What about tanning (or tanning studios)? I know there's a big difference between a sauna and a tanning studio, but since we're talking about heating up the body, would it have the same effect? (...despite causing skin cancer)

A sauna does not heat up the body enough to trigger protein denaturation (unless you get locked in and die, which happens to be among my worst nightmares).

Core temperature is tightly regulated, as well. It should be 37degC. Plus or minus just 2 degrees will severely impair function, plus or minus 5 degrees is reason to call 911.

To add to this...

Saunas and ice baths don't damage cells but actually have benefits. Don't quote me as this is a rephrase that makes it sound like bro-science, it actually activate some heat shock proteins and also leads to hormone release.

Better, sound science can be sourced from Dr. Rhonda Patrick a la Tim Ferriss podcast or Google Scholar

Noob question. Is it possible to explain the benefits of sauna with this research?

Our mammalian bodies go to great lengths to keep our cells at a stable temperature to prevent protein denaturation from killing our cells. Our first line of defense for thermostasis is our circulatory system (to carry extra heat energy away from overheated organs towards the surface where it can dissipate), combined with sweating (to allow evaporative phase change to cool the blood near the skin).

One can argue whether sweating in this context does or does not also carry off toxins. But in addition to its thermoregulatory role, increased circulation is one of the body's natural healing mechanisms. (Out of control increased circulation causing tissue damage is one of the reasons we ice injuries.) It delivers oxygen and nutrients to our cells. Increased circulation in the sauna may be giving the body the chance to deliver more of these things and to repair cells and organs at a higher rate than it might otherwise.

I've heard similar things about athletic training while mildly overheated. Training while overheated promotes adaptations to increase the cooling efficiency of your body. These adaptations include increasing heart rate, circulation, blood plasma volume, etc. This, in turn, promotes improvements to endurance, ability to perform in both normal and overheated states, etc.

The body is certainly capable of acclimatizing the high body temps. I don't have the source, but I remember reading that Israeli tank soldiers (who were fighting from inside a tank in the desert) had body temperature of 101 - 102F and were completely fine. At that body temperature most people would start to feel pretty awful.

That's intriguing. Where might one be able to read more about that?

I can't remember what journal I was reading, but I was able to quickly find a fluff article with some decent information [1] that happens to mention an on-point cycling study [2].

For me, this involves training outside in the Texas summer heat (100F+) with plain water. When I race, it is usually earlier in the day (80-90F) and I sometimes use ice socks in my jersey and ice water in my bottles to keep my core temperature down.

[1] http://blog.airiarunning.com/heat-training-does-it-boost-run...

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2963322/

That would corroborate long distance runners from Kenya and Ethiopia.

What doesn't kill you makes you stronger... I guess?

No, or at least definitely not as a blanket statement. There are many kinds of damage where the effect is highly or completely cumulative. In particularly one should be extremely careful of any such claims that involve the nervous system (including the brain) and immune system, neither of which can heal in the same way that many other parts of our body can. With regards to the brain, concussions are a good current example of something showing strong evidence of very dangerous cumulative effects at least somewhat independent of each incidents severity, and with potential for significant delays between events and progression of symptoms. With the immune system a key part of its training and ability to fight off disease could be somewhat summarized as "what doesn't kill you makes you stronger", and we use this with vaccines. Exposure to a varied environment looks to be particularly important as a child. But in some cases later repeated exposure to allergens can result in the development of immune hypersensitivity, which can be deadly serious. The danger can be increased because the sensitization event(s) often does not result in any significant problems itself, rather it is only on exposure following sensitization that the symptoms appear. Of course while these have all been internal systems examples, even exercise can be very dangerous if done inappropriately, without sufficient prep/stretching/maintenance/rest, etc. It's possible someone to hurt themselves in ways that will take a long time to recover from and they certainly won't be stronger at the end of it, rather they'll have to start again from a reduced base.

Ultimately our biological systems are simply too complex to get boiled down to any one universal bit of "common sense". I think it's laudable to try to improve ourselves, and it's true that in some cases that may require challenging oneself and/or cycles damage/repair as in working the muscles, but risks should be appreciated and approached with deliberation too. I'm certainly not trying to rag on you or anything like that, I'm just wary of this sort of thinking without caveat because I've seen it amongst my own circle used to justify some "medicines" and "treatments" and "training programs" that turned out to be quite harmful.

This is increasingly sounding true with research that show periods of starvation are probably beneficial for health. Of course there has been a lot of discussion about fasting, but there is also data that show parental stress during child-bearing probably leads to increased health among progeny.

I'd characterize it as, there are things that can make you stronger that people don't want to do, e.g. fasting, undergoing stress, temperature variation, intensive exercise. There are things that make you stronger that people already like to do (eating food, moving, etc), but we haven't made the effort as a society to automate those things out of our lives.

Are the benefits of sauna even proven? I'm not aware of any studies that show definite benefits, only "may help with" results.

Cell-wide analysis of protein thermal unfolding reveals determinants of thermostability: http://science.sciencemag.org/content/355/6327/eaai7825.long

so how this tie in if at all with the article stating cells can reach 50C in burst while providing energy? https://www.newscientist.com/article/2129849-the-energy-gene...

does this give us the upper limit of the sources we can convert?

I am not a scientist but I think there is a problem in the article that you are correctly (IMO) pointing out. It is that the notion of temperature has not the same meaning at molecular level and at macro level.

Kudos for putting the summary at the very top of the page.

>The proteins that unravel as the temperature starts to rise turn out to be among the most vital.

I also appreciated the dynamic progression indicator at the top of the page. Some of these journal articles are organized and written such that there is no end in sight - it's hard to intuitively know where you are in the article, if you are nearly the buried results/conclusion, etc. The simply indicator tracks progress through the article without having to glance at the oft-invisible right-side scrollbar.

I haven't had that problem as far as I can remember, I rely on the (very thin) scroll bar that's shown on firefox for android.

I'm diverging into off-topic territory now, but I stopped reading the featured article because of the large static header div. Am I in the minority of mobile users who spends all the time in horizontal mode? It seems that probably 50% of mainstream blog or news sites I come across have some sort of obnoxious static header or footer (or worst, both!) that takes up a huge portion of the view when horizontal. Usually useless shit like a link to the main page, or their social media mention count. I take a screenshot of the worst offenders but I haven't posted them anywhere. The absolute criminal in this respect is tech crunch. You MUST orient to portrait and click the expand article button to read anything. Really unprofessional and disappointing, I avoid their links if I catch it in time.

Sorry, rant over.

Similarly, PDFs of articles in the PeerJ family of journals (e.g. [1]) have a progress bar symbol at the bottom-right of each page, which is also a nice feature.

[1]: https://peerj.com/articles/cs-103.pdf