Fire & Ice
Exploring the health benefits of thermal stress
It’s great to be back after a restorative week with my family and colleagues at the Institute for Functional Medicine Annual International Conference (AIC). This year the conference was held in Orlando, FL, which meant plenty of sunshine, pool time, and Oliver’s first visit to Disney (cue the “mom happy tears”). It was a special trip for all.
As promised, I will be sharing highlights from this year’s conference in my newsletter over the next few months. This week’s edition will focus on the health benefits of thermal stress (i.e. sauna). This “hot topic” (pun intended) is one that is near and dear to my heart as it has cultural significance to the people and place I call home.
Fire & Ice - The Health Benefits of Thermal Stress
Here we go - let’s take a deep dive into the health benefits of thermal stress. Chances are you’ve tried a sauna (at least once) or are familiar with the concept. While sauna usage is gaining popularity much in part to influencers within the wellness space, “sauna bathing is deeply rooted in Finnish culture and has been used for thousands of years for leisure, relaxation, and wellness”.
In her talk entitled, “Challenging Yourself with Thermal Stress to Improve Health”, researcher Dr. Rhonda Patrick shared some of the emerging research around this important topic. Below you’ll find an overview of the potential health benefits and proposed physiological mechanisms.
As you can see, the potential health benefits and indications for sauna bathing are vast. Below are a few key takeaways:
Sauna mimics moderate aerobic activity - When comparing BP and HR during the sauna session with the response during an exercise test, sauna bathing was equivalent to an exercise load of 60-100 watts.
Sauna improves heart function - Both systolic and diastolic BP improve with long-term sauna usage resulting in improved vascular compliance, left ventricular function, and improved endothelial function.
Sauna improves heart rate variability - During the cooling down period from sauna bathing, heart rate variability (HRV) increases which indicates better stress adaptation between the sympathetic (fight-or-flight) and parasympathetic (rest-digest-recover) nervous systems. Anecdotally, most people (myself included) will say that they sleep the best after a sauna, which is likely due in part to improved HRV.
Now that you know a bit more about the health benefits of sauna bathing, you may be wondering what is the effective “dosage” to achieve these outcomes? Here’s what the research recommends:
Finnish Sauna Parameters
Duration: > 19 minutes
Temperature: 174 degrees F
Frequency: 4-7 times/week was most robust
2-3 times/week had positive effects
Of note, the preliminary research suggests that sauna type matters in terms of health outcomes. Infrared saunas improve some cardiovascular markers, but aren’t as robust as Finnish style saunas.
With any new lifestyle habit, safety is of the utmost importance. It is always best to check with your personal healthcare clinician before starting any new activities such as sauna bathing. Below are some sauna safety considerations:
Sauna bathing is generally well-tolerated and a safe activity for most healthy people as well as most people with stable heart disease
It’s important to rehydrate after using the sauna. Avoid alcohol use with sauna bathing.
Sauna bathing is not advised (contraindicated): Recent heart attack (myocardial infarction), unstable angina, severe aortic stenosis, elderly people prone to low blood pressure, and pregnancy.
My sauna culture immersion began twenty years ago when I moved to the northern-most part of Upper Michigan to attend Michigan Technological University. Although I grew up only 100 miles away, I never knew about the deeply rooted Finnish culture in this community. I’m told that per capita this region has the greatest number of Finns outside of Finland IN THE WORLD. Saunas are everywhere - in the dorms, the fitness centers, and in most homes. In fact, we have two saunas (an electric hot rock in our home and a wood fired sauna at our cabin featured above).
After completing residency, I returned to the Keweenaw to begin my career as a family physician. I soon learned the importance of saunas and their connection to well-being through my patients’ lives and stories. They often shared how sauna bathing was a daily habit (not unlike exercise) and was essential for stress management, good sleep, and generally touted as “good for what ails you”.
Furthermore, I learned how sauna bathing brought people together. In the summer months, family and friends gather on weekends for all-day sauna bathing (accompanied by jumps in a nearby lake or stream), potlucks, and connection. While I haven’t seen it cited in the literature yet, I suspect that the multigenerational, communal aspects of sauna culture also influence the positive health benefits observed within the Finnish population. Sauna bathing as a conduit for connection…that’s a prescription I’d love to write.
Is sauna bathing part of your healthy lifestyle? What effects do you observe? Send me a message or leave me a comment below.
In the Garden
Just a quick update to say that our garden is in by June 15th, which is our typical zone 5 target and was a bit of a scramble this year given our recent trip. The rain and cooler temps were much welcomed this week after yet another hot and dry start to the planting season.
I’m happy to share that our initial trial with the Swift Blocker was a great success. If you are a soil blocker, you MUST check out the Swift Blocker (Bonus- the Swift Blocker is Michigan made and the owners are longtime friends of ours). This product is truly changing the soil blocking industry. As the blocker fits perfectly in a 1020 tray, I can now soil block 200 cells in a matter of minutes as opposed to hours of use with my former 4 cell hand blocker.
One to Follow
As we are coming into farmer’s market season, here’s one of my go-to newsletters for delicious, seasonal recipes & tips :
by Brooks Reitz features “little techniques, simple tricks, new discoveries - mostly for the food lover, but for any curious person who wants to uncover what is interesting.” It’s an excellent and enjoyable read with plenty of practical tips for making the most out of your market season.This newsletter is a work in progress and your feedback is valuable to me. If there are topics of interest or columns you’d like featured, please connect with me and/or leave a comment. Thanks for being here!
Yours in health,
Dr. Michelle
P.S. If you are enjoying this newsletter, I’d love if you’d share it with a home cook, gardener, and/or nature lover in your life!
Love this post Michelle! Thank you for sharing 🙏🏽
Such interesting information about the Saunas. Both me and my partner loves saunas and would love to have one at home. Currently we are lucky enough to use the one in the local Leisure Centre which is just a few min walk away.
I grew up in Sweden, where there also is a sauna culture, but not as strong as in Finland, it was interesting to hear not only of the benefits but also that the Finns who have emigrated brought their sauna culture with them!