Saunas can reduce stroke risk -- more evidence that there could be a 3rd pillar of physical fitness beyond diet and exercise

  • Regularly taking saunas is associated with a more than 60% reduction in stroke risk, according to a new study.
  • This adds to a growing body of research that suggests exposure to different temperatures – both hot and cold – can provide health benefits.
  • A fitness approach known as environmental conditioning centres on the idea that climate-controlled bubbles aren’t always good for our health.

In the modern world we spend a lot of time in climate-controlled spaces with air-conditioning or heat. The temperature around us rarely dips below 68 or creeps above 72 Fahrenheit.

And there’s more and more evidence that this may not always be good for us.

In a study recently published in the journal Neurology, researchers found that regularly taking saunas was associated with a substantially lower risk for stroke among middle-aged and elderly men and women. Other research has found that saunas and hot baths are also connected to positive health effects, including reduced inflammation, improved blood sugar, and lower blood pressure.

Still other studies have shown that exposure to extreme cold can help people burn fat, improve the immune system, and counteract some effects of type 2 diabetes. Those findings have led some people – notably athletes and Silicon Valley biohackers – to incorporate cold showers and ice baths into their routines.

The practice of seeking out health benefits by forcing your body to cope with hot and cold temperatures is known as “environmental conditioning” among fitness experts.

‘What Doesn’t Kill Us’

Dutch fitness guru Wim Hof, who goes by the nickname “Iceman,” is credited with popularising one branch of environmental-conditioning practice.

Hof argues that our circulatory systems are designed to help us adapt to different surrounding conditions. He says that a lack of stress on this system, which comes from always controlling the temperature around us, could be partially responsible for diseases of the circulatory system like hypertension and stroke.

Journalist and anthropologist Scott Carney investigated Hof’s method in his book,”What Doesn’t Kill Us: How Freezing Water, Extreme Altitude, and Environmental Conditioning Will Renew Our Lost Evolutionary Strength.” In it, Carney suggests Hof’s concept of environmental stress could be considered a third pillar of physical fitness, alongside diet and exercise.

In Finland, where the latest study on saunas was conducted, environmental conditioning has long been in practice. There, taking a sauna as a means of making the body more resilient is known as “hardening.”

Ice bathChristopher Lee/Getty Images

Studying saunas in Finland

In the latest study, researchers looked 1,628 men and women in Finland between the ages of 53 and 74. They followed that group for an average of almost 15 years, tracking the participants’ cardiovascular health and stroke incidence.

Most Finns take a sauna at least once a week, according to an editorial published alongside the study. So participants were divided into three groups: one of people who took saunas once weekly, the second of people who took two or three saunas, and the third of people who took an impressive four to seven saunas a week.

That last group, with the highest sauna frequency, had more than a 60% reduced risk of stroke compared to the once-per-week group. The middle group had a 12% lower risk of stroke than the low-frequency group.

This is an observational study, so it can’t prove that saunas directly caused the lower stroke frequency. But it’s not the only study showing health benefits associated with heat. Other researchers have used data from the same study to calculate that people who take saunas more frequently have lower risk for high blood pressure and lung disease. Other studies show reduced risk for heart attacks with more saunas.

Studies have also shown that regular hot baths can improve blood pressure and may cause blood-sugar improvements and an anti-inflammatory response similar to exercise.

The benefits of exposing your body to cold

On the other side, a recent study published in the Nature journal Scientific Reports found evidence that exposure to cold temperatures could transform the type of fat we form in our bodies to a healthier kind of fat, helping us burn off excess body weight.

Other data indicates that Hof’s cold exposure method – and an accompanying breathing regimen he teaches – can lead to better fat-burning capabilities, weight loss, improved immune-system function, and the ability to counteract some effects of type 2 diabetes in certain people.

For those interested in incorporating some of this science into their lives, hot baths and saunas might be easier to add into a fitness regimen than cold showers or ice baths. But perhaps the biggest takeaway might be that a little bit of environmental stress – allowing yourself to feel hot or cold and adapt to that – might be healthier than closely controlling the temperature around you at all times.

There are likely good reasons why many cultures around the world have sought out extreme temperatures for health for hundreds of years.

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