Based on a talk given at the Sauna Congress in 2006 by Docent Markku Partinen from the Rinnekoti foundation’s Skogby Sleep Clinic.
We know that the sauna relaxes the body and mind, inducing pleasant and calm feelings. In addition to that, studies have shown that the sauna has a positive impact on our sleep as well. Sauna bathing increases the amount of deep sleep we get, and sufficiently deep sleep, in turn, affects our memory functions, learning and problem solving skills in a positive way. Through good sleep, bathing in the sauna promotes our ability to think and, subsequently, our ability to make important decisions.
The sauna’s effects on sleep
So far, the only study investigating the effects of sauna bathing on our sleep patterns is the one published by Putkonen and Elomaa (1976). By monitoring five test subjects’ sleep patterns after a sauna bathing session and again after no time spent in the sauna, they concluded that the former increased the amount of deep sleep statistically significantly. During the first two hours, the amount of deep sleep increased by over 70%, while during the first six hours the figure was 45%. The amount of time spent awake after the sauna reduced statistically significantly.
Some of the positive effects of sauna bathing on the test subjects’ ability to fall asleep and have good-quality sleep may be explained by the changes in temperature. An increase in our internal temperature makes us fall asleep quicker and results in more deep sleep.
Deep sleep increases
Putkonen and Elomaa also looked at the effects of the temperature changes. The test subjects’ internal body temperature rose significantly during the roughly 30 minutes spent in the sauna. Afterwards, the temperature decreased again and the brain cooled down, and around two hours after the sauna the test subjects began feeling tired. The amount of deep sleep also increased (Putkonen and Elomaa, 1976).
Research on the effects of skin temperature changes has had similar findings. By warming up the skin on our hands and feet, we can improve our ability to fall asleep and the quality of our sleep. The impact of sauna bathing on the ability to fall asleep and the sleep patterns is, for the most part, likely caused by changes in the neurotransmitters of the brain.
The most important neurotransmitter in terms of falling asleep is serotonin, but noradrenalin plays a vital role in our sleep patterns as well. An increase in body temperature also increases the serotonin metabolism and has an effect on noradrenalin too. It causes the amount of noradrenalin in the brain to reduce, which is linked to a lowered level of alertness and an increased amount of deep sleep. It is currently believed that these effects are mainly explained by the temperature changes, although the exact mechanism behind it is still poorly understood.
The first written material on the effects of the sauna on our sleep date back to 1765. In it, Martin states that the sauna can often improve the quality of our sleep, although in some cases it has the opposite effect. These effects were later also studied amongst young Finnish men in connection to interrupted sleep and sleep habits (Partinen, 1982).
Falling asleep becomes easier
Most test subjects found it easier to fall asleep after a bathing session in the sauna, with only around three per cent experiencing increased difficulties. Furthermore, one third of the respondents felt that the sauna had no effect on how quickly they were able to fall asleep. Over 40% found the sauna to have a positive impact on their sleep quality, although the majority (approx. 60%) said that they had not experienced a significant impact. Only two per cent of the respondents stated that they tend to sleep worse after the sauna. The reason for this is unclear, but it may be connected to migraines.
Bathing in the sauna makes falling asleep easier and usually improves the quality of sleep. As a result, it also allows us to think more clearly and make important decisions.
The information on the page was compiled by Raili Vihavainen.