Scientific Nutrition Update 34: Sauna’s

Inspired by some of the profiles in Tim Ferriss’ book The Tool’s of Titans who used saunas to improve athletic performance I looked at what the literature suggested and found that this is a pretty well supported tactic.

Script (remember I ad-lib a lot):

For today’s episode I am going to talk about something I have come across a couple of times in Tim Ferriss’ writings and that was the idea that there are likely health benefits to saunas.  I wanted to go through the literature and see what evidence existed around this. Turns out there is some really interesting evidence, especially for athletic performance. Now before I continue I need to again remind you that I am not a doctor, nothing contained in here should be construed as medical or training advice, and that it is purely informational.  People have died in saunas, be smart people. Talk to the actual professionals guys, I’m a college kid with a laptop.


There are a variety of elite level athletes who have used both hot and cold exposure for reasons like recovery, and in attempts to increase growth hormone levels and improve endurance.  The idea of this was fascinating to me because it madea kind of intuitive sense. I know how important it is for the human body to maintain homeostasis, and so it would make sense that we would see changes in certain hormone levels as a result of extreme temperatures, though I did wonder whether that change would translate into measurable gains.


There was a really interesting study done that looked at changes in hormone levels in 55 healthy volunteers in a finnish sauna and they found that serum growth hormone levels were increased by 142% of baseline, suggesting that there was a significant increase in growth hormone levels.  These levels however did return to baseline within an hour, suggesting to me that the primary utility here may be immediately before, or more likely after exercise, and that the primary benefit is likely going to be for athletes at a high level who are working to eke out incrementally higher gains.  What I mean is that for the normal untrained or somewhat active person, the extra effort is likely not worth the gain, because there are likely easier leverage points to focus on. However, for an elite diet who has already dialed in their diet, sleep, training, and everything else the gain may be worth it.


I was also curious about the claim that sauna’s could help with endurance and so I went through the literature and there was an interesting study done on 6 trained men that showed that when they used the sauna after their training their run time to exhaustion was increased by about 30%.  The author’s claimed this worked out to about a 2% improvement in an endurance time trial, so we are again seeing that for high level athletes this could be a useful technique. However, we need to be careful with this study because it is so small, it is such a narrow group, and there is no way to really blind treatment with a sauna.  As such we need to be careful to not overinterpret this study.


There does seem to be some importance to the exposure coming afterwards.  There was a study done on ten healthy weight trained men, which again is small and hard to generalize, that looked at muscular strength, endurance, and power after exposure to either normal room temperature air or a sauna.  What they found was even maintaining hydration endurance was decreased, bench press stayed the same, leg press decreased, but muscular power measured with the vertical jump actually significantly increased. What this suggests to me is that if I was going to offer advice I would say it is most likely most beneficial to use the sauna after the exercise and not before.


There was another study that actually compared infrared saunas to traditional Finnish saunas and found that both significantly increased growth hormone levels, though I went digging through the data and found something really interesting.  Namely both increased, but the traditional increased it by vastly more than the infrared one, I don’t know why this is and it is actually not statistically significantly different because there is a massive margin of error on that value. Like the margin of error is larger than the actual value which suggests to me there’s some outliers screwing it up, but still potentially interesting.  Regardless both forms of sauna showed an improved recovery in jump ability compared to no sauna which is promising.


Overall, I think many of the people profiled in Tim Ferriss’ work may be on to something here.  Especially for high level athletes saunas seem like they could be a useful tool that can help with a bit of incremental improvement.  

Bibliography (I may not directly address these studies in the episode but I looked at them and thought they might be valuable):

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