Though some dermatologists believe showers can be better for your skin by helping it to retain some naturally occurring oils, baths are still symbolic of relaxation. Luxuriating in standing water provides a break in routine and allows people to unwind.
Now, scientists may have found evidence that there’s a more substantial benefit to bathing: It might actually help alleviate depression.
In a study [PDF] out of Freiburg University in Germany and published by the preprint repository bioRxiv, 45 subjects with moderate to severe depression as measured by the Hamilton Depression Rating Scale (HAM-D) were instructed to either exercise for 45 minutes twice each week or take 30-minute hot baths (at 104°F) and then relax with hot water bottles and a warm blanket for 20 minutes twice a week. The subjects were then retested with HAM-D after eight weeks. Those who bathed reported a six-point drop in their score, which averaged 21.7 on a scale of 1 to 50 at the outset. Exercise patients saw only a three-point drop.
There are some significant caveats to this study, which has not yet been peer-reviewed. In addition to the sample size being small, 13 of the 23 people assigned to the exercise group failed to complete the study because they were unable or unwilling to continue physical activity.
Some researchers suggest that soaking can address one's mood by helping to normalize a person’s body temperature and circadian rhythms, which help regulate the sleep-wake cycle. (The hot water bottles provided a continued spike in body temperature.) A 2017 study led by the University of Madison-Wisconsin demonstrated that regularly raising a individual's core temperature to 101.3°F led to a 4.27-point reduction in the HAM-D score after six weeks (though the findings from the small-scale study were controversial).
While it’s too early to conclude whether hot baths should be a prescription for depression, or that their benefits are equal to those of exercise, they have almost no side effects and are likely to result in more adherence than an exercise regimen.
[h/t New Scientist]