OSAKA, Japan — Dust off the rubber duckies. A new study finds that taking a nice hot bath on a daily basis can reduce one’s risk of dying from cardiovascular-related issues (heart attack, stroke). While taking a bath once or twice a week is beneficial, researchers found that daily bath takers were in even better shape. Essentially, the more often you hop in the tub the better.
Unwinding after a long day with a relaxing bath has already been linked to improved sleep quality, but up until now the tub’s influence on one’s heart health had been largely unclear. So, the study’s authors analyzed data originally collected during a prior long-term population based tracking project that followed tens of thousands of middle aged (45-59 years old) Japanese adults.
At the beginning of that project, in 1990, all participants filled out surveys on their bathing habits as well as other lifestyle indicators like exercise routine, diet, alcohol intake, BMI, sleep habit, and medical profile. Since then, all the participants were monitored until they passed away or until the project ended in December 2009. In all, 30,076 people were tracked.
Over the course fo the study, a total of 2,097 cases of cardiovascular disease appeared, as well as 275 heart attacks, 1,769 strokes, and 53 sudden cardiac deaths.
A further analysis of those incidents revealed some striking benefits related to the bath. In comparison to those who only took a bath once or twice per week, or took no baths at all, individuals taking a hot bath daily had a 28% lower risk of developing cardiovascular disease and a 26% lower overall risk of suffering a stroke. This held true even after researchers accounted for other potentially influential lifestyle factors.
However, how often someone took a hot bath wasn’t associated with risk of sudden cardiac death or a subarachnoid hemorrhage (a specific type of stroke).
Water temperature appears to play a big role in this relationship; while “warm” water was calculated to result in a 26% lower risk of overall cardiovascular disease, “hot” water brought about a 35% lower risk. That being said, water temperature didn’t show the same risk fluctuations regarding stroke risk.
These findings are fascinating, but the research did have some limitations. First of all, this was an observational study so by its very definition it can’t establish a cause behind the benefits. Moreover, possible changes in the participants’ bathing habits weren’t periodically updated over the course of the initial research period.
It’s also worth mentioning that the traditional Japanese style of taking a bath means immersing oneself in water up to the shoulders. This may have played a role in the findings.
Still, lots of previous research has suggested that heat exposure is beneficial for the heart, and these results corroborate those findings. The effect of heat on the human body, to a certain extent of course, is quite similar to exercise.
“We found that frequent tub bathing was significantly associated with a lower risk of hypertension, suggesting that a beneficial effect of tub bathing on risk of cardiovascular disease may in part be due to a reduced risk of developing hypertension,” the study reads.
Beyond the cardiovascular benefits, however, particularly hot baths may represent other health hazards for older individuals.
“There can be no doubt about the potential dangers of bathing in hot water, and the occurrence of death from this increases with age, as well as with the temperature of the water. Although cardiovascular disease itself is unlikely to be the cause of these deaths, overheating, leading to confusion and drowning, most likely is,” comments Dr. Andrew Felix Burden. “Investigations into the potential cardiovascular benefit of heat-free immersion in warm to hot water are needed. In the meanwhile, caution is needed because of the higher mortality associated with such bathing in an unselected population.”
The study is published in Heart.