This question must have come up once or twice during our recent heat wave. The answer is 25 degrees C (77 F). Researchers have discovered that beyond that temperature, the atmosphere can’t dissipate the perspiration we secrete fast enough to avoid overheating. Sweating is our body’s answer to heat, but for it to work, the perspiration must be naturally drawn away by the environment. Scientists have quantified the fact that each gram of sweat that transitions from a liquid to a gas; like when a breeze evaporates the moisture on your brow, it absorbs 2,427 joules of energy from the body and dissipates the heat into the atmosphere. That’s pretty cool, man.
This, of course, means that sweating on hot days is a good thing. Unfortunately, many don’t associate perspiration with other good things, such as ice cream. However, when it’s hot out you’re better to leave the sweat on unless it’s running off you. At that point the cooling effect is negligible and a quick dab with a towel might be in order. Wiping all the moisture off, however, robs the body of its cooling effect until the glands responsible can create more liquid to be evaporated away.
People are uncomfortable about sweat because they are concerned about the odor. The fact is perspiration has no odour at all. It’s only when bacteria has had time to begin digesting the sweat and discharging the unused material. In other words, what we actually smell is bacteria poop.
Yet another reason to stay cool.