Physiology of Exercise in the Cold
- Dr Thomas J. Doubt
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Recreational and job requirements have increased the incidence in which humans exercise in cold environments. Understanding the physiological responses while exposed to cold entails knowledge of how exercise and cold interact on metabolic, cardiopulmonary, muscle and thermal aspects of human performance. Where possible, distinctions are made between responses in cold air and cold water.
While there is no consensus for diets most appropriate for working cold exposures, the evidence is strong that adequate amounts of carbohydrate are necessary. Carbohydrate loading appears to be efficacious, as it is for other athletic endeavours.
Contrary to conventional wisdom, the combination of exercise and cold exposure does not act synergistically to enhance metabolism of fats. Free fatty acid (FFA) levels are not higher, and may be lower, with exercise in cold air or water when compared to corresponding warmer conditions. Glycerol, a good indicator of lipid mobilisation, is likewise reduced in the cold, suggesting impaired mobilisation from adipose tissue.
Catecholamines, which promote lipolysis, are higher during exercise in cold air and water, indicating that the reduced lipid metabolism is not due to a lack of adequate hormonal stimulation. It is proposed that cold-induced vasoconstriction of peripheral adipose tissue may account, in part, for the decrease in lipid mobilisation. The respiratory exchange ratio (RER) is often similar for exercise conducted in warm and cold climates, suggesting FFA utilisation is equivalent between warm and cold exposures. The fractional portion of oxygen consumption (V̇O2) used for FFA combustion may decrease slightly during exercise in the cold. This decrease may be related to a relative decrease in oxygen delivery (i.e. muscle blood flow) or to impaired lipid mobilisation.
Venous glucose is not substantially altered during exercise in the cold, but lactate levels are generally higher than with work in milder conditions. The time lag between production of lactate within the muscle and its release into the venous circulation may be increased by cold exposure.
Minute ventilation is substantially increased upon initial exposure to cold, and a relative hyperventilation may persist throughout exercise. With prolonged exercise, though, ventilation may return to values comparable to exercise in warmer conditions. Exercise V̇O2 is generally higher in the cold, but the difference between warm and cold environments becomes less as workload increases. Increases in oxygen uptake may be due to persistence of shivering during exercise, to an increase in muscle tonus in the absence of overshivering, or to nonshivering thermogenesis.
Heart rate is often, but not always, lower during exercise in the cold. The linear relationship between heart rate and oxygen consumption is displaced such that at a given rate oxygen uptake is higher. Cardiac arrhythmias are more frequent in the cold. Stroke volume tends to be higher than under warmer control conditions, but may decline sooner or at a rate equivalent to warm controls at heavy workloads. Cardiac output is similar to the same work done in temperature environments.
Cold-induced vasoconstriction occurs both in cutaneous and resting skeletal muscle beds, but inactive muscle provides most of the passive body insulation. With exercise insulation provided by muscle decreases as blood flow increases. Relative to warmer conditions, muscle blood flow at a given workload may be reduced if deep muscle temperature is below normal (i.e. 39°C optimum).
Respiratory heat loss is often assumed to represent 8% of the total metabolic heat production. However, during exercise this value will increase as minute ventilation increases. Loss of significant amounts of heat from the distal extremities can limit performance, even though the area is not directly involved with exercise.
Cooled muscle has a decreased capacity to generate force expressed on cross-sectional area. As a consequence, it may be necessary to recruit more fast twitch motor units. Glycolysis is higher in cooled muscle, which may account for higher lactate levels and greater rates of muscle glycogen depletion. Brief intense exercise will not raise cooled muscle temperature to normal limits, but mild exercise can maintain normal temperatures if exercise begins before the muscles become cooled.
Regional heat flux increases with exercise in the cold in direct proportion to the workload. Differing rates of heat loss can occur between active and inactive limbs, and individual rates are not constant throughout steady-state exercise. Peak rates of heat flux for inactive limbs occur during exercise, but peak flux for active limbs occurs in the postexercise period. At equal metabolic rates, more heat is lost with arm than with leg exercise.
Most of the heat generated by exercising muscle is transferred convectively to the core via the venous circulation. The amount of heat lost conductively to the environment through tissue depends upon factors such as subcutaneous fat. Thus, individuals with higher levels of fat (e.g. skinfold thickness) generally are better able to maintain their core temperature in cold environments.
Steady-state exercise V̇O2 values of approximately 2.0 L/min have been shown to prevent falls in core temperature in water as low as 15°C. Warmer temperatures are required in order to maintain core homeostasis during intermittent exercise.
Predicting an individual’s response to exercise in the cold is quite difficult because of the interplay of many factors. Using existing data, responses to some forms of exercise and environmental stress can be estimated with reasonable accuracy. However, the number of these type responses is small compared to the total number of possible permutations, showing that much is yet to be learned.
- Askew EW. Nutrition for a cold environment Physician and Sportsmedicine 17: 77–89, 1989.
- Blomstrand E, Essen-Gustavsson B. Influence of reduced muscle temperature on metabolism in type I and II human muscle fibres during intensive exercise. Acta Physiologica Scandinavica 131: 569–574, 1987. CrossRef
- Blomstrand E, Kaijser L, Martinsson A, Bergh U, Ekblom B. Temperature-induced changes in metabolic and hormonal responses to intensive dynamic exercise. Acta Physiologica Scandinavica 127: 477–484, 1986. CrossRef
- Cooper KE, Martin S, Riben P. Respiratory and other responses in subjects immersed in cold water. Journal of Applied Physiology 40: 903–910, 1976.
- Craig AB, Dvorak M. Thermal regulation of man exercising during water immersion. Journal of Applied Physiology 25: 28–35, 1968.
- Dolny DG, Lemon PWR. Effect of ambient temperature on protein breakdown during prolonged exercise. Journal of Applied Physiology 64: 550–555, 1988.
- Doubt TJ, Francis TJR. Hazards of cold water. In Torg et al. (Eds) Current therapy in sports medicine, pp. 150–155, BC Decker Inc., Philadelphia, 1989
- Doubt TJ, Hsieh S. Additive effects of caffeine and cold water during submaximal leg exercise. Medicine and Science in Sports and Exercise 23(4): 435–442, 1991.
- Doubt TJ, Mayers DM, Flynn ET. Transient cardiac sinus dysrhythmia occurring after cold water immersion. American Journal of Cardiology 59: 1421–1422, 1987. CrossRef
- Doubt TJ, Smith DJ. Lack of diurnal effects on periodic exercise during prolonged cold water immersion. Undersea Biomedical Research 17(2): 149–157, 1990.
- Dressendorfer RH, Morlock JF, Baker DG, Hong SK. Effects of head-out water immersion on cardiorespiratory responses to maximal cycling exercise. Undersea Biomedical Research 3: 177–187, 1976.
- Eldridge L. Sudden unexplained death syndrome in cold wafer scuba diving. Undersea Biomedical Research 6(Suppl.): 41, 1979.
- Ferretti G, Veicsteinas A, Rennie DW. Regional heat flows of resting and exercising men immersed in cool water. Journal of Applied Physiology 64: 1239–1248, 1988.
- Flavahan NA, Lindblad LE, Verbeuren TJ, Shepherd JT, Vanhoutte PM. Cooling and alpha1- and alpha2-adrenergic responses in cutaneous veins: role of receptor reserve. American Journal of Physiology 249: H950–H955, 1985.
- Gale EAM, Bennett M, Green JH, MacDonald LA. Hypoglycemia, hypothermia, and shivering in man. Clinical Sciences (London) 61: 463–469, 1981.
- Golden FC, Tipton MJ. Human thermal responses during leg-only exercise in cold water. Journal of Physiology (London) 391: 399–405, 1987.
- Goodman C, Rogers GG, Vermaak H, Goodman MR. Biochemical responses during recovery from maximal and submaximal swimming exercise. European Journal of Applied Physiology 54: 436–441, 1985. CrossRef
- Graham TE. Thermal, metabolic, and cardiovascular changes in men and women during cold stress. Medicine and Science in Sports and Exercise 20(Suppl.): S185–S192, 1988.
- Hayward MG, Keatinge WR. Roles of subcutaneous fat and thermoregulatory reflexes in determining ability to stabilize body temperature in water. Journal of Physiology (London) 320: 229–251, 1981.
- Hjemdahl P, Sollevi A. Vascular and metabolic responses to adrenergic stimulation in isolated canine subcutaneous adipose tissue at normal and reduced temperature. Journal of Physiology (London) 281: 325–338, 1978.
- Hoar PF, Raymond LW, Langworthy HC, Johsonbaugh RE, Sode J. Physiological responses of men working in 25.5°C water, breathing air or helium tri-mix. Journal of Applied Physiology 40: 606–610, 1976.
- Jacobs I, Romet T, Frim J, Hynes A. Effects of endurance fitness on responses to cold water immersion. Aviation, Space and Environmental Medicine 55: 715–720, 1984.
- Jacobs I, Romet TT, Kerrigan-Brown D. Muscle glycogen depletion during exercise at 9°C and 21°C. European Journal of Applied Physiology 54: 35–39, 1985. CrossRef
- Johnson JJ, Brengelmann GL, Hales JRS, Vanhoutte PM, Wenger CB. Regulation of the cutaneous circulation. Federation Proceedings 45: 2841–2850, 1986.
- Jones RJ, Lahiri A, Cashman PMM, Dore C, Raftery EB. Left ventricular function during isometric handgrip and cold stress in normal subjects. British Heart Journal 55: 246–252, 1986. CrossRef
- Keatinge WR. Cold immersion and swimming. Journal of the Royal Naval Medical Service 58: 171–176, 1972.
- Mager M, Francesconi R. The relationship of glucose metabolism to hypothermia. In Pozos RS & Wittmers LE (Eds) The nature and treatment of hypothermia, pp. 100–120, University of Minnesota Press, Minneapolis, 1983.
- McArdle WD, Magel JR, Lesmes GR, Pechar GS. Metabolic and cardiovascular adjustment to work in air and water at 18, 25, and 33°C. Journal of Applied Physiology 40: 85–90, 1976.
- McArdle WD, Magel JR, Spina RJ, Gergley TJ, Toner MM. Thermal adjustment to cold water exposure in exercising men and women. Journal of Applied Physiology 56: 1572–1577, 1984. CrossRef
- McGilvery RW. Biochemistry: a functional approach. WE Saunders Company, Philadelphia, PA, 1970
- McMurray RG, Horvath SM. Thermoregulation in swimmers and runners. Journal of Applied Physiology 46: 1086–1092, 1979.
- Mekjavic IB, Bligh J. The increased oxygen uptake upon immersion: the raised external pressure could be a causative factor. European Journal of Applied Physiology 58: 556–562, 1989. CrossRef
- Moore TO, Bernauer EM, Seto G, Park YS, Hong SK, et al. Effect of immersion at different water temperatures on graded exercise performance in man. Aerospace Medicine 41: 1404–1408, 1970.
- Nadel ER. Energy exchanges in water. Undersea Biomedical Research 11: 149–158, 1984.
- Newstead CG. The relationship between ventilation and oxygen consumption in man is the same during both moderate exercise and shivering. Journal of Physiology (London) 383: 455–459, 1987.
- Nunneley SA. Heat stress in protective clothing. Scandinavian Journal of Work, Environment, and Health 15(Suppl.): 52–57, 1989.
- Okada M. The cardiac rhythm in accidental hypothermia. Journal of Electrocardiology 17: 123–128, 1984. CrossRef
- Olschewski H, Bruck K. Thermoregulatory, cardiovascular, and muscular factors related to exercise after precooling. Journal of Applied Physiology 64: 803–811, 1988.
- Park YS, Pendergast DR, Rennie DW. Decrease in body insulation with exercise in cool water. Undersea Biomedical Research 11: 159–168, 1984.
- Pendergast DR. The effect of body cooling on oxygen transport during exercise. Medicine and Science in Sports and Exercise 20(Suppl.): S171–S176, 1988.
- Petrofsky JS, Burse RL, Lind AR. The effect of deep muscle temperature on the cardiovascular responses of man to static effort. European Journal of Applied Physiology 47: 7–16, 1981. CrossRef
- Pirnay F, Deroanne R, Petit JM. Influence of water temperature on thermal, circulatory and respiratory responses to muscular work. European Journal of Applied Physiology 37: 129–136, 1977. CrossRef
- Pozos R. Frequency analysis of shiver in humans and its alteration by the temperature of inspired air. In Keuhn (Ed.) Thermal constraints in diving, pp. 55–80, Undersea Medical Society, Bethesda, 1981.
- Rapp GM. Convection coefficients of man in a forensic area of thermal physiology: heat transfer in underwater exercise. Journal de Physiologie 63: 392–396, 1970.
- Raven PB, Wilkerson JE, Horvath SM, Bolduan NW. Thermal, metabolic, and cardiovascular responses to various degrees of cold stress. Canadian Journal of Physiological Pharmacology 53: 293–298, 1975. CrossRef
- Rennie DW. Tissue heat transfer in water: lessons from the Korean divers. Medicine and Science in Sports and Exercise 20(Suppl.): S177–S184, 1988.
- Rennie DW, DiPrampero P, Cerretelli PC. Effects of water immersion on cardiac output, heart rate, and stroke volume of man at rest and during exercise. Medicina dello Sport 24: 223–228, 1971.
- Rusch NJ, Shepherd JT, Vanhoutte PM. The effect of profound cooling on adrenergic neurotransmission in canine cutaneous veins. Journal of Physiology (London) 311: 57–65, 1981.
- Sagawa S, Shiraki K, Yousef MK, Konda N. Water temperature and intensity of exercise in maintenance of thermal equilibrium. Journal of Applied Physiology 65: 2413–2419, 1988.
- Sheldahl LM, Wann LS, Clifford PS, Tristani FE, Wolf LG, et al. Effect of central hypervolemia on cardiac performance during exercise. Journal of Applied Physiology 57: 1662–1667, 1984.
- Sherman WM, Costill DL, Fink WJ, Miller JM. Effect of exercisediet manipulation on muscle glycogen and its subsequent utilization during performance. International Journal of Sports Medicine 2: 114–118, 1981. CrossRef
- Sink KR, Thomas TR, Araujo J, Hill SF. Fat energy use and plasma lipid changes associated with exercise intensity and temperature. European Journal of Applied Physiology 58: 508–513, 1989. CrossRef
- Smith DJ, Deuster PA, Ryan CJ, Doubt TJ. Prolonged whole body immersion in cold water: hormonal and metabolic changes. Undersea Biomedical Research 17(2): 139–147, 1990.
- Stainsby WN, Brooks GA. Control of lactic acid metabolism in contracting muscles during exercise. Exercise and Sports Sciences Review 18: 29–64, 1990.
- Stevens GHJ, Graham TE, Wilson BA. Gender differences in cardiovascular and metabolic responses to cold and exercise. Canadian Journal of Physiological Pharmacology 65: 165–171, 1987. CrossRef
- Therminarias A, Flore P, Oddou-Chirpaz MF, Pellerei E, Quirion A. Influence of cold exposure on blood lactate response during incremental exercise. European Journal of Applied Physiology 58: 411–418, 1989. CrossRef
- Thorp JW, Mittleman KD, Haberman KJ, House JF, Doubt TJ. Work enhancement and thermal changes during intermittent work in cool water after carbohydrate loading, Technical Report 90–14, Naval Medical Research Institute, Bethesda, 1990.
- Timmons BA, Araujo J, Thomas TR. Fat utilization enhanced by exercise in a cold environment. Medicine and Science in Sports and Exercise 17: 673–678, 1985. CrossRef
- Toner MM, Sawka MN, Foley ME, Pandolf KB. Effect of body mass and morphology on thermal responses in water. Journal of Applied Physiology 60: 521–525, 1986 Toner MM, Sawka MN, Holden WL, Pandolf KB. Comparison of thermal responses between rest and leg exercise in water. Journal of Applied Physiology 59: 248–253, 1985.
- Toner MM, Sawka MN, Pandolf KB. Thermal responses during arm and leg and combined arm-leg exercise in water. Journal of Applied Physiology 56: 1355–1360, 1984. CrossRef
- Veicsteinas A, Ferretti G, Rennie DW. Superficial shell insulation in resting and exercising men in cold water. Journal of Applied Physiology 52: 1557–1564, 1982.
- Young AJ, Sawka MN, Neufer PD, Muza SR, Askew EW, Pandolf KB. Thermoregulation during cold water immersion is unimpaired by low muscle glycogen levels. Journal of Applied Physiology 66: 1809–1816, 1989.
- Physiology of Exercise in the Cold
Volume 11, Issue 6 , pp 367-381
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- 1. Hyperbaric Environmental Adaptation Program, Naval Medical Research Institute, Bethesda, Maryland, 20814, USA