Heat Exposure and Mind/Body Wellness

Scientific research investigating the effects of heat exposure, such as that experienced in a sauna, demonstrates a range of health-enhancing physiological and psychological benefits.   One study found that men exposed to a sauna 4-7 times a week for approximately 19 minutes per bout had 52% reduction in sudden cardiac death when compared to those spending 11 minutes or less in the sauna.  The 4-7 times per week sauna dose also resulted in a 50 percent reduction in cardiovascular-related mortality compared to one time per week. The researchers found men who used the sauna 2-3 times per week had a 24 percent reduction in all-cause mortality when compared to the men who had one sauna experience per week. More exposure, 4-7 times per week, resulted in a 40 percent reduction in all-cause mortality.  

Heat stress mimics moderate intensity aerobic exercise, increasing heart rate and blood pressure, while elevating body core temperature and increasing sweat rate. A study demonstrated reductions in blood pressure following bi-weekly sauna use over a three-month period, with mean blood pressure reducing from 166/101 to 143/92 mmHg in 46 hypertensive patients and from 162/110 to 139/92 mmHg in 180 hypertensive patients. These changes may result from a balance to the autonomic nervous system and an improvement in vessel function, reducing arterial stiffness.  Heart rate can be elevated in a sauna experience similar to that of a moderate intensity aerobic activity, providing some cardiovascular benefit. The attributes of people with poor cardiorespiratory fitness were analyzed among a population of 1 million people, uncovering that there was a 75 percent greater risk of experiencing depression in association with poor aerobic fitness. There is a strong link between a high-functioning cardiovascular system and optimal brain health.

 In the sauna, blood flow does get redistributed to the skin for cooling; however, blood flow in general is improved to the brain and to the muscles. Brain-derived neurotrophic factor (BDNF) is one of the most active of a family of proteins called neurotrophins, which help to control and stimulate neurogenesis (the growth of new neurons). BDNF increases with exercise and is important to long-term memory and has a neuroprotective effect on brain cells while impacting mood regulation and cognition. Exercise in combination with heat stress has been shown to increase BDNF more effectively than exercise alone. Researchers found that people who use a sauna 4-7 times per week had a greater than 60 percent reduction in dementia and Alzheimer’s risk compared to people who only use it once per week. People who use it 2-3 times per week have a 27% reduction in risk—it is a dose-dependent relationship.  

Sauna use, providing heat stress, results in a significant increase in the release of endorphins. They are considered “feel good” neuropeptides associated with stress reduction, mood elevation and reductions in the sensation of pain. The term endorphin is a contraction of endogenous (originating within the body) and morphine and is considered an endogenous opioid neuropeptide used in the body as an analgesic to numb or dull pain.

The evidence is clear that heat exposure may contribute to a fit cardiovascular system, influence brain health and cognition, may reduce the incidence of neurodegenerative disease, elevate mood and mental health and reduce pain. Heat exposure may occur gradually, modifying the temperature and the duration of the exposure over time as we become acclimated. With this in mind, it is not necessary to start with an actual sauna, especially if you have very little previous heat exposure experience. Being mindful that heat can be health-enhancing is a great first step towards adopting behaviors that allow for an elevated heat episode. It is imperative to stay well-hydrated before, during and after heat experiences, and it is always best to confer with your physician before you begin any new health protocol.