Heat as Medicine: The Sauna

Regular sauna bathing is one of the best-studied traditional health practices. In a 20-year Finnish study of more than 2,300 men, those who used a sauna 4–7 times a week had markedly lower rates of fatal heart disease than those who went once a week (Laukkanen et al., JAMA Internal Medicine, 2015). Sweating is also one route by which the body excretes some environmental chemicals (Genuis et al., research on sweat analysis).

One person's self-tracking report shared in Raven's notes found big drops in measured plastics-related chemicals after a course of sauna sessions — and also a temporary drop in sperm quality, a known effect of heat on male fertility.