There's nothing quite like the exhilarating feeling of stepping out of a hot sauna after a sweat session to enjoy that wall of cold air hitting your body.
It's invigorating. It's refreshing. But besides being sensorially pleasing, do saunas actually have any proven health benefits? And who conjured up the whole concept in the first place?
"'Sauna' is the only Finnish word that has been adopted around the world, and saunas and sweat lodges have been used traditionally in most cultures throughout history. They are used for many reasons, often as part of the culture and used for socialising, or they are used for ritual, or after childbirth."
Tradition aside, it's commonly believed that saunaing offers a host of health and wellbeing benefits.
"The health benefits of saunas aren't very well documented. The most research has been done on Finnish saunas and it's been done in conjunction with a look at cardiovascular disease," Cohen said.
"What they have found is that saunaing has a great benefit for people with heart failure, and there's a few reasons why that may be. When you're in a sauna your heart rate goes up, so you're getting a form of cardiovascular aerobic workout, however you're not having to exercise, and a lot of people with heart conditions can't exercise. While in a sauna, blood vessels are dilated and open, which improves circulation, and cardio output goes up and that's beneficial in people with heart failure."
Another reason is because being in a hot room like a sauna or steamroom makes you sweat.
"One of the things we have found is that sweat is probably the most least understood body fluid. We take urine samples and blood samples, but we vary rarely use sweat in medicine. Sweat varies enormously on different people and parts of the body, and there are at least four different types of sweat glands. But what we do know, and what's well documented is that sweating is very good for you," Cohen said.
"A recent study found that some toxins are preferentially excreted in sweat. We don't really know if the levels being released are significant for your body, but one of the principles for detoxification is keeping your channels of elimination open. Sweat is an important channel of elimination. By having water flow through your body and out your skin, it almost certainly will help you detox, but detox is a complicated other area."
A version of saunaing that's very popular among the wellness crowd right now is infrared saunas.
"There's very little research on infrared saunas, but infrared saunas are designed to make you sweat at a lower body temperature," Cohen said.
"In a Finnish sauna you get really hot, at anywhere from around 70, to 80 or 90 degrees, and for a lot of people that's hard to tolerate. Whereas with infrared saunas, the infrared energy penetrates into the tissue, so it allows you to sweat at a lower and much more comfortable temperate."
"Infrared energy is just heat, though there are different frequencies. The type of infrared rays used in saunas are 'FAR' rays, which heats up the water in your body, which is what you want if you want to sweat," Cohen said.
As for safety, saunas are relatively fine, but you need to be well hydrated and in-tune with your body.
"In terms of if saunaing is dangerous, there are some documented deaths, but most of them are linked to consuming alcohol. Alcohol is not recommended in saunas and rehydration is very important."
"There is also a lot of caution around children in saunas. As a general principle you should be in tune with your body and feel if something feel uncomfortable to you," Cohen said.
When using a sauna it's good to monitor how much you sweat.
"If you're trying to detox it's good to remove the sweat, so don't just let it sit on the skin. Toweling off when you're in the sauna is the best way to do that, and then you can tell how much you have sweated by observing the towel," Cohen said.
Lastly, if you use saunas a fair bit, you might be able to help with some global research.
"I have got a pHD student who is a medical doctor doing research into saunas right now. The research is looking to answer a lot of questions and we're doing that by going to the global community via a survey. We're asking anyone who regularly saunas to help share their experiences," Cohen said.
You can complete the survey through this link.