Sweating economy by graded control in well-trained athletes

Local sweat rates (Msw) at the chest and thigh and the frequency of sweat expulsions (Fsw) were determined in human subjects with (athletes) or without (non-athletes) long-term physical training during moderate bicycle exercise (80 W for 30 min) at ambient thermoneutrality (23 degrees C) and 60% relative humidity. There was a tendency for Msw to be lower in athletes. The rise of Msw with increasing Fsw was significantly less steep and Fsw was also controlled at a significantly lower rate in athletes than in non-athletes. The start of exercise was followed by a temporary decrease in mean skin temperature (Ts) which was less distinct in athletes. The rise in Ts at the end of exercise was significant in athletes (0.80 +/- 0.26 degree C) but not in non-athletes (0.26 +/- 0.33 degree C). The results indicate that long-term physical training leads to improved circulatory heat transfer to the skin and to a more graded nervous control of sweat expulsion and, further, tends to reduce the rate of sweating.