I AM NOT A DOCTOR. PEOPLE HAVE DIED IN SAUNAS. THIS IS INFORMATIONAL ONLY. ALWAYS CONSULT WITH A MEDICAL PROFESSIONAL.
Occasionally I’ll come across a piece of health or fitness advice that sets my bullshit detector off hard. I was reading Tools of Titans by Tim Ferriss (a book I highly recommend) when a couple of the people profiled in the book suggested that one of their secrets to health was using a sauna.
One of the first people profiled was Amelia Boone, who is a well known obstacle course racer, and she claimed that using the sauna increased her endurance. One anecdotal piece of evidence obviously wasn’t enough for me, and I needed some more substantive support for it, (especially if I wanted to keep calling this Scientific Nutrition). However, the anecdotal evidence was intriguing considering this has become a somewhat common practice, and has been used by other elite athletes including David Zabriskie a Seven-time US National Time Championship winner. This was still not convincing to me so I marked it as something needing more research and read on, the very next profile started flirting with more of the evidence I needed to be convinced.
Dr. Rhonda Perciavalle Patrick Ph. D was the next profile and she is a premier researcher into again at the Salk Institute for Biological Studies, and was one of the researchers who has elucidated a mechanism by which Vitamin D can influence serotonin levels. She is very obviously a respected scientist who was likely to trust scientific evidence to form her opinions. In her profile she claimed that hyperthermic conditioning (that’s the sauna) can increase growth hormone levels, improve endurance, and seems to reduce muscle soreness. Specifically she claims a study found that a 30-minute sauna session twice a week for 3 weeks post workout increased the time to reach exhaustion by 32%. she also claimed two 20-minute sauna sessions separated by a 30-minute cooling period elevated growth hormone levels two-fold over baseline, and a hotter dry sauna five fold!
These were obviously intriguing claims so I decided to see if there was validity to them. The first study she referenced does seem to backup her first claim. However, there are several things that do need to be made clear before we attribute too much stock to this claim. The study was done with only six men, and it was trained individuals. This is not an easy group to generalize from, but it does lend some credence to the anecdotal reports previously detailed.
Her second claim also seemed to have interesting validity. Though perhaps not to the degree quoted as there is some disagreement in the literature. She cited a two-fold increase in growth hormone however, an older study found closer to a 1.5 fold increase. However, that is still a significant change. This does seem to suggest that heat exposure may have an increase in growth hormone, which suggests that it could improve performance for both endurance and strength athletes.