Cardiovascular Benefits of Sauna Usage

If you’re anything like me, you love to be warm, and with warmth, often comes sweat. I moved from Pennsylvania to south Florida a few years back and I don’t think I’ve stopped sweating since. The combination of an active lifestyle, hot and humid weather year-round, and my love of saunas has kept a healthy lather of liquid sitting on my skin nearly every day. I don’t hate it – actually I love it! Often after my exercise session at the gym, I’ll spend another 10-15 minutes in the sauna getting my final sweat in because I find it relaxing and I assume it’s beneficial. But is it really? I think at this point, we all know exercise is beneficial for so many reasons that this article isn’t going to cover. However, what about the sauna? Does regular usage of the sauna have ACTUAL health benefits? As always, let’s dive into some research and see what the science says.

Let’s start by stating something that probably isn’t anything new to you: heart disease is the leading cause of death in the United States and has been for a long time. In 2016, the CDC reported that heart disease killed 635,260 people. Heart disease includes several types of heart conditions such as coronary artery disease and heart attacks. Many related conditions may contribute to heart disease, one of which is termed the “silent killer”, high blood pressure. Over 75 million American adults have high blood pressure, which is about 1 in every 3 adults and an additional 1 in 3 American adults have prehypertension. High blood pressure was a primary or contributing cause of death for more than 410,000 Americans in 2014. [5]

Sustained hypertension may accelerate structural changes to the arterial wall, potentially increasing the stiffness or “compliance” of the vessels. Vascular compliance is the ability of the vessels to expand and contract when pressure changes. Arterial compliance is an independent predictor of cardiovascular morbidity and mortality in hypertensive patients.[1] A main contributor to cardiovascular disease is a lack of arterial compliance or increased arterial stiffness.[4] A measurement used to examine arterial compliance is called pulse wave velocity (PWV), which is a calculated by measuring the time it takes for a pressure pulse to travel between two set points. In patients with less arterial compliance, PWV increases[1], and in patients with increased compliance, PWV decreases.1 This means healthy arteries would show a smaller PWV measurement.

With that said… does the sauna have any beneficial impact on the circulatory system?

A 2017 study evaluated the most immediate physiological and cardiovascular effects of a single Finnish sauna session in 102 patients, 56 of which were men and 46 women. The mean age (years) was 51.9 + 9.2, mean body weight (kg) was 82.7 + 16.0 and the mean body mass index (kg/m2) was 27.2. All participants were exposed to a traditional Finnish sauna, which is characterized by air with a relative humidity of 10-20%, 73 ○C, and sauna sessions lasting 30 minutes separated by a 2-minute warm shower at the halfway point. All participants successfully underwent the recommended protocol. Following the sauna treatment, physiological parameters were measured immediately post sauna treatment and at 30 minutes post treatment. Results of the study show statistically significant effects of sauna heat exposure on body temperature, heart rate, and blood pressure values. See chart below:
 

Laukkanen, T., Kunutsor, S. K., Zaccardi, F., Lee, E., Willeit, P., Khan, H., & Laukkanen, J. A. (2018). Acute effects of sauna bathing on cardiovascular function. Journal of human hypertension, 32(2), 129.
 
(It is important to note from the study that all participants chosen were asymptomatic [no cardiovascular symptoms], but had at least one conventional risk factor such as history of smoking, hypertension, dyslipidemia, obesity, or family history of coronary heart disease. No participant had any abnormal cardiovascular symptoms after their 30 minutes of sauna bathing session.)

This data clearly shows that as body temperature rises from the sauna, blood pressure, both systolic and diastolic, decrease immediately post sauna session and remained lower 30 minutes after the sauna session was complete. We also see PWV did the same thing – decrease immediately and 30 minutes post session. These are all positive changes within the vascular unit due to just a single sauna session. The authors concluded that their study showed sauna bathing led to significant decreases in blood pressure, potentially because of the acute vasodilation.

So far, we see that a single 30 minute sauna session appears to have a beneficial impact on our cardiovascular system. Now, the next question is, are there longer term studies? If so, what do they show?

A cohort study published in 2015 investigated the association between sauna bathing and fatal cardiovascular and all-cause mortality events. The study completed baseline examinations from 1984 to 1989 on 2315 men. Participants had a mean age of 51.1 and mean BMI of 26.9. The study assessed sauna bathing by a self-administered questionnaire. During a median follow-up of 20.7 years, 190 sudden cardiac deaths, 281 fatal coronary heart diseases, 4017 fatal cardiovascular diseases, and 929 all-cause mortality events occurred. The study showed that participants with a higher per week frequency of sauna bathing had a reduced mortality risk of coronary heart disease and cardiovascular disease. Compared to participants who completed just one sauna visit per week, the risk of fatal coronary heart disease was 23% lower for participants who completed 2-3 sauna bathing sessions per week and 48% lower for 4-7 sessions per week. The mean duration of sauna baths in the study was 14.2 minutes, but ranged from 2-90 minutes. [3]

I have long been a sauna user and lover – again, I like to be warm. Before diving into the research, I would have never guessed that by relaxing in the warmth of the sauna for approximately 60 minutes a week (15 minutes X 4 sessions per week), I could reduce my risk of fatal coronary heart disease by nearly 50%! That’s honestly an insane number when you consider that using the sauna is literally just sitting in a different room than you might otherwise sit in.

Now, before you finish reading and click the next article, there are some potential contraindications to be aware of. Sauna bathing appears to be safe for patients with stable cardiovascular disease, However, sauna exposure could potentially be harmful in patients with symptomatic and unstable disease conditions. Alcohol consumption in combination with sauna baths has been linked to sudden death as it increases the risk of hypotension, cardiac complications, and traumatic events. [2] If you think you may be experiencing any medical conditions or have experienced medical conditions that would be contraindicated due to sauna exposure, always contact your physician prior to beginning any new program to be sure you are cleared for the activity.

If you are determined to be fit for sauna exposure, it appears sauna bathing is not only relaxing, but also extremely beneficial to our cardiovascular system as it reduces mortality due to decreased arterial stiffness. Just remember to always wear a towel!

References

1. Cecelja, M., & Chowienczyk, P. (2012). Role of arterial stiffness in cardiovascular disease. JRSM cardiovascular disease, 1(4), 1-10.
2. 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.
3. Laukkanen, T., Khan, H., Zaccardi, F., & Laukkanen, J. A. (2015). Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA internal medicine, 175(4), 542-548.
4. Laukkanen, T., Kunutsor, S. K., Zaccardi, F., Lee, E., Willeit, P., Khan, H., & Laukkanen, J. A. (2018). Acute effects of sauna bathing on cardiovascular function. Journal of human hypertension, 32(2), 129.
5. “National Center for Health Statistics.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 17 Mar. 2017, www.cdc.gov/nchs/fastats/leading-causes-of-death.htm