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.
Triglycerides drop measurably after repeated WBC sessions, and LDL and total cholesterol also appear to decrease. That is the finding of a summary of seven studies. But the researchers themselves caution: the studies were small and the treatments differed so greatly from one another that you cannot simply add up the results. People with a lower BMI seemed to show greater changes in total cholesterol and LDL. These are therefore preliminary signals, not firm conclusions.
For athletes who want to recover quickly after training or competition, WBC falls short. Cold-water immersion does show better results in that context. WBC adds little for athletic recovery on this point.
Following knee surgery (ACL reconstruction), there is some evidence that cryotherapy reduces pain and lowers the use of painkillers. The certainty of that evidence is, however, low. In broader orthopaedic practice, for conditions such as osteoarthritis or fibromyalgia, outcomes are mixed and weakly supported. Side effects have also been reported: frostbite of the skin and temporarily reduced muscle strength.
In a small study of patients with Chronic Fatigue Syndrome, improvements in fatigue and concentration were largely maintained in the 22 patients assessed four weeks after the end of treatment. At the same time, so many participants dropped out that the results must be interpreted with caution.
A practical obstacle in all WBC research: treatments vary enormously between studies in temperature, duration and number of sessions. This makes it difficult to compare results or to know which protocol you need. Finally, the well-established cooling of newborns after oxygen deprivation to the brain is an entirely different matter from commercial WBC. The two should not be lumped together.
Sources: multiple small RCTs and observational studies, one meta-analysis of 7 studies (lipid effect), one study in 22 CFS patients. Strong evidence (large RCT) exists only for medical neonatal hypothermia, not for commercial WBC.
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.
How healthy is meditation, and what does it actually do for you?
Meditation has a moderate but well-demonstrated effect on depression, anxiety and pain, and can safely be combined with other treatments. For other health claims the evidence is still too thin to rely on.
Is donating blood regularly good for your health?
Regular blood donation is safe for many people, but it can deplete your iron stores, especially if you menstruate or donate frequently. Have your ferritin level checked regularly and discuss your donation frequency with your doctor if you want to become pregnant or are feeling tired.
Does stem cell therapy work against ageing in humans?
For one specific application, physical frailty in older adults, there is a first randomised trial with a positive result; for all other ageing-related applications it is too early for firm statements, and stem cell therapy cannot yet be considered a proven anti-ageing treatment.
Does earthing (grounding) actually work for your health?
There are preliminary indications that earthing may improve pain, fatigue and sleep, but the studies are still too small and insufficiently independent to support firm conclusions. Walking barefoot outdoors carries no known risks, so trying it is perfectly fine; but do not expect a proven miracle cure.
Is curcumin well absorbed by your body?
Ordinary curcumin without any addition is barely absorbed by the body; choose a product with piperine (black pepper extract) or a specialised formulation to notice any effect.