Sweat is a hypotonic fluid excreted by sweat glands to cool the body. There are conflicting reports on whether or not body composition has an effect on thermoregulatory responses especially during exercise. This study was aimed at determining and comparing sweat rate and electrolyte composition in underweight (BMI < 18.5 kg/m2), normal weight (18.5 kg/m2 > BMI < 25 kg/m2), overweight (25kg/m2 < BMI < 30 kg/m2) and obese women (BMI > 30 kg/m2) during moderate exercise. Forty women (19 - 25 years) were used during this study after assessing their health status. They were stratified for BMI with each group having a total of ten women. It was ensured that all the women used in the study were euhydrated before commencing the research. Before sweat collection, the treadmill was calibrated according to the Bruce Treadmill Protocol. Sweat samples were obtained with a sweat suction apparatus from a 120 cm2 circular area marked on the skin of the face and neck, after a 15 minute fast walk on a treadmill at an inclination of 15° and at a speed of 4.2 km/h at 27°C room temperature. The time at which sweating commenced in the subjects was recorded. Sweat rate (L/hour) was calculated using the formula: sweat rate (L/hr) = (pre-exercise body weight - Post-exercise body weight)/exercise duration. Each sweat sample was collected and analysed immediately. The results showed that obese women had a significantly (P < 0.05) higher sweat rate and underweight women had a significantly (P < 0.05) lower sweat rate than all the other groups. Furthermore, subjects with a high body surface area showed significantly higher sweat rates compared to subjects with lower body surface area. Sweat electrolyte composition did not change in all BMI groups. In conclusion, obese subjects are more likely to develop fluid imbalances than underweight and normal weight subjects during moderate exercise. Also, underweight women might be at a thermoregulatory disadvantage because of their reduced body fat and body surface area.
References
[1]
IUPS Thermal Commission (2001) Glossary of Terms for Thermal Physiology. Japanese Journal of Physiology, 51, 245-280.
[2]
Aragon-Vagas, L.F. (2010) Workshop: Sweat Rate Measurement in Athletes. XXXI sFIMS Sports Medicine World Congress Medimond International Proceedings, San Juan, May 2010, 9-14.
[3]
Robinson, S. (1942) The Effect of Body Size upon Energy Exchange in Work. American Journal of Physiology, 36, 363-368.
[4]
Amabebe, E., Omorodion, S.I., Ozoene, J.O. and Ugwu, A.C. (2014) Relationship between Menopausal Sweating and Body Mass Index. Open Journal of Endocrine and Metabolic Diseases, 4, 137-146. http://dx.doi.org/10.4236/ojemd.2014.46014
[5]
Amabebe, E., Omorodion, S.I., Ozoene, J.O., Ugwu, A.C. and Obika, L.F. (2013) Sweating and Thirst Perception in Premenopausal, Perimenopausal and Postmenopausal Women during Moderate Exercise. Journal of Experimental and Integrative Medicine, 3, 279-284. http://dx.doi.org/10.5455/jeim.280813.or.087
[6]
Sato, K. (1977) The Physiology, Pharmacology and Biochemistry of the Eccrine Sweat Gland. Reviews of Physiology, Biochemistry and Pharmacology, 79, 51-31. http://dx.doi.org/10.1007/bfb0037089
[7]
Bijman, J. and Quinton, P.M. (1984) Influence of Abnormal Cl Impermeability on Sweating in Cystic Fibrosis. American Journal of Physiology-Cell Physiology, 247, C3-C9.
[8]
Inoue, Y., Nakao, M., Ishizashi, H., Tsujita, J. and Araki, T. (1998) Regional Differences in the Na+ Reabsorption of Sweat Glands. Applied Human Science, 17, 219-221. http://dx.doi.org/10.2114/jpa.17.219
[9]
Morgan, R.M., Patterson, M.J. and Nimmo, M.A. (2004) Acute Effects of Dehydration on Sweat Composition in Men during Prolonged Exercise in the Heat. Acta Physiologica Scandinavica, 182, 37-42. http://dx.doi.org/10.1111/j.1365-201x.2004.01305.x
[10]
Yoshida, T., Shinya, H., Nakai, S., Yorimoto, A., Morimoto, T., Suyama, T. and Sakurai, M. (2006) Genomic and Non-Genomic Effects of Aldosterone on the Individual Variation of the Sweat Sodium Ion Concentration during Exercise in Trained Athletes. European Journal of Applied Physiology, 98, 466-471. http://dx.doi.org/10.1007/s00421-006-0295-5
[11]
Buono, M.J., Ball, K. and Kolkhorst, F. (2007) Sodium Ion Concentration vs. Sweat Rate Relationship in Humans. Journal of Applied Physiology, 103, 990-994. http://dx.doi.org/10.1152/japplphysiol.00015.2007
[12]
Ugwu, A.C. and Oyebola, D.D.D. (1992) Effects of Temperature and Exercise on Sweat Rate and Sweat Electrolyte Loss in Nigerians. Nigerian Journal of Physiological Sciences, 8, 92-101.
[13]
Leites, G.T., Sehl, P.L., Cunha, G.S., Detoni, F.A. and Meyer, F. (2013) Responses of Obese and Lean Girls Exercising under Heat and Thermoneutral Conditions. The Journal of Pediatrics, 162, 1054-1060. http://dx.doi.org/10.1016/j.jpeds.2012.10.047
[14]
Limbaugh, J.D., Wimer, G.S., Long, L.H. and Bard, W.H. (2013) Body Fatness, Body Core Temperature and Heat Loss during Moderate-Intensity Exercise. Aviation, Space, and Environmental Medicine, 84, 1153-1158. http://dx.doi.org/10.3357/ASEM.3627.2013
[15]
Eijsvogels, T.M.H., Veltmeijer, M.T.W., Schreuder, T.H.A., Poelkens, F., Thijssen, D.H.J. and Hopman, M.T.E. (2011) The Impact of Obesity on Physiological Responses during Prolonged Exercise. International Journal of Obesity, 35, 1404-1412. http://dx.doi.org/10.1038/ijo.2010.277
[16]
WHO Expert Consultation (2004) Appropriate Body-Mass Index for Asian Populations and Its Implications for Policy and Intervention Strategies. Lancet, 363, 157-163.
[17]
Sawka, M.N., Burke, L.M., Eichner, E.R. and Maughan, R.J. (2007) American College of Sports Medicine Positions Stand. Exercise and Fluid Replacement. Medicine and Science in Sports and Exercise, 39, 377-390.
[18]
Ugwu, A.C. and Oyebola, D.D.O. (1996) Sweat Collection Made Simple. Journal of Medical Laboratory Science, 5, 171-176.
[19]
Mostellar, R.D. (1987) Simplified Calculation of Body Surface Area. New England Journal of Medicine, 317, 1098. http://dx.doi.org/10.1056/NEJM198710223171717
[20]
Bruce, R.A., Blackman, J.R., Jones, J.W. and Straty, G. (1963) Exercise Testing in Adult Normal Subjects and Cardiac Patients. Pediatrics, 32, 742-756.
[21]
Ugwu, A.C. (1985) Cardio-Respiratory Changes in Nigerians Sweating under Heat and Exercise Conditions. International Journal of Research Communication Systems, 13, 563-564.
[22]
Ugwu, A.C. (1985) Sex Differences in Sweat Rates and Composition in Human Populations Indigenous to a Tropical Hot Humid Climate. International Journal of Research Communication Systems, 13, 938-939.
[23]
Ugwu, A.C. (1985) Differences between Sweating Characteristics of Men and Women of Tropical Hot and Humid Climates. International Journal of Research Communication Systems, 13, 1118-1119.
[24]
Ugwu, A.C. (1986) The Time Course of Sweat Excretion Among Men of Tropical Hot and Humid Climates. International Journal of Research Communication Systems, 14, 459-460.
[25]
Ugwu, A.C. (1987) Calcium and Magnesium Concentrations in Sweat of Normal Nigerian Men Sweating under Heat and Exercise Conditions. Medical Science Research Journal, 15, 1249-1250.
[26]
Casa, D.J., Armstrong, L.E., Hillman, S.K., Montain, S.J., Reiff, R.V., Rich, B.S., Roberts, W.O. and Stone, J.A. (2000) National Athletic Trainers’ Association Position Statement: Fluid Replacement for Athletes. Journal of Athletic Training, 35, 212-224.
[27]
Kolka, M.A. (1992) Temperature Regulation in Women. Medicine, Exercise, Nutrition and Health, 1, 201-207.
[28]
Mecklenburg, R.S., Loriaux, D., Lynn, D.L., Thompson, R.H., Andersen, A.E. and Lipsett, M.B. (1974) Hypothalamic Dysfunction in Patients with Anorexia Nervosa. Medicine, 53, 147. http://dx.doi.org/10.1097/00005792-197403000-00003
[29]
Havenith, G. and van Middendorp, H. (1990) The Relative Influence of Physical Fitness, Acclimatization State, Anthropometric Measures and Gender on Individual Reactions to Heat Stress. European Journal of Applied Physiology and Occupational Physiology, 61, 419-427.
[30]
Taylor, N.A.S. (1986) Eccrine Sweat Glands: Adaptations to Physical Training and Heat Acclimation. Sports Medicine, 3, 387-397. http://dx.doi.org/10.2165/00007256-198603060-00001
[31]
Saat, M., Sirisinghe, R.G., Singh, R. and Tochihara, Y. (2005) Effects of Short-Term Exercise in the Heat on Thermoregulation, Blood Parameters, Sweat Secretion and Sweat Composition of Tropic-Dwelling Subjects. Journal of Physiological Anthropology and Applied Human Science, 24, 541-549. http://dx.doi.org/10.2114/jpa.24.541
[32]
Shamsuddin, A.K.M., Yanagimoto, S., Kuwahara, T., Zhang, Y., Nomura, C. and Kondo, N. (2005) Changes in the Index of Sweat Ion Concentration with Increasing Sweat during Passive Heat Stress in Humans. European Journal of Applied Physiology, 94, 292-297. http://dx.doi.org/10.1007/s00421-005-1314-7
[33]
Nejsum, L.N., Practorius, J. and Nielsen, S. (2005) NKCC1 and NHE1 are Abundantly Expressed in the Basolateral Plasma Membrane of the Secretory Coil Cells in Rat, Mouse and Human Sweat Glands. American Journal of Physiology-Cell Physiology, 289, C333-C340. http://dx.doi.org/10.1152/ajpcell.00228.2004
[34]
Pichan, G., Gauttam, R.K., Tomar, O.S. and Bajaj, A.C. (1988) Effect of Primary Hypohydration on Physical Work Capacity. International Journal of Biometeorology, 32, 176-180. http://dx.doi.org/10.1007/BF01045276
[35]
Haymes, E.M., McCormick, R.J. and Buskirk, E.R. (1975) Heat Tolerance of Exercising Lean and Obese Prepubertal Boys. Journal of Applied Physiology, 39, 457-461. http://dx.doi.org/10.1249/00005768-197500710-00082
