Summary
This study examines the relationships between vascular changes and endocrine responses to prolonged exercise in the heat, associated with dehydration and rehydration by fluids of different osmolarity. Five subjects were exposed, in a 34‡ C environment for 4 h of intermittent exercise on a cycle ergometer at 85±12 Watts (SD). Fluid regulatory hormones and cortisol were analysed in 3 experimental sessions: one without any fluid supplement (NO FLUID), and two with progressive rehydration, either by spring water (WATER) or isotonic solution (ISO), given after 70 min of exercise. Results were expressed in terms of differences between the mean values observed at the end of the exercise and the first hour values taken as references.
Dehydration (NO FLUID) elicited a 4.0±0.8% (SE) decrease in plasma volume (PV) and an increase in osmolarity (8.4±3.1 mosmol · l−1). Concomitantly, plasma aldosterone (PA), renin activity (PRA), arginin vasopressin (AVP) and cortisol (PC) levels increased greatly in response to exercise in the heat (PA: 37.2+-10.8 ng. 100 ml−1; PRA: 13.4±2.5 ng · ml−1 · h−1; AVP: 3.8±1.3 pg · ml−1; PC: 12.2±2.7 Μ g · 100 ml−1). Rehydration with water led to decreased osmolarity (−8.2±2.1 mosmol · l−1) with no significant changes in PV. With ISO, PV increased by 6.0±1.3% and the decrease in osmolarity was −5.8±1.8 mosmol · l−1. With both modes of rehydration, the increases in PRA, AVP and cortisol were blunted; only ISO prevented the rise in PA.
These data indicate that prolonged exercise in moderate heat is extremely effective in increasing cortisol and fluid-electrolyte regulatory hormones in dehydrated subjects. Progressive rehydration with water or isotonic solution, in the absence of osmotic and volemic stimuli, prevents the hormonal increases.
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References
Bonner RM, Harrison MH, Hall CJ, Edwards RJ (1976) Effect of heat acclimatization on intravascular responses to acute heat stress in man. J Appl Physiol 41:708–713
Brandenberger G (1985) Cortisol responses to exercise and their interactions with diurnal secretory peaks. In: Fotherby K, Pal SB (ed) Exercise endocrinology. Walter de Gruyter and Co. Berlin, New York, pp 47–64
Brandenberger G, Follenius M, Oyono S (1980) Effect of propranolol on aldosterone response to heat exposure in sodium-restricted men. J Endocrinol Invest 4:395–400
Caillens H, Pruszczinski W, Meyrier A, Ang KS, Rousselet F, Ardaillou R (1980) Relationship between change in volemia at constant osmolarity and plasma antidiuretic hormone. Mineral Electrolyte Metab 4:161–171
Candas V, Libert JP, Brandenberger G, Sagot JC, Amoros C, Kahn JM (1986) Hydration during exercise: effects on thermal and cardiovascular adjustments. Eur J Appl Physiol 55 (in press)
Claremont AD, Costill DL, Fink W, Van Handel P (1976) Heat tolerance following diuretic induced dehydration. Med Sci Sports 8:239–243
Coghlan JP, Blair-West JR, Denton DA, Fei DT, Fernley RT, Hardy KJ, McDougall JG, Puy R, Robinson PM, Scoggins BA, Wright RD (1979) Control of aldosterone secretion. J Endocrinol 81:55–65
Collier JG, Keddie J, Robinson BF (1975) Plasma renin activity during and after dynamic and static exercise. Cardiovasc Res 9:323–326
Collins KJ, Few JD (1979) Secretion and metabolism of cortisol and aldosterone during controlled hyperthermia. J Physiol (Lond) 292:1–14
Convertino VA, Brock PJ, Keil LC, Bernauer EM, Greenleaf JE (1980) Exercise training-induced hypervolemia: role of plasma albumin, renin and vasopressin. J Appl Physiol: Respirat Environ Exercise Physiol 48:665–669
Convertino VA, Keil LC, Bernauer EM, Greenleaf JE (1981) Plasma volume, osmolarity, vasopressin, and renin activity during graded exercise in man. J Appl Physiol: Respirat Environ Exercise Physiol 50:123–128
Convertino VA, Keil LC, Greenleaf JE (1983) Plasma volume, renin and vasopressin responses to graded exercise after training. J Appl Physiol: Respirat Environ Exercise Physiol 54:508–514
Costill DL, Sparks KE (1973) Rapid fluid replacement following thermal dehydration. J Appl Physiol 34:299–303
Costill DL, Branam G, Fink W, Nelson R (1976) Exercise induced sodium conservation: changes in plasma renin and aldosterone. Med Sci Sports 8:209–213
Davies JA, Harrison MH, Cochrane LA, Edwards RJ, Gibson TM (1981) Effect of saline loading during heat acclimatization on adrenocortical hormone levels. J Appl Physiol: Respirat Environ Exercise Physiol 50:605–612
Dill DB, Costill DL (1974) Calculation of percentage changes in volumes of blood, plasma and red cells in dehydration. J Appl Physiol 37:247–248
Fagard R, Amery A, Reybrouck T, Lijnen P, Moerman E, Bogaert M, De Schaepdryver (1977) Effects of angiotensin antagonism on hemodynamics, renin, and catecholamines during exercise. J Appl Physiol: Respirat Environ Exercise Physiol 43:440–444
Finberg JPM, Katz M, Gazit H, Beriyne GM (1974) Plasma renin activity after acute heat exposure in nonacclimatized and naturally acclimatized man. J Appl Physiol 36:519–523
Follenius M, Brandenberger G, Reinhardt B, Simeoni M (1979) Plasma aldosterone, renin activity, and cortisol responses to heat exposure in sodium depleted and repleted subjects. Eur J Appl Physiol 41:41–50
Follenius M, Brandenberger G, Oyono S, Candas V (1982) Cortisol as a sensitive index of heat-intolerance. Physiol Beh 29:509–513
Francesconi RP, Sawka MN, Pandolf KB (1983) Hypohydration and heat acclimation: plasma renin and aldosterone during exercise. J Appl Physiol: Respirat Environ Exercise Physiol 55:1790–1794
Francis KT (1979) Effect of water and electrolyte replacement during exercise in the heat on biochemical indices of stress and performance. Aviat Space Environ Med 50:115–119
Francis KT, MacGregor R (1978) Effect of exercise in the heat on plasma renin and aldosterone with either water or a potassium-rich electrolyte solution. Aviat Space Environ Med 49:461–465
Gaebelein CJ, Senay LC (1980) Influence of exercise type, hydration, and heat on plasma volume shifts in man. J Appl Physiol: Respirat Environ Exercise Physiol 49:119–123
Gaebelein CJ, Senay LC (1982) Vascular volume changes during cycling and stepping in women at two hydration levels. Eur J Appl Physiol 48:1–10
Galbo H (1983) Hormonal and metabolic adaptation to exercise. Georg Thieme Verlag Stuttgart, New York
Gianotti P, Manneli M, Fiorelli G, Serio M (1974) Radioimmunoassay of plasma aldosterone. J Nucl Biol Med All Sci 18:104–108
Greenleaf JE, Sciaraffa D, Shvartz E, Keil LC, Brock PJ (1981) Exercise training hypotension: implications for plasma volume, renin, and vasopressin. J Appl Physiol: Respirat Environ Exercise Physiol 51:298–305
Haber E, Koerner R, Page LB, Kliman B, Purnode A (1969) Application of radioimmunoassay of angiotensin I to the physiologic measurements of plasma renin activity in normal human subjects. J Clin Endocrinol Metab 23:1349–1356
Harrison MH, Edwards RJ, Graveneu MJ, Cochrane LA, Davies JA (1981) Blood volume and plasma protein responses to heat acclimatization in humans. J Appl Physiol: Respirat Environ Exercise Physiol 50:597–604
Kosunen KJ, Pakarinen AJ (1976) Plasma renin, angiotensin II, and plasma and urinary aldosterone in running exercise. J Appl Physiol 41:26–29
Kosunen KJ, Pakarinen AJ, Kuoppasalmi AK, Adlercreutz H (1976) Plasma renin activity, angiotensin II, and aldosterone during intense heat stress. J Appl Physiol 41:323–327
Kotchen TA, Hartley LH, Rice TW, Nougey EM, Jones LG, Mason JW (1971) Renin, norepinephrine, and epinephrine responses to graded exercise. J Appl Physiol 31:178–184
Laragh JH (1977) An approach to the classification of hypertensive states. In: Davis JO, Laragh JH, Selwyn A (ed) Hypertension mechanisms, diagnosis and management. Hospital Practice, New York, pp 1–13
Melin B, Eclache JP, Geelen G, Annat G, Allevard AM, Jarsaillon E, Zebidi A, Legros JJ, Gharib C (1980) Plasma AVP, neurophysin, renin activity and aldosterone during submaximal exercise performed until exhaustion in trained and untrained men. Eur J Appl Physiol 44:151–161
Miles DS, Sawka MN, Glaser RM, Petrovfsky JS (1983) Plasma volume shifts during progressive arm and leg exercise. J Appl Physiol: Respirat Environ Exercise Physiol 54:491–495
Robertson GL, Athar S (1976) The interaction of blood osmolality and volume in regulating plasma vasopressin in man. J Clin Endocrinol Metab 42:613–620
Sawka MN, Francesconi RP, Pimental NA, Pandolf KB (1984) Hydration and vascular fluid shifts during exercise in the heat. J Appl Physiol: Respirat Environ Exercise Physiol 56:91–96
Senay LC, Jr (1975) Plasma volumes and constituents of heat-exposed men before and after acclimatization. J Appl Physiol 38:570–575
Senay LC Jr, Rogers G, Jooste P (1980) Changes in blood plasma during progressive treadmill and bicycle exercise. J Appl Physiol: Respirat Environ Exercise Physiol 49:59–65
Smiles KA, Robinson S (1971) Sodium ion conservation during acclimatization of men to work in the heat. J Appl Physiol 31:63–69
Sundsfjord JA, Stromme SB, Aakvaag A (1975) Plasma aldosterone (PA), plasma renin activity (PRA) and cortisol (F) during exercise. In: Howald H, Poortmans JR (ed) Metabolic adaptation to prolonged physical exercise. BirkhÄuser Verlag, Basel, pp 308–314
Vecsei P, Peuke B, Katzy R, Back L (1972) Radioimmunological determination of plasma cortisol. Experientia 8:1104–1106
Wade CE, Claybaugh JR (1980) Plasma renin activity, vasopressin concentration, and urinary excretory responses to exercise in men. J Appl Physiol: Respirat Environ Exercise Physiol 49:930–936
Wilkerson JE, Gretin B, Horvath SM (1977) Exercise-induced changes in blood, red cell, and plasma volumes in man. Med Sci Sports 9:155–158
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Brandenberger, G., Candas, V., Follenius, M. et al. Vascular fluid shifts and endocrine responses to exercise in the heat. Europ. J. Appl. Physiol. 55, 123–129 (1986). https://doi.org/10.1007/BF00714993
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DOI: https://doi.org/10.1007/BF00714993