Longevity and Health Benefits of Saunas

Two women in the sauna

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While sitting in a sauna might feel peaceful and relaxing, is that steamy or dry heat actually healthy? "Sweating out toxins" seems like pop science, and doesn't the risk of overheating and dehydration cancel out any physical or meditative benefits?

Turns out, you don't need to worry. A 2015 study of older Finnish men found that the risk of cardiovascular death and mortality from any cause was significantly lower among those subjects who regularly spent time in a hot sauna. What's more, the risk of death was further decreased with longer sauna sessions.

Sauna Habits in Finland

Published in the Journal of the American Medical Association (JAMA) Internal Medicine, the study describes typical sauna use by Finnish adults: a weekly session in a dry, hot sauna room with a temperature between 77°C-80°C (170°F-176°F). While water is occasionally thrown on the hot rocks to generate steam, the room is typically not humid.

Who Was Studied

A group of 2,315 middle-aged men from eastern Finland was questioned about lifestyle habits such as smoking, physical activity, medications used, and illnesses — along with sauna use — and their blood pressure, cholesterol, and other heart disease risk factors (such as body mass index or BMI) were measured. All part of the Finnish Kuopio Ischemic Heart Disease Risk Factor Study, the men were between the age of 42 and 60 years at the study's start, with an average age of 53 years. On average, the men would be classified as overweight, with a BMI of 26.9. First measurements took place in the 1980s, and the men were then tracked over a follow-up period of about 21 years.

The men were divided into different groups according to how often they used a sauna: one time, 2-3 times, or 4-7 times per week. They were also sorted according to the duration of their typical sauna "bathing" session: fewer than 11 minutes, 11-19 minutes, and longer than 19 minutes.

The Sauna and Heart Health Connection

After an average of two decades, the health status of the men was retrieved using medical records. By the end of the study, about 40% of the participants (929 of the original 2,315) had died, 95% (878) of those from cardiac events. The researchers discovered that the higher the frequency of sauna bathing, the lower the risk of sudden cardiac death, fatal cardiovascular disease, and all-cause mortality (that is, death from any cause). When compared with having only one sauna session in a week, the men were 31% less likely to die of any cause with 2-3 sessions, and 39% less likely to die of any cause with 4-7 weekly sauna sessions.

Duration made a positive difference too. Compared with having short sessions (less than 11 minutes), men who spent between 11 and 19 minutes in the sauna had a 7% lower risk of sudden cardiac death. For those with even longer saunas — 19 minutes or more — the risk of sudden cardiac death was found to be much lower (52% lower risk) compared with men having only short sessions.

Why Would the Sauna Be Heart-Healthy?

The researchers, from the University of Eastern Finland, Emory University and elsewhere, point to previous studies suggesting that the heart rate increase triggered in a hot sauna may mimic the cardiovascular benefits of physical exercise, such as lowering of blood pressure and improved cardiac output. The scientists also cite older evidence that sauna use improves lung capacity.

Risks of Spending Time in the Sauna

While the initial intake assessments of these men included several objective measurements like blood pressure and blood sample analysis, the researchers did not get updated information about the subjects' ongoing sauna habits during the 20-year follow up, and could not verify if the initial habit continued uniformly during that time period.

In addition, the men were gathered from a community accustomed to regular dry sauna use, and the scientists caution that steam rooms, hot tubs, and saunas set to lower temperatures may not offer the same apparent benefits. People with low blood pressure should be aware that a decrease in blood pressure typically occurs immediately after a sauna session. Finally, alcohol use has been linked to sudden death within 24 hours of using a sauna.

The authors also suggest future investigation of the risks or benefits of sauna use for older women, along with research into the source of the positive heart changes in a sauna setting.

Bottom Line

If sitting in a hot environment for any length of time makes you uncomfortable, skip the sauna. If, on the other hand, you find peace and relaxation within those wooden walls, enjoy the mindfulness and potential heart benefits they may offer.

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Article Sources

  • Tanjanlina Laukkanen, Hassan Khan, Francesco Zaccardi, Jari A Laukkanen. "Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events." Jama Intern Med Published online February 16, 2015. doi:10.1001/jamainternmed.2014.8187.