Regular tub bathing linked to lower heart disease risk

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In a new study, researchers found that regular tub bathing is linked to a lower risk of death from heart disease and stroke.

And the higher the ‘dose,’ the better it seems to be for cardiovascular health, with a daily hot bath seemingly more protective than a once or twice weekly one.

A linked editorial sounds a note of caution, however, because sudden death associated with hot baths is relatively common in Japan, where the study was conducted.

The research was conducted by a team from Osaka University and elsewhere.

Having a bath is linked to good sleep quality and better self-rated health, but it’s not clear what its long term impact might be on cardiovascular disease risk, including heart attack, sudden cardiac death, and stroke.

To explore this further, the researchers tested participants in The Japan Public Health Center based Study Cohort 1, a population-based tracking study of more than 61,000 middle-aged adults (45 to 59 years).

At the start of the study in 1990, some 43,000 participants completed a detailed questionnaire on their bathing habits and potentially influential factors: lifestyle, to include exercise, diet, alcohol intake, weight (BMI); average sleep duration; and medical history and current medicines use.

Each participant was monitored until death or completion of the study at the end of December 2009, whichever came first, with the final analysis based on 30,076 people.

During the monitoring period, 2097 cases of cardiovascular disease occurred: 275 heart attacks; 53 sudden cardiac deaths; and 1769 strokes.

The team showed that compared with a once or twice weekly bath or no bath at all, a daily hot bath was linked to a 28% lower overall risk of heart disease, and a 26% lower overall risk of stroke.

The frequency of tub bathing wasn’t linked to a heightened risk of sudden cardiac death, or with a particular type of stroke, called subarachnoid hemorrhage (bleed into the space surrounding the brain).

Further analysis of preferred water temperature indicated 26% lower and 35% lower risks of overall heart disease for warm and hot water, respectively.

This is an observational study, and as such, can’t establish the cause. The typical style of Japanese bathing also includes immersion to shoulder height, and this may be a critical factor.

Previous research has pointed to a link between heat exposure and heart disease prevention: this is because the effects of heat on the body are not dissimilar to those of exercise.

The study is published in the journal Heart.

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