Leonardo Gomes Martins Coelho

Head Hair Reduces Sweat Rate During Exercise Under the Sun

The purpose of this study was to evaluate the effects of human head hair on thermoregulation during exercise carried out under solar radiation. 10 healthy male subjects (mean±SD: 25.1±2.5 yr; height: 176.2±4.0 cm; weight: 73.7±6.7 kg; VO(2max) 56.2±5.3 mLO(2)·kg (-1)·min (-1)) took part in 2 1 h-long trials of continuous exercise on a treadmill at 50% VO2(max) under solar radiation that were separated by at least 2 days. Whereas for the first trial they retained their natural head hair (HAIR), in the second trial their hair was totally shaved (NOHAIR). Several properties were measured, including environmental heat stress (Wet Bulb Globe Temperature index - WBGT, °C), heart rate, rectal temperature, skin temperature, head temperature, and global sweat rate. The main findings were that whereas there was a lower sweat rate in the HAIR condition (HAIR: 7.08±0.79 vs. NOHAIR: 7.67±0.79 g·m (-2)·min (-1); p=0.03), there were no significant differences in any of the other variables between the HAIR and NOHAIR trials. In conclusion, the presence of head hair resulted in a lower sweat rate.

Distribuição regional do suor durante exercício progressivo até a fadiga

Considering the hypothesis of human selective brain cooling during exercise should depend on greater sweating mechanism in the forehead. The purpose of this study was verify variations of sweat production between body regions during progressive exercise until fatigue (PEF). Seventeen subjects (23 ± 2 years old, 76.93 ± 7.74 kg, 179 ± 7 cm and 1.9 ± 0.1 m2) volunteered for this study. Local sweat rate (STlocal), number of active sweat glands (ASG) and sweat rate for ASG (STlocal.ASG-1) in eight body regions (forehead, back, chest, arm, forearm, hand, leg and calf) were measured during PEF in cyclergometer. The STlocal of the forehead was higher than in all others regions and the chest STlocal was higher only than the leg. The number of ASG in the forehead was greater than in all other regions, and the ASG of the hand was higher than those of the chest, arm, leg and calf. The STlocal.ASG-1 of the forehead was higher than the arm, forearm, hand and leg, and the STlocal. ASG-1 of the chest and back were higher than the forearm and hand. The sweat production of the upper body (forehead, back, chest, arm, forearm and hand) was bigger than the lower body (leg and calf). In conclusion, the PEF promoted a sweating pattern in body regions that can be related to the higher convection present in the upper regions of the body.

ANÁLISE DAS CAPACIDADES FÍSICAS DE CRIANÇAS DOS SETE AOS DEZ ANOS DE IDADE

Resumo: Desempenho motor e o termo utilizado para agrupar as capacidades forca, velocidade, resistencia, flexibilidade e coordenacao. O desempenho motor de criancas e preocupacao permanente entre os especialistas da area da saude. Esse interesse justifica-se ja que a atividade fisica desempenha importante papel na prevencao de doencas e melhoria da capacidade funcional. O objetivo do presente estudo foi avaliar a capacidade motora em criancas de ambos os sexos. Apos consentimento por escrito dos pais, participaram do estudo 232 criancas de ambos os sexos entre as idades de sete e 10 anos. O desempenho motor foi avaliado utilizando-se os testes de sentar e alcancar, resistencia abdominal, salto horizontal e corrida de 30 metros. Foi utilizado ANOVA two way e post hoc de Tukey para comparacao das variaveis entre as idades e o sexo. O nivel de significância foi de 5%. A flexibilidade nao foi modificada pela idade e sexo (p > 0,05). O salto horizontal e o numero de abdominais foram maiores nos meninos comparados as meninas e nas idades de 10, nove e oito anos comparados a idade de sete anos (p < 0,001). O tempo para percorrer 30 m foi menor nos meninos comparado as meninas (p < 0,001), sendo que a idade de 10 anos apresentou valores menores comparado as demais idades e as idades de nove e oito anos demonstraram menores valores comparado a idade de sete anos (p < 0,001). De modo geral, os meninos apresentam melhor desempenho motor comparado as meninas na faixa etaria avaliada. A idade de sete anos parece representar um periodo de transicao no desempenho motor.