Q: I sweat profusely (literally dripping wet) during my aerobic workout. Is this an indication that I'm out of shape?

A: The reason for profuse sweating is that body core temperature becomes significantly elevated by the increase in metabolic heat production during exercise.

In response to an elevated body core temperature, the brain signals the body to dissipate the excess heat as rapidly as possible. Eccrine sweat glands are then activated, and fluid is transported to the skin so that it can evaporate and create a cooling effect.

Rather than indicating a lack of conditioning, sweat dripping off the body may be more indicative of the fact that the humidity of the environment is so high that sweat can't evaporate. All factors considered, this is not an ideal situation, because it may mean that the body is not being effectively cooled via evaporation.

On the other hand, profuse sweating can also be a sign of being relatively fit, since one of the adaptations to consistent exercise training is that individuals will sweat more and sweat sooner so that their bodies don't store extra heat.

Source: Bryant, Cedric X. 101 Frequently Asked Questions about "Health & Fitness" and "Nutrition & Weight Control". Sagamore Publishing, 1999.