Cold-water immersion for health outcomes: a systematic review

Researchers combined the results of 11 studies involving 3,177 mostly healthy adults. The studies looked at cold showers, ice baths, and cold-water swimming. They measured stress, mood, sleep, quality of life, and immune changes, rather than lifespan. Cold-water immersion was linked with less stress 12 hours later, but not immediately or at most other times. It did not clearly improve mood or immunity. Sleep and quality of life improved in some studies, but these findings came from very limited evidence, and inflammation, the body’s short-term stress response, rose right after immersion in one study.

What this means for you: This review does not provide a strong reason to buy cold-plunge equipment for general health or longevity. Cold water may help some people feel less stressed or sleep better, but the benefits are uncertain and short-term discomfort or risks remain.