Raspar a cabeça aumenta o estresse fisiológico em homens durante exercício sob o sol

AUTOR(ES)

Leonardo Gomes Martins Coelho

DATA DE PUBLICAÇÃO

2008

RESUMO

The purpose of the present study was to test the theory that human hair could represent a barrier to solar radiation, allowing minor physiological indices of heat stress during exercise in a hot environment under the sun. Participated in this study 10 male volunteers, inhabitants of tropical region, healthy and fit for the practice of physical exercises (25,1 ± 2,5 years old; 176,2 ± 4,0 cm of height; 73,7 ± 6,7 kg of weight; VO2max 56,2 ± 5,3 mL×kg-1×min-1). They had wavy or spiraled hair with a layer of at least three centimeters in thickness in the central head region. The volunteers participated in three experimental sessions. On the first day, after anthropometric characterization, a test to measure the aerobic capacity was done. After two days of the first meeting, individuals started the protocol which had two more experimental situations, compost continuous exercise in a treadmill with one hour of duration and intensity to 50% of VO2max. The inclination of treadmill was maintained at 1% during the entire protocol. First continuous exercise: in the external environment under the Sun, with the natural hair within the specified dimensions. Second continuous exercise: the volunteers had their hair totally scraped and repeated the exercise under the Sun. The protocols were separated by at least two days and at most a week. The environmental heat stress was measured by the Index of Wet Bulb Globe Temperature (WBGT) in º C and used as a co-variable if necessary. A physiological strain index (PSI), rectal temperature, heart rate (HR) and total rate of sweating was measured. The results showed greater PSI (ANCOVA, F = 5222, p = 0,035), greater delta of HR (ANCOVA, F = 29009, p = 0,0001) and greater total sweating rate (7,08 ± 0,25 vs. 7,67 ± 0,26, p = 0,30) in the situation with scraped hair. In conclusion, scratch the head increases the physiological stress index, variation in heart rate and total sweat hate.

ASSUNTO(S)

cabelo efeito fisiológico teses. corpo temperatura regulação teses. exercícios físicos aspectos fisiológicos teses. stress (fisiologia) testes teses. calor efeito fisiologico teses.

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