Similar to moderate exercise
Frequent sauna use may therefore be linked to improved overall health, due in part to the effect of heat on the cardiovascular system. Moreover, these manifestations are similar to those observed during moderate-intensity physical exercise.
When people are in a sauna, their core temperature rises so they sweat more to cool down, a process facilitated by increased blood flow. They also have a higher heart rate and higher blood pressure. All this appears to have multiple positive effects.
When blood vessels are exposed to sustained heat for several minutes, they dilate to boost blood flow, thereby removing heat from the body and cooling us down.
"In time, this dilation mechanism helps to increase blood vessel elasticity and may thus explain the lowering of blood pressure," Lee said.
After exposure to heat, the body begins to cool but does not merely return to the baseline homeostatic temperature; it actually drops even lower. As a result, sleep quality increases, as people enter the same state as when they start to fall asleep and their body temperature drops.
Endorphins are also released into the bloodstream when the body is exposed to heat.
"This may be one of the reasons why we feel so good after a sauna, said Lee. “That same sensation of well-being may mask our aches and pains. They may not disappear completely, but we do feel better.”