Dr Steve Faulkner and his team recruited 14 adults to take an hour-long soak at 40 degrees and take part in a 60-minute bike ride. The two tests were designed to raise core the body temperature by one degree so the team could asses how many calories were burned in each session.
While biking did burn more calories, the hot bath was found to be as effective as a 30-minute walk. And while the researchers couldn’t pinpoint exactly why this happens, Dr Faulkner told The Conversation he believes a likely explanation is the “increased energy demand to maintain heat balance, to ensure the body doesn’t get too hot or cold.” Translation: we have to work harder to balance our internal temperature gauge, resulting in more calories burned.
In addition, the bath had a significant impact on the participants' blood sugar levels – a factor that could help to prevent type 2 diabetes.
“The overall blood sugar response to both conditions was similar, but peak blood sugar after eating was about 10 per cent lower when participants took a hot bath compared with when they exercised,” Dr Faulkner said.
Plus, it triggered an anti-inflammatory response similar to one that might occur after exercise. This is especially important for boosting the immune system and warding off disease.
“This suggests that repeated passive heating may contribute to reducing chronic inflammation, which is often present with long-term diseases, such as type 2 diabetes,” Faulkner added.
As if we needed another excuse to break out the bubble bath.