To sweat or not to sweat?

Saunas, steam rooms and plastic sauna suits are all designed to do the same thing: make you sweat without exercising. But to what end?

Jon Schroeder sits in the sauna at a St Louis-area YMCA for 10 to 12 minutes a few times a week after working out.

To him, it just plain feels good.

"In the winter especially, it's nice to work up a sweat," Mr Schroeder (68), of St Louis, said.

He says he has no idea whether it has any benefit beyond that.

Websites and spas insist sweating rids the body of toxins.

Native Americans and New Age disciples believe that visions during sweat-lodge ceremonies lead to enlightenment.

Four months ago, self-help guru and best-selling author James Arthur Ray led more than 50 people into a makeshift sweat lodge near Sedona, Arizona, for a ceremony he said would cleanse their minds, spirits and bodies.

By the end of the ceremony, people were vomiting and passing out.

Three of them died and 19 were treated for burns, dehydration, kidney failure and respiratory arrest.

Recently, Ray was arrested and charged with three counts of manslaughter in connection with the deaths.

Medical experts stress there is a lot of misinformation about the benefits of sweating.

Essentially, its function is to cool the body and that's it, they say.

"Don't believe everything you read or hear," says Dr Dee Anna Glaser, professor of dermatology at St Louis University.

She has been studying sweat for years and chuckles when asked about the benefits of spending time in a sauna or spa.

There really are no medical benefits, she says.

The liver and kidneys do such a good job of ridding the body of toxins, there is almost none left for the sweat glands to purge.

"I think people find it relaxing because it causes you to sit for a moment, and the heat feels good and relaxation is not a bad thing," says Dr Glaser.

"But there's not a specific health benefit. You could probably sit on a couch in a nice quiet room and get the same benefits."

For people with certain skin conditions, sitting on a couch and chilling may be preferable to sitting in a sauna and sweating.

Dr Glaser urges anyone with broken capillaries, melasma (discoloured skin patches) and some types of acne to stay out of heat because it exacerbates those conditions.

"It also can break down collagen which gives skin thickness and fullness."

Dr Rob Poirier, clinical chief of emergency medicine at Washington University, has not seen any cases of heat exhaustion, heat stroke or death from steam rooms or saunas recently.

Most people, he says, know when to get out.

People will use saunas and steam rooms for years with no problems, because, like Mr Schroeder, they use common sense.

But, Dr Poirier notes, steam rooms can pose a higher risk of dehydration than saunas, which provide dry heat.

"The more humid it is, the less you sweat," says Dr Poirier.

"Sweat evaporates to cool you. When it doesn't evaporate, such as in a steam room, there's no cooling going on."

People who take diuretics to treat high blood pressure are more predisposed to dehydration and, in extreme cases, heat exhaustion and heat stroke, he says.

So are people who are hungover from drinking too much alcohol.

"People who drink heavily the night before can be slightly dehydrated, which is why you feel hungover," he says.

"Anyone with not a lot of fluid in their body will be more prone to going into heat exhaustion or heat stroke.

Plus, you won't necessarily feel your body getting sick as quickly as it's experiencing it."