Does the sauna help with weight loss?
The sauna makes you sweat, not slim: the weight loss is temporary fluid loss that disappears as soon as you drink again. If you want to lose weight, exercise and eating less is the way; the sauna is perfectly fine to use alongside that, but do not count on it as a slimming aid.
Two short sauna sessions, or four sessions of ten minutes each, can leave you roughly half to three-quarters of a kilogram lighter immediately afterwards. That sounds appealing, but it is purely fluid loss: as soon as you drink again, the weight is simply back. No actual fat burning takes place in the sauna itself.
People who are overweight lose slightly more fluid per session than people of a healthy weight. That may sound like an advantage, but it is more of a warning: they also face a greater risk of dehydration, and their heart and blood pressure respond less favourably to the heat load. Anyone who is overweight and steps into the sauna to lose weight is therefore not doing so without risk.
Wearing a sauna suit during intensive interval training does raise energy expenditure slightly, but the difference amounts to an average of just 23 kilocalories per session. Fat burning in the hour afterwards was marginally higher, but the researchers themselves concluded that the difference is too small to contribute meaningfully to weight loss.
What the sauna genuinely can do has little to do with slimming. Regular heat exposure improves endurance in trained athletes, presumably because blood volume increases. Note the flip side, however: fluid loss caused by the sauna impairs your endurance even at a loss of less than 2% of your body weight. Anyone who uses the sauna to lose weight and then finds their athletic performance has suffered has gained nothing on balance.
This answer draws on two small studies into the weight effects of sauna use, one study on the sauna suit during interval training, a review article on the consequences of fluid loss for athletic performance, and a randomised study on heat acclimatisation in cyclists. The evidence on temporary weight loss and safety risks is fairly consistent; the evidence on the sauna suit is thin and the researchers themselves qualify the effect as too small. No studies were included that have examined long-term body composition or fat loss from sauna use.
Can heat, such as a sauna, damage your cells or actually make them stronger?
Moderate heat briefly damages cells, but simultaneously triggers a repair response that makes the cell more resilient. Repeated sauna use appears beneficial for inflammation levels, immune function, and possibly blood sugar as well, but large randomised studies are still lacking.
Does cold water swimming improve healthy aging?
For most healthy people, occasional cold water swimming is probably safe. Do you have cardiovascular disease or high blood pressure? Discuss it with your doctor first, because the blood pressure effects are considerable.
What are the health benefits of forest bathing?
Walking in the forest regularly measurably reduces anxiety, low mood, and stress. There are positive signals for blood pressure and the immune system, though the evidence there is less clear-cut.
Does extra salt help with fatigue during fasting?
Baking soda (sodium bicarbonate) reduced fatigue in trained men who had fasted and then exercised, but this was found in only one small study and says nothing about everyday fasting-related fatigue. Ordinary table salt has not been studied for this purpose.
Does whole-body cryotherapy actually work for your health?
For specific applications, such as pain following knee surgery and possibly improved lipid levels, WBC shows small positive signals, but the evidence is too thin and too inconsistent to recommend it broadly. If you still want to try it, be aware that side effects such as skin frostbite are possible and that no standard protocol exists.
Do you lose muscle mass when losing weight with a GLP-1 medication?
With GLP-1 medications you do indeed lose muscle mass alongside fat, but you can largely limit this by combining resistance training with adequate protein intake. If you are older or already frail, discuss this risk explicitly with your doctor before starting.