Whenever a new study identifies a sedentary activity that miraculously burns calories, we're all ears. When that activity is taking a nice, long soak in your bathtub, we're tempted to cancel our weekend plans and have a mini spa session at home.
Curious about the effects of "passive heating" on the body (as opposed to working up a sweat through exercise), researchers from Loughborough University decided to look at how a hot bath affects your health. In short, they found that sitting in the tub for an hour has a similar calorie-burning effect as going on a half-hour walk outside (around 140 calories burned). What's more, taking a soak can also reduce chronic inflammation in the body, "which is often present with long-term diseases, such as type 2 diabetes," explains Steve Faulkner, a research associate at the university.
To arrive at this conclusion, the study authors recruited 14 healthy, non-smoking men with no history of cardiovascular, hematological, or metabolic disorders to participate in the study. They were assigned to either an hour-long soak in a hot bath (at 104 degrees) or an hour of cycling on a bike. Both activities were designed to raise core body temperature by one degree over the course of an hour.
While the cyclers burned more calories than the bath-dwellers, a hot bath still resulted in a pretty significant calorie burn for just submerging your body in hot water for an hour. "These activities … may have health benefits for people who are unable to exercise regularly," concludes Faulkner. "Hopefully our future investigations, coupled with those of other groups worldwide, will help to establish the true potential of passive heating as a therapeutic tool."
For more, read up on the one exercise that may slow down the aging process.