Introduction
Cold plunges and cold showers are rampant on social media, seemingly shown to improve everything from immunity to energy. But those benefits mostly come down to lore and tradition; no randomized controlled trial has actually been conducted to show that regular cold showers make healthy people healthier until now. Dutch researchers conducted a massive experiment to prove the effectiveness of this practice once and for all. Their hypothesis was easy and practical: if average adults took a cold blast at the end of their regular shower for 30 days, would they see a reduction in illnesses?
Methods
The team recruited 3,018 healthy 18-65yr olds who were not already habitually having cold showers. They were randomly assigned to four conditions, where three conditions involved, as part of their normal warm shower, 30, 60, or 90 seconds of cold water (cold shower for 30 days), while the control group just had their usual cold shower. Participants were able to continue their cold shower for a further 60 days post the experiment if they wished. Outcomes were self-reported via the internet, with the primary outcomes being the number of days sick and the number of days absent from work with illness.
Results
Both of the cold shower groups took 29% fewer sick days off than the control group, which was a statistically significant reduction. One surprising point is that they did not show any obvious decrease in days feeling sick, so cold showers might be more useful in mitigating how bad the illness felt or in its ability to interfere with daily life rather than the illness ever manifesting. The amount of time spent on the cold showers did not make a difference; ranging from 30 to 90-second showers worked just as well. Most surprisingly, despite the initial discomfort, 91% said they wanted to continue taking cold showers every day, and many felt they gained the same effect as drinking caffeine, as they were in a better mood and felt more energy. The interesting part of this study is the sheer simplicity of the intervention. Up until now, there was never any indication that doing a simple and inexpensive thing like taking a cold shower could potentially have any health-related benefit.
Conclusion
There is no suggestion that cold showers will save us all, and the authors were careful to include that the results are self-reported. The test subjects were already perfectly fit and well-trained; however, the study still matters, proving that a health action that was previously only a rumor to be addressed in gyms and on the internet has science to back it up. The results at least partially suggest that getting colds is reduced, just by standing under 30 sec of icy water. It is always wonderful if some of the world’s health secrets are readily available, as simple to follow, and it’s even more wonderful when those health crazes have such reliable, good origins.
