Sweat or perspiration, the process of sweating, is the release of liquid from the body's sweat glands. It's a process control by your nervous system to help control and regulate your body temperature. The human body can have anywhere from two to five million sweat glands located all over your body (Except the lips, nipples and genitals-- it's true. Who knew?).
While sweating can occur for many different reasons they usually fall into one of two categories. According to the wonderful wikipedia, the two situations that stimulate sweating are, "during physical heat and during emotional stress. In general, emotionally induced sweating is restricted to palms, soles, armpits, and sometimes the forehead, while physical heat-induced sweating occurs throughout the body."
Unfortunately sweat isn't "your fat crying" and doesn't mean fat loss. I wish it did. Really, I do. It's truthfully made up mostly of water but contains some minerals like salt-which can vary, electrolytes, and a few other trace elements.
The truth is, how much you sweat during exercise is based on the external temperature (outside or in the room your exercising in), genetics, number of sweat glands and fitness levels. This may explain why some can break a sweat doing light house work and others can lift hundreds of pounds without sweating at all. As Jenny Scott, Education Advisor on the National Academy of Sports Medicine explained in an article with Health Magazine, "Our bodies produce sweat as a way to cool down, so if anything, it's an indicator of how hot your body is.".
Think of it this way, run five miles in the dessert and you'll probably sweat a ton. Run five miles in the middle of Winter in Alaska and you may not sweat at all. Is the dessert workout more beneficial because you sweat more? Nope.
As I mentioned above, sweat is made up mostly of water which means wearing heavy clothing to increase sweating will only help you to drop water weight. As soon as you rehydrate yourself the weight you may have lost via sweating should come back immediately.
Aside from the temporary weight loss resulting from an increase in perspiration, exercising in heavy, unbreathable clothing to drop weight can be dangerous and lead to dehydration. I know Rocky made it look cool but lets save the heavy sweats and track suits to wrestlers, boxers and powerlifters trying to cut weight for competition, ok? As a rule of thumb, consuming eight ounces of water every 15 minutes during activity should help you to avoid dehydration.
Another common thought about sweat is that it helps to detoxify our bodies. I'll be honest, I did my best to find scientific research to back this theory up and it sounds like the jury is still out on this one. Sweat has been shown to contain a tiny amount of toxins but it's not your sweat glands responsibility to detoxify your body (it's your liver and kidney's job). Sweating does have benefits but I'm not quite ready to brag about it's detoxifying powers just yet.
Your turn: Are you a sweater? (I am, my hands and feet are constantly sweating!)