Sports Medicine

, Volume 31, Issue 1, pp 47–59 | Cite as

Alterations in Energy Metabolism During Exercise and Heat Stress

  • Mark A. FebbraioEmail author
Review Article


Much of the research that has examined the interaction between metabolism and exercise has been conducted in comfortable ambient conditions. It is clear, however, that environmental temperature, particularly extreme heat, is a major practical issue one must consider when examining muscle energy metabolism. When exercise is conducted in very high ambient temperatures, the gradient for heat dissipation is significantly reduced which results in changes to thermoregulatory mechanisms designed to promote body heat loss. This can ultimately impact upon hormonal and metabolic responses to exercise which act to alter substrate utilisation. In general, the literature examining metabolic responses to exercise and heat stress has demonstrated a shift towards increased carbohydrate use and decreased fat use. Although glucose production appears to be augmented during exercise in the heat, glucose disposal and utilisation appears to be unaltered. In contrast, glycogen use has been consistently demonstrated to be augmented during exercise in the heat. This increase in glycogenolysis is observed via both aerobic and anaerobic pathways. Although several hypotheses have been proposed as mechanisms for the substrate shift towards greater carbohydrate metabolism during exercise and heat stress, recent work suggests that an augmented sympatho-adrenal response and intramuscular temperature may be responsible for such a phenomenon.


Heat Stress Hepatic Glucose Production Muscle Blood Flow Lactate Accumulation Cool Environment 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. 1.
    Buskirk ER. Temperature regulation with exercise. Exerc Sport Sci Rev 1997; 5: 45–88Google Scholar
  2. 2.
    Gisolfi CV, Wenger CB. Temperature regulation during exercise: old concepts, new ideas. Exerc Sport Sci Rev 1984; 12: 339–72PubMedCrossRefGoogle Scholar
  3. 3.
    Nadel ER. Recent advances in temperature regulation during exercise in humans. Fed Proc 1985; 44 (7): 2286–92PubMedGoogle Scholar
  4. 4.
    Rowell LB. Human cardiovascular adjustments to exercise and thermal stress. Physiol Rev 1974; 54: 75–159PubMedGoogle Scholar
  5. 5.
    Sawka MN, Coyle EF. Influence of body water and blood volume on thermoregulation and exercise performance in the heat. Med Sci Sports Exerc 1999; 27: 167–218Google Scholar
  6. 6.
    Fink WJ, Costill DL, Van Handel PJ. Leg muscle metabolism during exercise in the heat and cold. Eur J Appl Physiol 1975; 34:183–90CrossRefGoogle Scholar
  7. 7.
    Febbraio MA, Snow RJ, Hargreaves M, et al. Muscle metabolism during exercise and heat stress in trained men: effect of acclimation. J Appl Physiol 1994; 76: 589–97PubMedGoogle Scholar
  8. 8.
    Febbraio MA, Snow RJ, Stathis CG, et al. Effect of heat stress on muscle energy metabolism during exercise. J Appl Physiol 1994; 77: 2827–31PubMedGoogle Scholar
  9. 9.
    Hargreaves M, Angus D, Howlett K, et al. Effect of heat stress on glucose kinetics during exercise. J Appl Physiol 1996; 81: 1594–97PubMedGoogle Scholar
  10. 10.
    King DS, Costill DL, Fink WJ, et al. Muscle metabolism during exercise in the heat in unacclimatized and acclimatized humans. J Appl Physiol 1985; 59 (5): 1350–4PubMedGoogle Scholar
  11. 11.
    Kirwan JP, Costill DL, Kuipers H, et al. Substrate utilization in leg muscle of men after heat acclimation. J Appl Physiol 1987; 63: 31–5PubMedGoogle Scholar
  12. 12.
    Young A.J, Sawka MN, Levine L, et al. Skeletal muscle metabolism during exercise is influenced by heat acclimation. J Appl Physiol 1985; 59: 1929–35PubMedGoogle Scholar
  13. 13.
    Gonzalez-Alonso J, Calbet JAL, Nielsen B. Metabolic and thermodynamic responses to dehydration-induced reductions in blood flow in exercising humans. J Physiol 1999; 520: 577–89PubMedCrossRefGoogle Scholar
  14. 14.
    Hargreaves M, Dillo P, Angus D, et al. Effect of fluid ingestion on muscle metabolism during prolonged exercise. J Appl Physiol 1996; 80: 363–6PubMedGoogle Scholar
  15. 15.
    Febbraio MA, Snow RJ, Stathis CG, et al. Blunting the rise in body temperature reduces muscle glycogenolysis during exercise in humans. Exp Physiol 1996; 81: 685–93PubMedGoogle Scholar
  16. 16.
    Parkin JM, Carey MF, Zhao S, et al. Effect of ambient temperature on human skeletal muscle metabolism during fatiguing submaximal exercise. J Appl Physiol 1999; 86: 902–8PubMedCrossRefGoogle Scholar
  17. 17.
    Kozlowski S, Brzezinska Z, Kruk B, et al. Exercise hyperthermia as a factor limiting physical performance: temperature effect on muscle metabolism. J Appl Physiol 1985: 59:766–73PubMedGoogle Scholar
  18. 18.
    Maxwell NS, Gardner F, Nimmo MA. Intermittent running: muscle metabolism in the heat and effect of hypohydration. Med Sci Sports Exerc 1999: 31: 675–83PubMedCrossRefGoogle Scholar
  19. 19.
    Nielsen B, Savard G, Richter EA, et al. Muscle blood flow and muscle metabolism during exercise and heat stress. J Appl Physiol 1990: 69: 1040–6PubMedGoogle Scholar
  20. 20.
    Yaspelkis III BB, Scroop GC, Wilmore KM, et al. Carbohydrate metabolism during exercise in hot and thermoneutral environments. Int J Sports Med 1993; 14: 13–9PubMedCrossRefGoogle Scholar
  21. 21.
    Young AJ, Sawka MN, Levine L, et al. Metabolic and thermal adaptations from endurance training in hot and cold water. J Appl Physiol 1995; 78: 793–801PubMedGoogle Scholar
  22. 22.
    Chesley A, Hultman E, Spriet LL. Effects of epinephrine infusion on muscle glycogenolysis during intense aerobic exercise. Am J Physiol 1995; 268 (1 Pt 1): E127–34PubMedGoogle Scholar
  23. 23.
    Hargreaves M, McConell G, Proietto J. Influence of muscle glycogen on glycogenolysis and glucose uptake during exercise in humans. J Appl Physiol 1995; 78: 288–92PubMedCrossRefGoogle Scholar
  24. 24.
    Hespel, P, Richter EA. Mechanisms linking glycogen and glycogenolytic rate in perfused contracting rat skeletal muscle. Biochem J 1992; 284: 777–80PubMedGoogle Scholar
  25. 25.
    Rowell LB, Brengelmann GL, Blackmon JR, et al. Splanchnic blood flow and metabolism in heat stressed man. J Appl Physiol 1968; 24: 475–84PubMedGoogle Scholar
  26. 26.
    Dolny DG, Lemon PWR. Effect of ambient temperature on protein breakdown during prolonged exercise. J Appl Physiol 1988; 64: 550–5PubMedGoogle Scholar
  27. 27.
    Wendling PS, Peters SJ, Heigenhauser GJF, et al. Variability of triacylglecerol content in human skeletal muscle biopsy samples. J Appl Physiol 1996; 81: 1150–5PubMedGoogle Scholar
  28. 28.
    Snow RJ, Febbraio MA, Carey ME, et al. Heat stress increases ammonia accumulation during exercise. Exp Physiol 1993; 78: 847–50PubMedGoogle Scholar
  29. 29.
    Graham TE, Rush JWE, MacLean DA. Skeletal muscle amino acid metabolism and ammonia production during exercise. In: Hargreaves M, editor. Exercise metabolism. Champaign (IL): Human Kinetics, 1995: 131–76Google Scholar
  30. 30.
    Febbraio MA, Murton P, Selig SE, Clark SA, Lambert DL, Angus DJ, Carey MF. Effect of CHO ingestion on exercise metabolism and performance in different ambient temperatures. Medicine and Science in Sports and Exercise 1996 28: 1380–7PubMedCrossRefGoogle Scholar
  31. 31.
    Kjær M. Hepatic fuel metabolism during exercise. In: Hargreaves M, editor. Exercise metabolism. Champaign (IL): Human Kinetics, 1995: 73–97Google Scholar
  32. 32.
    Jeukendrup AE, Wagenmakers AIM, Stegen JH, et al. Carbohydrate ingestion can completely suppress endogenous glucose production during exercise. Am J Physiol 1999; 276 (4 Pt 1): E672–83Google Scholar
  33. 33.
    McConell G, Fabris S, Proietto J, et al. Effects of carbohydrate ingestion on glucose kinetics during exercise. J Appl Physiol 1994; 77: 1537–41PubMedGoogle Scholar
  34. 34.
    Howlett K, Angus DJ, Proietto J, et al. Effect of increased blood glucose availability on glucose kinetics during exercise. J Appl Physiol 1998; 84: 1413–7PubMedGoogle Scholar
  35. 35.
    Angus DJ, Febbraio MA, Lasini D, et al. Effect of carbohydrate ingestion on glucose kinetics during exercise in the heat. J Appl Physiol. In pressGoogle Scholar
  36. 36.
    Sawka MN, Young AJ, Caderette BS, et al. Influence of heat stress and acclimation on maximal aerobic power. Eur J Appl Physiol 1984; 53: 294–8CrossRefGoogle Scholar
  37. 37.
    Rowell LB, Blackmon JR, Martin RH, et al. Hepatic clearance of indocyanine green in man under thermal and exercise stresses. J Appl Physiol 1965; 20: 384–94PubMedGoogle Scholar
  38. 38.
    Radigan LR, Robinson S. Effect of environmental heat stress and exercise on renal blood flow and filtration rate. J Appl Physiol 1949; 2: 185–91PubMedGoogle Scholar
  39. 39.
    Rowell LB. Human circulation: regulation during physical stress. New York: Oxford University Press, 1986Google Scholar
  40. 40.
    Rowell LB, O’Leary DS, Kellogg DL Jr. Integration of cardiovascular control systems in dynamic exercise. In: Rowell LB, Shepherd IT, editors. Handbook of physiology. Section 12. Exercise: regulation and integration of multiple systems. New York: Oxford University Press, 1996Google Scholar
  41. 41.
    Young AJ. Energy substrate utilization during exercise in extreme environments. Exerc Sports Sci Rev 1990; 18: 65–117CrossRefGoogle Scholar
  42. 42.
    Bell A, Hales J, King R, et al. Influence of heat stress on exercise-induced changes in regional blood flow in sheep. J Appl Physiol 1983; 55: 1916–23PubMedGoogle Scholar
  43. 43.
    Nielsen B, Hales JRS, Strange S, et al. Human circulatory and thermoregulatory adaptations with heat acclimation and exercise in a hot, dry environment. J Physiol 1993; 460: 467–85PubMedGoogle Scholar
  44. 44.
    Nielsen B, Strange S, Christensen NJ, et al. Acute and adaptive responses in humans to exercise in a warm, humid environment. Pflügers Arch 1997; 434 (1): 49–56PubMedCrossRefGoogle Scholar
  45. 45.
    Savard GK, Nielsen B, Laszczynska J, et al. Muscle blood flow is not reduced in humans during moderate exercise and heat stress. J Appl Physiol 1988; 64: 649–57PubMedGoogle Scholar
  46. 46.
    Smolander J, Louhevaara V. Effects of heat stress on muscle blood flow during dynamic handgrip exercise. Eur J Appl Physiol 1992; 65: 215–20CrossRefGoogle Scholar
  47. 47.
    Gonzalez-Alonso J, Calbet JAL, Nielsen B. Muscle blood flow is reduced with dehydration during prolonged exercise in humans. J Physiol 1999; 513: 895–905CrossRefGoogle Scholar
  48. 48.
    Gonzalez-Alonso J, Mora-Rodriguez R, Below PR, et al. Dehydration markedly impairs cardiovascular function in hyperthermic endurance athletes during exercise. J Appl Physiol 1997; 82: 1229–36PubMedGoogle Scholar
  49. 49.
    Schumacker PT, Rowland J, Saltz S, et al. Effects of hyperthermia and hypothermia on oxygen extraction by tissues during hypovolemia. J Appl Physiol 1987; 63: 1246–52PubMedGoogle Scholar
  50. 50.
    Clarke MG, Colqhoun EQ, Rattigan S, et al. Vascular and endocrine control of muscle metabolism. Am J Physiol 1995; 268:E797–812Google Scholar
  51. 51.
    Gollnick PD, Armstrong RB, Saubert CW 4th, et al. Glycogen depletion patterns in human skeletal muscle fibres during prolonged work. Pflügers Arch 1973; 344 (1): 1–12PubMedCrossRefGoogle Scholar
  52. 52.
    Saltin B, Hermansen L. Esophageal, rectal and muscle temperature during exercise. J Appl Physiol 1966; 21: 1757–62PubMedGoogle Scholar
  53. 53.
    Florkin M, Stoltz EH. Comprehensive biochemistry. 12. New York: Elselvier, 1968Google Scholar
  54. 54.
    Edwards RHT, Harris RC, Hultman E, et al. 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; 220: 335–52PubMedGoogle Scholar
  55. 55.
    Galbo H, Houston ME, Christensen NJ, et al. The effect of water temperature on the hormonal response to prolonged swimming. Acta Physiol Scand 1979; 105 (3): 326–37PubMedCrossRefGoogle Scholar
  56. 56.
    Powers SK, Howley ET, Cox R. Blood lactate concentrations during submaximal work under differing environmental conditions. J Sports Med Phys Fitness 1985; 25 (3): 84–9PubMedGoogle Scholar
  57. 57.
    Greenhaff PL, Ren J-M, Söderlund K, et al. Energy metabolism in single human muscle fibers during contractions with and without epinephrine infusion. Am J Physiol 1991; 260 (2 Pt 1): E713–8Google Scholar
  58. 58.
    Jansson E, Hjemdahl P, Kaijser L. Epinephrine induced changes in muscle carbohydrate metabolism during exercise in male subjects. J Appl Physiol 1986; 60: 1466–70PubMedGoogle Scholar
  59. 59.
    Spriet LL, Ren J-M, Hultman E. Epinephrine infusion enhances muscle glycogenolysis during prolonged electrical stimulation. J Appl Physiol 1988; 64: 1439–44PubMedGoogle Scholar
  60. 60.
    Febbraio MA, Carey MF, Snow RJ, et al. Influence of elevated muscle temperature on metabolism during intense, dynamic exercise. Am J Physiol 1996; 271: R1251–5Google Scholar
  61. 61.
    Starkie RL, Hargreaves M, Lambert DL, et al. Effect of temperature on muscle metabolism during submaximal exercise. Exp Physiol 1999; 84: 775–84PubMedCrossRefGoogle Scholar
  62. 62.
    Uyeda K. Phosphofructokinase. Adv Enzymol Relat Areas Mol Biol 1979; 48: 193–244PubMedGoogle Scholar
  63. 63.
    Ren J-M, Hultman E. Regulation of phosphorylase a activity in human skeletal muscle. J Appl Physiol 1990; 67: 919–23Google Scholar
  64. 64.
    Galbo H. Hormonal and metabolic adaptations to exercise. New York: Thiemme-Stratton Inc., 1983Google Scholar
  65. 65.
    Richter EA, Ruderman NB, Gavras H, et al. Muscle glycogenolysis during exercise: dual control by epinephrine and contractions. Am J Physiol 1982; 242 (1): E25–32Google Scholar
  66. 66.
    Richter EA, Sonne B, Christensen NJ, et al. Role of epinephrine for muscular glycogenolysis and pancreatic hormone secretion in running rats. Am J Physiol 1981; 240 (5): E526–32Google Scholar
  67. 67.
    Issekutz, B. Effect of epinephrine on carbohydrate metabolism in exercising dogs. Metabolism 1985; 34: 457–64PubMedCrossRefGoogle Scholar
  68. 68.
    Hashimoto I, Knudson MB, Noble EG, et al. Exercise-induced glycogenolysis in sympathectomized rats. Jpn J Physiol 1982; 32: 153–60PubMedCrossRefGoogle Scholar
  69. 69.
    Issekutz B. Effect of β-adrenergic blockade on lactate turnover in exercising dogs. J Appl Physiol 1984; 57: 1754–59PubMedGoogle Scholar
  70. 70.
    Wendling PS, Peters SJ, Heigenhauser GJF, et al. Epinephrine infusion does not enhance net muscle glycogenolysis during prolonged aerobic exercise. Can J Appl Physiol 1996; 21: 271–84PubMedCrossRefGoogle Scholar
  71. 71.
    Febbraio MA, Lambert DL, Starkie RL, et al. Effect of epinephrine on muscle glycogenolysis during exercise in trained men. J Appl Physiol 1998; 84: 465–70PubMedGoogle Scholar
  72. 72.
    Turner MJ, Howley ET, Tanaka H, et al. Effect of graded epinephrine infusion on blood lactate response to exercise. J Appl Physiol 1995; 79: 1206–11PubMedGoogle Scholar
  73. 73.
    Putman CT, Spriet LL, Hultman E, et al. Pyruvate dehydrogenase activity and acetyl group accumulation during exercise after different diets. Am J Physiol 1993; 265 (5 Pt 1): E752–60Google Scholar
  74. 74.
    Martin WH III. Effects of acute and chronic exercise on fat metabolism. Exerc Sports Sci Rev 1996; 24: 203–31CrossRefGoogle Scholar
  75. 75.
    Cooper DM, Wasserman DW, Vranic M, et al. Glucose turnover in response to exercise during high- and low FIO2 breathing in man. Am J Physiol 1986; 251: E209–14Google Scholar
  76. 76.
    Kjær M, Kiens B, Hargreaves M, et al. Influence of active muscle mass on glucose homeostasis during exercise in humans. J Appl Physiol 1991; 71: 552–7PubMedGoogle Scholar
  77. 77.
    Sonne B, Mikines KJ, Richter EA, et al. Role of liver nerves and adrenal medulla in glucose turnover in running rats. J Appl Physiol 1985; 59: 1640–6PubMedGoogle Scholar
  78. 78.
    Kjær M, Engfred K, Fernandes A, et al. Regulation of hepatic glucose production during exercise in humans: role of sympathoadrenergic activity. Am J Physiol 1993; 265 (2 Pt 1): E275–83Google Scholar
  79. 79.
    Kjær M, Keiding S, Engfred K, et al. Glucose homeostasis during exercise in humans with a liver or kidney transplant. Aim J Physiol 1995; 268 (4 Pt 1): E636–44Google Scholar
  80. 80.
    Howlett K, Febbraio MA, Hargreaves M. Liver glucose production during strenuous exercise in humans: role of epinephrine. Am J Physiol 1999; 276 (6 Pt 1): E1130–5Google Scholar
  81. 81.
    Howlett K, Galbo H, Lorentsen J, et al. Effect of adrenaline on glucose kinetics during exercise in adrenalectomised humans. J Physiol 1999; 519: 911–21PubMedCrossRefGoogle Scholar

Copyright information

© Adis International Limited 2001

Authors and Affiliations

  1. 1.Exercise Physiology & Metabolism Laboratory, Department of PhysiologyUniversity of MelbourneParkvilleAustralia

Personalised recommendations