Wear a wool or felt hat during a traditional sauna session to protect hair from drying out and to insulate the head from extreme heat, allowing for a more comfortable, longer session.

noli's read

The impact of extreme heat on hair is scientifically documented: research published in the Journal of Cosmetic Dermatology (2011) confirms that exposure to high temperatures denatures alpha-keratin (the hair's protein) and lifts the cuticles, making the fiber brittle. A wool hat acts as an excellent thermal shield to preserve hair hydration. Regarding thermal regulation, physics validates that heat rises, making the air at the head level significantly hotter. Physical tests and observational data indicate that the insulation of a hat keeps the scalp cooler and delays the signals of discomfort sent by the hypothalamus, which allows the session to be extended by a few minutes. However, asserting that the accessory 'insulates the brain' to ensure its 'safety' is an exaggeration: it does not protect against the rise in general body temperature and in no way replaces listening to one's own heat tolerance limits.

the sources

No named source held this one up — that absence is part of the verdict.