A recent study performed at the University of Loughborough‘s National Centre for Sport and Exercise Medicine set out to raise the body temperature of its male participants by 1 degree, using either an hour of moderately paced cycling, or an hour in a hot (104 °F / 40 °C) bath.
Although cycling used up more calories overall, reclining in the tub did burn 130—around the same amount as a 30-minute walk.
Post-heating, the participants’ blood sugar was monitored for 24 hours and researchers discovered peak levels were 10 percent lower after a bath than after a cycle ride. The two activities also seemed to produce a similar anti-inflammatory response in the body.
These findings actually make a lot of sense in the context of spa and sauna traditions from around the world. Many cultures use passive heating (raising the body temperature and taxing the cardiovascular system without the use of strenuous exercise) as a form of healing and cleansing.
Most recently infrared saunas have been causing a buzz in the wellness world thanks to their laundry list of reputed health benefits. Heating the body from the inside out, instead of the outside in, using skin-penetrating infrared light waves, these saunas help with pain, inflammation, low energy and poor circulation. What’s more, they soothe the parasympathetic nervous system, helping the body unclench and cope with stress better.
Although certainly not an adequate replacement for regular exercise, passive heating does appear to have significant health benefits, and having a hot bath every week is an easy way to support your body’s natural functioning.