Actually, the rate of blood filtration by kidney glomerulae is pretty constant and independent of the amount of urine in your bladder. Except if you overflow to the point of drowning your kidney of course.
This is simply laughable and very easily checked out. Here is one random study:
https://link.springer.com/article/10.1007/s00244-010-9611-5
> Many toxic elements appeared to be preferentially excreted through sweat
Here is another quick one
https://onlinelibrary.wiley.com/doi/full/10.1155/2012/184745
> Sweating deserves consideration for toxic element detoxification.
Its even observable directly - just go next to the heavy smoker during exercise.
While it might be less than dedicated organs, the skin is the largest organ by far.
Ofc, the topic is debated like every single thing in medicine, but calling it a myth is nonsence.
This review from 2019 states:
> However, the effectiveness of sweat glands as an excretory organ for homeostatic purposes is currently unclear as there are no comprehensive reviews on this topic.
https://www.tandfonline.com/doi/full/10.1080/23328940.2019.1...
It also mentions stuff similar to the things you wrote:
> The role of sweating to eliminate waste products and toxicants seems to be minor compared with other avenues of excretion via the kidneys and gastrointestinal tract; as eccrine glands do not adapt to increase excretion rates either via concentrating sweat or increasing overall sweating rate. Studies suggesting a larger role of sweat glands in clearing waste products or toxicants from the body may be an artifact of methodological issues rather than evidence for selective transport.
However, the problem here is that normal sweating is taken into account, but discussion here is about sauna/exercise in which case sweating waste products approach kidney flux rates (which is why people do those things to detoxify) - human can easily sweat 1.5L per hour in that case, which is comparable to daily pee volume, and there are measurements regarding sweat composition that show comparable waste excretion:
| Substance | Sweat (1h) | Urine (24h) |
| --------- | ---------- | ----------- |
| Urea | ~0.3–1.2 g | ~20–30 g |
| Lead | ~5–50 µg | ~10–50 µg |
| Arsenic | ~10–60 µg | ~20–200 µg |
So, I wouldn't dismiss based on current knowledge, and besides, this has no practical importance even if so, as sauna has the number of other measurable benefits.Otherwise, I agree with you regarding focus - liver should be treated as sanctuary.
That false statement really makes me unsure about the quality of the article. And I'm saying this as someone who uses sauna daily, when possible (I have one at home, and I grew up with saunas).
"De-toxification" by sweating is a myth. Sweat glands are very simple organs (think salt on one side, which results in pressure, i.e. osmosis) and can't do anything of the sort. You'll be much better off peeing.
Saunas probably have good health effects. I'm certainly happy as a sauna user. But there's no de-toxification in this.