It’s the hottest trend in health and fitness: 95°C! Sauna, an ancient Finnish tradition of rest, relaxation and perspiration – and public nudity, if that’s your jam – is suddenly the wellness hack to rule them all, credited with a voileipäpöytä (Finnish for smörgåsbord) of benefits: lowering blood pressure, reducing inflammation, burning calories, improving mood, promoting sleep and aiding recovery from injury. Sauna has been promoted as a treatment for heart disease,…

