scholar
  75. 75.
    Wilk B, Bar-Or O. Effect of drink flavor and NaCl on voluntary drinking and hydration in boys exercising in the heat. J Appl Physiol 1996; 80: 1112–7PubMedCrossRefGoogle Scholar
  76. 76.
    Fortney SM, Wenger CG, Bove JR, et al. Effect of hyperosmolality on control of blood flow and sweating. J Appl Physiol 1984; 57: 1688–95PubMedGoogle Scholar
  77. 77.
    Kenney WL, Tankersley CG, Newswanger DL, et al. Age and hypohydration independently influence the peripheral response to heat stress. J Appl Physiol 1990; 68: 1902–8PubMedCrossRefGoogle Scholar
  78. 78.
    Sawka MN, Young AJ, Francesconi RB, et al. Thermoregulation and blood responses during exercise at graded hypohydration levels. J Appl Physiol 1985; 59: 1394PubMedGoogle Scholar
  79. 79.
    Meyer F, Bar-Or O, Salsberg A, et al. Hypohydration during exercise in children: effect on thirst, drink preferences, and rehydration. Int J Sports Nutr 1994; 4: 22–35Google Scholar
  80. 80.
    Meyer F, Bar-Or O, MacDougall JD, et al. Drink composition and the electrolyte balance of children exercising in the heat. Med Sci Sports Exerc 1995; 27: 882–7PubMedGoogle Scholar
  81. 81.
    Bar-Or O, Wilk B. Water and electrolyte replenishment in the exercising child. Int J Sport Nutr 1996; 6: 93–9PubMedGoogle Scholar
  82. 82.
    Bar-Or O, Inbar, O. Relationship between perceptual and physiological changes during heat acclimatization in 8- to 10-year-old boys. In: Lavalee H, Shephard RJ, editors. Frontiers of activity and child health. Québec: Pelican, 1977: 205–14Google Scholar
  83. 83.
    Armstrong LE, Maresh CM. The induction and decay of heat acclimatization in trained athletes. Sports Med 1991; 12: 302–12PubMedCrossRefGoogle Scholar
  84. 84.
    Inbar O, Bar-Or O, Dotan R, et al. Conditioning vs exercise in heat as methods for acclimatizing 8-10 year old boys to dry heat. J Appl Physiol 1981; 50: 406–11PubMedGoogle Scholar
  85. 85.
    Docherty D, Eckerson JD, Hayward JS. Physique and thermoregulation in prepubertal males during exercise in a warm, humid environment. Am J Phys Anthropol 1986; 70: 19–23PubMedCrossRefGoogle Scholar
  86. 86.
    Matsushita K, Araki T. The effect of physical training on thermoregulatory responses of preadolescent boys to heat and cold. Jpn J Phys Fitness 1980; 29: 69–74Google Scholar

Copyright information

© Adis International Limited 1998

Authors and Affiliations

  • Bareket Falk
    • 1
  1. 1.Department of Physiology, Ribstein Center for Research and Sport Medicine SciencesWingate InstituteNetanyaIsrael

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