The topmost comment in this comment thread starts with the fact that there are over a thousand studies on this already, no? Even if the whole effect isn't well understood, it seems like there is some science behind this.

One could argue that the research goes all the way back to Dr Frederick Cook aboard the Belgica during an Antarctic expedition I which they became trapped by the sea ice. The men suffered from multiple maladies, scurvy included, with one of the prescribed treatments being to stand nude near a blazing fire for an hour. If his notes are to be believed, the men saw some immediate changed in their overall health beyond simply getting warm. By some accounts, he became a bit of a fanatic about how much we humans need the sun, after that.

Or it could be vitamin D, or sunlight killing ticks, or fungal pathogens, or it could be the release of endorphins due to mild sun burn, or any number of other things.

I'd say it's all those things, likely in different combinations based on the circumstances. Cook's notes indicate that he may have considered it a panacea of sorts, triggering a bunch of different stuff that helped overall health, but keep in mind this was something to tune of 150 years ago, so the information he was working with may have limited the scope of his understanding. For all his otherwise infamous reputation, his work aboard the Belgica was nothing short of pioneering for the time. His life after that expedition over-shadows any positive contributions to science he made, unfortunately.

As placebos go, feeling toasty warm has to be way up there.

Vitamin D is not an outcome of standing by fire. It is from UV spectrum which is entirely absent from fires. It needs high temperature fire like fusion to be emitted. Totally doable by sun but not by your campfire.

There maybe a thousand studies.

How many well-designed double-blind studies in humans? That’s the question

I'm no expert but my gist is that light interacts with an enzyme in the electron transport chain (cytochrome c oxidase). CCO is embedded in the inner membrane of mitochondria, and nitric oxide binds to CCO which temporarily inhibits cellular respiration as a natural metabolic regulation to control oxidative stress. Red and NIR light can photodissociate NO from CCO with the right intensity and wavelength, which restarts cellular respiration and ATP production. The release of NO into the bloodstream can secondarily trigger other chemical pathways involved in vasodilation and reactive oxygen species management.

Edit: found a wiki with more details:

https://en.wikipedia.org/wiki/Light-emitting_diode_therapy#P...

In general, with a very few exceptions, if the body has a regulatory mechanism there's at least some reason for it, and tinkering with it without understanding it can have unpredictable downsides.

>as a natural metabolic regulation to control oxidative stress

That sounds like something I'd be very wary of manipulating without a good deal of clinical trials. Isn't oxidative stress one of like three primary hypothesized mechanisms of aging?

The body has regulatory mechanisms formed 100k to 1000k years ago, and some even older. The life was a bit different then, as was humans' mental capacity and knowledge.

This is why humans have to actively overcome and sometimes subvert various mechanisms that presume the need to conserve the energy: they hit a gym which the body doesn't like, they limit sugars and fats which the body craves, they consume caffeine, nicotine, or even cocaine to trick the body into working harder and complaining less.

Compared to that, hitting the body with some NIR radiation seems very benign. You can get a lot of that just by walking in the sun, and there are no known adverse effects of that, unlike, say the use of the chemical substances. If anything, it's a promising field of research.

>You can get a lot of that just by walking in the sun, and there are no known adverse effects of that

Other than sunburn and skin cancer?

Sunburns and skin cancer are induced by UV, not NIR light. Put on the protective cream.

Morning and evening is entirely infrared (80-90 percent with rest of it visible). No UV.

i dont know what you mean by science. There are literally 1000s of research papers showing mitochondrial "horsepower" with red light on every type of tissue. Cells heal themselves as first thing when they get extra energy. Do you want your neighborhood clinic to validate before trying some light samples out?