Cassandra, the beloved protagonist of the classic 1948 coming-of-age novel, "I Capture the Castle" writes: "Noble deeds and hot baths are the best cures for depression." While most doctors wouldn't go that far, an hour-long bath has benefits that go way beyond the relaxation and stress reduction most of us are familiar with.
According to a recent study from the National Centre for Sport and Exercise Medicine at Loughborough University in the U.K., “An hour-long hot bath can boost metabolic health and cause an anti-inflammatory response similar to exercise.”
It was a small study with surprising results: Ten sedentary men, attached to glucose monitors (which recorded changes in their blood sugar for 24 hours) bathed in 104-degree water one day. The next, they cycled hard enough to bring their body temperature up by about a degree, which is what happens in a hot bath, too.
The bathers burned an extra 126 calories per hour (equivalent to a 25-30 minute walk). That was still less than the energy used for cycling the same amount of time, but was an 80 percent increase in energy expended over not bathing.
In addition, participants who bathed had, on average, 10 percent lower peak glucose levels — a boon for diabetics, but also good for the metabolic health of those who don't have the disease. The finding was unexpected, according Steve Faulkner, lead author of the study, who was searching for alternatives to exercise that could help keep blood sugar levels low for people with diabetes. “We think the reason is that the bath may encourage the release of heat shock proteins, which may help lower blood sugar levels by improving insulin controlled glucose uptake," Faulkner said in a release from the university.
The benefits of a hot bath
Over time, and throughout various cultures, a hot bath (or saunas and steam sessions) have long been touted as important for overall wellness. Now scientists are starting to understand the underlying reasons for those health benefits: “Only recently has science begun to understand how passive heating (as opposed to getting hot and sweaty from exercise) improves health,” says Faulkner.
But don't think of a bath as a replacement for a workout, but an addition to it: "... although these findings are interesting, we would always encourage increased physical activity and exercise as the best way to maintain good health," says Faulkner. There are plenty of other benefits to exercise that you won't get from a soak, like those feel-good endorphins, muscle toning and cardiovascular strengthening.
But if you're in the mood for a bath, this preliminary study certainly seems to tip the balance from "me-time indulgence" to "health benefit."