You've heard it all before: sweating rids the body of toxins and helps with weight loss, a reason people have been flocking to all those hot yoga classes and melting in saunas.
Heat is touted as a therapy to raise the heart rate and increase circulation, and you now have your choice of sweatboxes, from smoke saunas to electric, continuous-fire and the one I've been hearing about most, infrared.
"Sweat, sweat it's good for you," say the perspiration pushers.
But can you really swelter your way to better health?
What the experts say
"In general, sweating does not have detoxifying effects. Certain medical conditions cause elimination of certain products via the sweat. During kidney failure, urea products are sometimes excreted through sweat. Can sweating detoxify, aside from under specific conditions? No. The central body feedback is just not hooked up enough to the sweat glands, so they've got a limited way that they can respond. The kidneys and liver have a very complicated apparatus to get rid of what we would call toxins. Sweat glands are relatively simple and do not have the associated mechanisms.'
JOHN GOLDHAR , dermatologist, medical director, CosMedix MD, Toronto
"The infrared sauna is more like the heat from the sun than a regular thermal sauna. You don't feel as hot, but the heat penetrates deeper into the body. Sweating works to rid the body of toxins that lodge themselves in the fat cells. It's one of the best and least invasive ways to remove them from our system. Sauna therapy is great for couples planning to have babies, to get their bodies in tip-top, toxin-free shape. It's also good for weight loss. It's helpful for smokers or welders. Sometimes people will notice that their towel is yellow or even black from the sweat they are wiping off their bodies. It's especially good to do a detox after a weekend of partying."
GISELLE LILY LEFEBVRE , naturopath, Toronto
"There are a lot of claims that sweating detoxifies the body by getting rid of unwanted compounds, be they heavy metals or drugs, but I don't think we know whether these claims are true. It's possible that some things can be excreted in sweat: sodium chloride and potassium. But I don't think it's been studied enough. Can you get rid of, say, excess magnesium through a sauna? We don't have that information. And alcohol? I don't think so."
ERIC GOLDSTEIN , dermatologist, Toronto
"The body has different ways of getting rid of the junk: coughing, bowel movements, sweat. We don't always use these ways of eliminating things in the most effective manner. I'm not a scientist, so this is coming from what I have noticed in my own practice. When we are sweating, we try to stop quickly so our pores don't get the chance to really cleanse out what is inside the skin and the body. Sitting in a sweat lodge, you're going to get rid of chemicals -- sweat obviously has a lot of chemicals in it. It's like wringing out a soaking wet towel rather than letting it drip dry."
CELESTE DIXON , manager, Moksha Yoga Danforth, Toronto
"If you lose weight through sweat loss, it's because the sweat weighs something. You will lose weight temporarily until you replace that water. There are all sorts of myths that sweating will melt fat, but it doesn't work that way. Weight loss comes from burning fat as fuel or lack of caloric intake. The worry is that people will go to extremes with excessive sweating. Water loss can be dangerous. Dehydrating is not good for the body -- [especially] for the cardiovascular system. If you go into a sauna and don't replace that water afterwards, it can be a problem.'
JACK GOODMAN , associate professor, faculty of physical education and health, U of T