Sauna Use as an Exercise Mimetic for Heart and Healthspan
Several studies have shown that frequent sauna bathing (4-7 times per week, 174°F for 20 min.) is associated with a 50% lower risk for fatal heart disease, 60% lower risk for sudden cardiac death, 51% lower risk for stroke, and 46% lower risk for hypertension. Just a single sauna session has been shown to lower blood pressure, improve heart rate variability, and improve arterial compliance.
Some of the positive benefits of the sauna on heart health may have to do with similar physiological changes that also occur during physical exercise. For example, there is a 50-70% redistribution of blood flow away from the core to the skin to facilitate sweating. You start to sweat. Heart rate increases up to 150 beats per minute which correspond to moderate-intensity physical exercise. Cardiac output (which is a measure of the amount of work the heart performs in response to the body’s need for oxygen) increases by 60-70%. Immediately after sauna use, blood pressure and resting heart rate are lower than baseline similar to physical activity.
Sauna as a potential tool for longevity and healthspan
In addition to lowering cardiovascular-related mortality, sauna use may have benefits for overall longevity. For example, using the sauna 2-3 times per week is associated with 24% lower all-cause mortality and using the sauna 4-7 times per week is associated with 40% lower all-cause mortality. Sauna use is also associated with a lower risk of age-related diseases like Alzheimer’s disease.
People that used the sauna 2-3 times per week had a 20% lower risk of Alzheimer’s disease, and those that used the sauna 4-7 times per week had a 60% lower risk of Alzheimer's disease, compared to men that used the sauna 1 time per week.
Some of the longevity benefits of sauna use may have to do with an increase in heat shock proteins, which is one of the protective adaptive responses to heat stress. Heat shock proteins have been shown to prevent and slow the progression of neurodegenerative diseases like Alzheimer’s disease and Parkinson’s disease, slow human muscle atrophy, and are associated with human longevity.
The effects of heat stress on longevity have also been shown in lower organisms including flies and worms, increasing their lifespans by as much as 15 percent. The mechanism of lifespan extension was also teased out in these organisms and shown to be specifically dependent on heat shock proteins. The productions of heat shock proteins in response to heat exposure is an evolutionarily conserved mechanism from lower organisms like flies and worms, to animals to humans.