Now that winter has hit the northern hemisphere, our thoughts often focus on ways to keep warm. Well, not only can a nice, sweaty sauna do the trick, but according to a recent study repeated saunas may just help fend off dementia — at least for middle-aged men.
Dr. Tanjaniina Laukkanen from the University of Eastern Finland and colleagues followed the health of over 2300 middle-aged men (42-60 years old at baseline) for over 20 years. They analyzed possible associations between the frequency with which the men used saunas and the risk of their developing Alzheimer's disease or other types of dementia.
Sauna is a Finnish word that refers to a small room or building used for dry or wet heat exposures. Its basic function is providing a place to perspire. Saunas have been linked to a variety of positive health effects, ranging from temporary relief of the common cold, to reducing symptoms of COPD, rheumatoid arthritis, and chronic fatigue syndrome. Although we tend to associate saunas with the Scandinavian countries, people from many cultures use such repeated heat exposures — Thailand, Russia, and Ireland are just a few.
The authors of the Finnish study referenced above noted that sauna bathing is associated with better hemodynamics, induced fluid loss and and possibly with a better cardiovascular and circulatory function, such as lower blood pressure. This suggested to them that there might also be an effect on brain function, which was the purpose of their investigation.
The men whose data was analyzed were part of the Kuopio Ischaemic Heart Disease study, who began the study between 1984 and 1989. In their analyses, the investigators controlled for numerous possibly confounding factors, such as smoking status, previous heart attacks, LDL cholesterol levels, body mass index, Type 2 Diabetes, and age. The participants were monitored annually for new cases of dementia of any type.
Men were divided into 3 groups: Those who used saunas once per week, those who used them 2-3 times per week, and those whose exposure was 4-7 sessions per week. They found that compared to once per week sauna bathers, those whose exposure was 4-7 times per week had a 65 percent lower risk of Alzheimer's disease and a 66 percent lower risk of all types of dementia. These differences were statistically significant.
The authors noted that there are limitations to the generalized results, since their study was limited to middle-aged Finnish men. Also, their sauna temperatures averaged 80oC (176oF), which might be different from those used in other places. Further, of course, it would important to know whether the same outcome would be seen in women and men of other ethnic groups or of different ages. And of course, these associations between risk of dementia and saunas are not causal — one can't tell which way causality might go, or if indeed some other underlying factor was responsible for the link.
However, if a sauna sounds like a good way to warm up, go for it — just remember to stay hydrated and avoid alcohol. And maybe — just maybe — frequent sauna use will help keep your mind clearer as you age.