The practice of cold immersion, once reserved for elite athletes, has now spread to regular gyms, recovery studios, and wellness centers in Cape Town, where it is promoted as a method for 'nervous system regulation.'
National Geographic's Stance
National Geographic has raised critical questions regarding the popularity of ice baths, wondering whether such exposure truly contributes to weight loss, enhanced mental acuity, and faster post-workout recovery. According to research findings, many of the claimed benefits are not substantiated.
Meta-Analysis Results
A systematic review and meta-analysis published in the journal Medicine in 2026 analyzed 13 randomized controlled trials involving 214 physically active individuals. It was found that immersion in cold water was more effective than whole-body cryotherapy in alleviating delayed onset muscle soreness within 24 hours, although the statistical significance of this effect disappeared after 48 hours.
Regarding performance, the review authors were more cautious. Whole-body cryotherapy showed a small and inconsistent short-term boost to jumping performance after 24 hours, but no difference between the two methods was observed after 48 hours. Researchers also noted high heterogeneity in the analysis of jumping performance, which requires caution when making such claims.
Cold Water's Effect on the Body
Another systematic review and meta-analysis, published in PLoS One in 2025, examined 11 studies involving 3177 healthy adults who were exposed to cold showers, ice baths, or immersions at temperatures ranging from 7°C to 15°C for periods from 30 seconds to two hours. The review showed an acute inflammatory response immediately after immersion and one hour later. Stress levels decreased after 12 hours, but no immediate, hourly, 24-hour, or 48-hour reduction was observed.
Furthermore, this study did not reveal any significant immediate or hourly impact on immune function. However, the same work noted positive aspects: improved sleep quality and quality of life, as well as a trend toward a 29% reduction in absenteeism among participants who took cold showers. Nevertheless, the evidence base was limited by a small number of randomized trials, small sample sizes, and insufficient population diversity in the studies.
Physiology and Risks
In a narrative review published in the International Journal of Biometeorology in 2025, possible mechanisms of hydrotherapy through thermogenesis and brown fat—a type of fat tissue that burns energy to generate heat—were discussed. However, this is merely interesting physiological information, not proof that weekly immersion leads to noticeable weight loss.
A separate review in the Journal of Thermal Biology warned that severe thermal discomfort during full immersion can increase the risk of drowning due to hypothermia or prolonged exposure to harmful water temperatures. Another review in Autonomic Neuroscience defines hypothermia as a core temperature below 35°C and lists possible symptoms, including shivering, respiratory depression, cardiac arrhythmias, brain dysfunction, hypotension, and muscle dysfunction.
Conclusion on Benefits
Thus, a short dip in cold water after intense exercise may help some people feel less exhausted the next day. It may also benefit those suffering from stress or sleep problems, depending on the protocol and individual characteristics. However, it currently does not deserve all the promises made by the health industry: being a fat burner, a brain enhancer, an immune upgrade, a miracle recovery, a character test, or a personality replacement in one steel tub. Cold water remains just water, even if marketing promises otherwise.