Cardiovascular responses of physically active colligate subjects during normal and warm conditions, and determination of sweat rates

Yıl 2014, Cilt: 16 Sayı: 1, 135 - 139, 05.06.2014

Bilal Demırhan Asim Cengız , Bade Tekbas

Öz

The aim of this study was to determine the effects of elevated climate temperature on the exercise-induced physiological responses and fluid need in physically active subjects. Ten physically active colligate subjects (age: 22.79 ± 4.98 yrs) participated in a counter balanced cross over design that consisted of performing a cycling run (65% VO2 max) for 30 min under normal and condition of wearing multiple layers of clothes, separated by 7 days. Measures of heart rate, body temperature, and rating of perceived exertion (RPE) were obtained at 10-min intervals (0, 10, 20, and 30 min) from the onset of exercise.  Sweat rates, and amount of fluid needed to replace water loss during exercise were calculated. Heart rate, body temperature, and RPE increased all the way to the end of the exercise for both conditions but more in warm conditions. These findings point out that sports facilitators should take the athletes' physiological responses in training in warm dry weather seriously, guide athletes to rehydrate with adequate amount of water.

Anahtar Kelimeler

Running, heat, and sweat rate.

Kaynakça

• American College of Sports Medicine. Guidelines for Exercise Testing and Prescription. Lippincott Williams and Wilkins, Baltimore, 2000.
• Bynum GD, Pandolf KB, Schuette WH, Goldman RF, Lees DE, Whang-Peng J, Atkinson ER, Bull JM. Induced hyperthermia in sedated humans and the concept of critical thermal maximum. Am J Physiol Regul Integr Comp Physiol, 1978; 235: R228–R236.
• Dessai S. Heat stress and mortality in Lisbon Part I. model construction. Int J Biometeorol, 2002; 47: 6–12.
• Environmental Physiology, ed. Fregly MJ & Blatteis CM, chapt 11, pp. 215–243. Oxford University Press, New York, 1996.
• Ekelund LG. Circulatory and respiratory adaptation during prolonged exercise. Acta Physiol Scand, 1967; 70 (Suppl. 68), 5– 38.
• Galloway SD. Dehydration, rehydration, and exercise in the heat: Rehydration strategies for athletic competition. Can J Appl Physiol, 1999; 24(2): 188-200.
• Grosman B, Shaik OS, Helwig BG, Leon LR, Doyle III FJ. A physiological systems approach to modeling and resetting of mouse thermoregulation under heat stress. J Appl Physiol, 2011; 111: 938–945.
• González-Alonso J, Teller C, Andersen SL, Jensen FB, Hyldig T, Nielsen B. Influence of body temperature on the development of fatigue during prolonged exercise in the heat. J Appl Physiol, 1999; 86: 1032–1039.
• Gonz´alez-Alonso J. Hyperthermia impairs brain, heart and muscle function in exercising humans. Sports Med, 2007; 37: 371–373.
• Gonz´alez-Alonso J, Calbet JA. Reductions in systemic and skeletal muscle blood flow and oxygen delivery limit maximal aerobic capacity in humans. Circulation, 2003; 107: 824–830.
• Hargreaves M, Dillo P, Angus D, Howlett K, Conus NM, Febbraio M. Effect of fluid ingestion on muscle metabolism during prolonged exercise. J Appl Physiol, 1996; 81: 1594–1597.
• Johnson JM. Exercise and the cutaneous circulation. Exerc Sports Sci Rev, 1992; 20: 59–97.
• Johnson JM, Proppe DW. Cardiovascular adjustments to heat stress. In Handbook of Physiology, section 4, 1996.
• Johnson JM, Rowell LB. Forearm skin and muscle vascular responses to prolonged leg exercise in man. J Appl Physiol, 1975; 39: 920–924.
• Kenefick RW, Cheuvront SN. Hydration for recreational sport and physical activity. Nutr Rev, 2012; 70 (Suppl. 2): S137-142.
• Montain SJ, Coyle EF. Influences of grade dehydration on hyperthermia and cardiovascular drift during exercise. J Appl Physiol, 1992; 73: 1340–1350.
• Murray B. Hydration and physical performance. Journal of the American College of Nutrition, 2007; 26(5): 542S–548S.
• Nybo L. Brain temperature and exercise performance. Exp Physiol, 2012; (3): 333-339.
• Keller DM, Cui J, Davis SL, Low DA, Crandall CG. Heat stress enhances arterial baroreflex control of muscle sympathetic nerve activity via increased sensitivity of burst gating, not burst area, in humans. J Physiol 2006; 573: 445–451.
• Kellogg DL Jr, Johnson JM, Kenny WL, P´ergola PE, Kosiba WA. Mechanisms of control of skin blood flow during prolonged exercise in humans. Am J Physiol Heart Circ Physiol, 1993; 265: H562–H568.
• Kellogg DL Jr, Johnson JM, Kosiba WA. Elevation of the threshold vasodilation by dynamic exercise. J Appl Physiol, 1991; 71: 2476–2482. for active cutaneous
• Kellogg DL Jr, P´ergola PE, Kosiba WA, Grossmann M, Johnson JM. Cutaneous active vasodilation in humans is mediated by cholinergic nerve co-transmission. Circ Res, 1995; 77: 1222–1228.
• Maughan RJ, Shirre M. Dehydration and rehydration in competitive sport. Scand J Med SciSports, 2010; (Suppl 3): 40-47.
• Smolander J, Saalo J, Korhonen O. Effect of workload on cutaneous vascular response to exercise. J Appl Physiol, 1991; 71: 1614–1619.