Saunas are an odd phenomenon: Hot, dry and often populated with mostly-naked people, their chief benefit appears to be sweating out a hangover. Now, a new study from Finnish researchers finds that spending time in a sauna may come with a decreased risk of heart disease – for men, at least.
Indeed, they found that men who logged seven weekly sauna sessions were less likely to die at all, much less of a heart attack.
“There was an inverse relationship between sauna and (cardiovascular disease) risk, meaning that more is better,” Dr. Jari Laukkanen, a cardiologist at the Institute of Public Health and Clinical Nutrition of the University of Eastern Finland in Kuopio, told Reuters Health by email. “On the basis of these results, it seems that more than four sauna sessions per week had the lowest risk, but also those with two to three sauna sessions may get some benefits.”
Beginning in the 1980s, the study followed 2,000 Finnish men and asked them questions about their weekly sauna use. 1,500 reported using a sauna two to three times per week; 600 visited once and 200 visited four to seven days per week. Duration was broad, ranging from two to 90 minutes per session at temperatures between 104 and 212 degrees Fahrenheit.
By 2011, a variety of hospital reports and death certificates revealed that 190 men had died of sudden cardiac death, 281 died of coronary heart disease, 407 from cardiovascular disease, and 929 had died from other causes.
What they found was an undeniable correlation between sauna use (or the lack thereof) and cardiac death: 10% of once-per-week visitors suffered cardiac death versus 5% of those who visited between four and seven times per week.
Other heart issues showed a similar correlation, as well as death from any cause: The least frequent visitors demonstrated a 49% risk of death, versus 31% for the most ardent sauna users.
Though the authors believe they were fastidious in controlling for other mitigating factors, the study can only prove correlation, not causality. It’s still possible that the kind of people who visit a sauna seven days per week are also more health-conscious, carefully monitoring their diet and exercise as well.
If the sauna itself is a source of health benefits, the researchers speculate that they may have to do with the physiological effects of heat. It may improve circulation, which has been associated with a lower risk of heart disease. It’s also just flat-out relaxing, the researchers note, as there’s not much else to do in a sauna besides sit.
They suspect women would show a very similar pattern of risk, but cannot say for sure until such a study has been conducted.