Wanna Sauna?

There’s been a recent wave of health & fitness influencers making huge claims regarding the benefits of sauna; rarely do we really sit down & look at the scientific data behind these type of claims.

Saunas, the small enclosures used to experience extreme heat & profuse sweating, originate from Northern Europe, and have been around for over 2,000 years. “Sauna” is a Finnish term that means "bath" or "bathhouse” – fittingly. Let’s look over what the literature highlights as the potential health benefits & risk factors that are associated with saunas.

Hopefully, by the end of this review, you’ll have a good idea about if sauna would be a worthwhile addition to your lifestyle.

As sedentary & mundane our day-to-day has become, our lifestyles are often still extremely demanding and hectic; the opportunity to unwind and de-stress is priceless. Stepping into a sauna's warm, tranquil environment allows us to escape the fast-paced world outside. Without opening a textbook or reading an article, we know that that heat helps to relax our muscles, relieve tension, & melt away our stress. But what’s really happening at the physiological level?

Prolonged exposure to the high temperatures of a sauna will quickly lead to potent cardiovascular, integumentary, & endocrine effects. The temperature of the skin rises rapidly, followed by a transient increase in core body temperature.  The heart rate soars & cardiac output may increase by up to 70% as well (Hannuksela & Ellahham, 2001).

Over half of the circulating blood is redistributed from the core to the skin, causing profuse sweating & fluid loss. According to findings by Huhtaniemi & Laukkanen, the profuse sweating in response to sauna bathing leads to increased production of antidiuretic hormone,  norepinephrine level increases, and the activation of the renin–angiotensin system. All of these changes work to prevent abnormal drops in your blood pressure.

A not-so-well-known benefit of sweating is that it facilitates excretion of heavy metals such as aluminum & lead at a much higher rate than what you’d see through urination (Genuis et al., 2011); speaking to the saunas ability to indirectly assist the body in purging toxic chemicals.

Sauna has been shown to have some impressive long-term cardiovascular effects as well. Similarly to the effects of exercise, regular sauna use leads to decreased blood pressure (Laukkanen et al., 2018); lower heart rate (Lee et al., 2018) & leads to overall improved circulation.

Regarding endocrine effects, the secretion of anterior pituitary hormones such as growth hormone, which increases energy, muscle mass, & bone density, is boosted. Similarly, β-endorphins, our “feel good hormones”, are also released at an increased rate with the body becoming more sensitive to the endorphins (Huhtaniemi & Laukkanen, 2020).

Chronic inflammation plays a major role in the development of many diseases; most notably, cancer & Type II diabetes (Chung et al., 2019). Aging, in general, is associated with progressively increasing inflammatory biomarkers. Recently, saunas have been shown to have a powerful influence on inflammation. Similar to exercise, sauna use elevates the core body temperature, acutely increasing IL-6 & IL-10 levels; a net anti-inflammatory reaction (Hoekstra et al., 2020).

Sauna use has also been shown to reduce blood levels of C-reactive protein, another major inflammatory biomarker. In a 2018 study done by Laukkanen, following 2,000 men, it was shown that the more frequently one utilized the sauna, the lower their CRP levels.

We could point to the benefits all day, but extreme heat is not safe or ideal for everyone. Some special populations should be a touch more cautious with their sauna use. If you struggle with heart or vascular issues, the acute stress of a sauna & resulting cardiovascular effects may potentially spur an adverse incident. Sauna use has typically been contraindicated in those who’ve experienced heart attacks or heart failure, though the research in that regard is slowly beginning to say otherwise (Källström et al., 2018). It may also be dangerous for young children & the very elderly to utilize the sauna, as they have been shown to have noticeably less thermoregulatory capacity.

Some women who frequent the sauna may experience disturbances in menstrual cycle; though, no lasting effects on fertility have been reported. The hormone responses are short-lived, normalizing soon after sauna exposure during the recovery (Huhtaniemi & Laukkanen, 2020).

If you & your spouse are trying for a pregnancy, consider that sperm production may be momentarily reduced in men following regular or irresponsible sauna use; though, again, regular sauna use has not been shown to cause reduced fertility (Huhtaniemi & Laukkanen, 2020).

All things considered; saunas offer a ton of benefits for both our physical & mental well-being. From relaxation and stress relief, to detoxification, improved circulation & cardiovascular health, hormonal boosts & recovery. Take a look through the literature & consult with a trusted medical professional; a regular sauna may be the perfect addition to your life to help you let off some steam!

References & Works Cited

Patrick, R. P., & Johnson, T. L. (2021). Sauna use as a lifestyle practice to extend healthspan. Experimental gerontology, 154, 111509.

Hannuksela, M. L., & Ellahham, S. (2001). Benefits and risks of sauna bathing. The American journal of medicine, 110(2), 118-126.

Huhtaniemi, I. T., & Laukkanen, J. A. (2020). Endocrine effects of sauna bath. Current Opinion in Endocrine and Metabolic Research, 11, 15-20.

Genuis, S. J., Birkholz, D., Rodushkin, I., & Beesoon, S. (2011). Blood, urine, and sweat (BUS) study: monitoring and elimination of bioaccumulated toxic elements. Archives of environmental contamination and toxicology, 61, 344-357.

Laukkanen, J. A., Laukkanen, T., & Kunutsor, S. K. (2018, August). Cardiovascular and other health benefits of sauna bathing: a review of the evidence. In Mayo clinic proceedings (Vol. 93, No. 8, pp. 1111-1121). Elsevier.

Lee, E., Laukkanen, T., Kunutsor, S. K., Khan, H., Willeit, P., Zaccardi, F., & Laukkanen, J. A. (2018). Sauna exposure leads to improved arterial compliance: findings from a non-randomised experimental study. European journal of preventive cardiology, 25(2), 130-138.

Chung, H. Y., Kim, D. H., Lee, E. K., Chung, K. W., Chung, S., Lee, B., Seo, A. Y., Chung, J. H., Jung, Y. S., Im, E., Lee, J., Kim, N. D., Choi, Y. J., Im, D. S., & Yu, B. P. (2019). Redefining Chronic Inflammation in Aging and Age-Related Diseases: Proposal of the Senoinflammation Concept. Aging and disease, 10(2), 367–382. https://doi.org/10.14336/AD.2018.0324

Hoekstra, S. P., Bishop, N. C., & Leicht, C. A. (2020). Elevating body termperature to reduce low-grade inflammation: a welcome strategy for those unable to exercise?. Exercise Immunology Review, 26, 42-55.

Källström, M., Soveri, I., Oldgren, J., Laukkanen, J., Ichiki, T., Tei, C., ... & Hägglund, H. (2018). Effects of sauna bath on heart failure: A systematic review and meta‐analysis. Clinical Cardiology, 41(11), 1491-1501.