Can Sauna Therapy Improve Cognitive Health?

by Eva Coles MS, RDNLifestyle
Woman in a sauna

Do you go to the sauna? Well if the answer is no, you may want to consider adding it to your wellness routine. This ancient practice has been associated with a number of health benefits, including improved circulation, cardiovascular health, immune function, and extended lifespan. But what of its effects on cognitive function, Alzheimer’s disease, and dementia? 

This post will cover some background on sauna bathing, the research supporting its anti-aging health benefits, and what is known regarding sauna use and cognitive health.

So What Is a Sauna?  

The term sauna is a Finnish word referring to the bath or bathhouse [2]. It to comes from an old Sámi word meaning “earth pit” or “snow pit” [3]. This is because the earliest form of saunas in Finland were literal pits dug into slopes, covered, and heated with rocks which people “bathed” in during the winter [3]. 

Sauna use, known as sauna bathing, is a form of heat bathing that dates back thousands of years, with construction, heat source, and humidity level varying based on culture:

  • Russians Banyas, thought to have originated around 1,000 BC, used steam or dry heat [4]
  • Turkish Hammams, which are similar to Roman Baths, originated in 300 BC [5]
  • Native Americans built sweat lodges for purification and ceremonial purposes [2]
  • Finnish baths (saunas) use dry air and high temperatures. They inspired the unpainted wood-paneled saunas we see today [2].

Today, a sauna generally refers to a room designed as a place to experience whole-body thermotherapy in the form of dry (10% humidity) or wet (50%+ humidity) heat of 45-100 °C or 113-212 °F [2]. Saunas are typically heated with conventional electric heating systems or infrared heaters. The main difference between the two is that conventional heaters require more heat to raise core body temperature whereas infrared heaters emit thermal radiation which heats the body from within. 

Another important distinction to make is that wet saunas, or steam rooms, cannot reach the same level of heat as dry saunas because the humidity makes them feel subjectively hotter [2]. So, for the purposes of this article, we are going to focus on dry saunas.

A Bit of Science

The benefits of sauna bathing are largely attributed to the formation and action of heat-shock proteins [2]. Put simply, these proteins are activated in conditions of stress, such as heat, to prevent protein misfolding or damage [2]. This means that they will go around the body and repair or re-synthesize damaged proteins [2]. Prolonged exposure to heat eventually leads to improved bodily resilience and heat tolerance, which has been associated with longevity. Importantly, these health improvements appear to be related to with repeated sauna sessions [2].

Some important benefits include slowed muscle atrophy, protecting against neurodegenerative disease, and protecting against cardiovascular disease. 

Sauna Health Benefits

Cardiovascular Protection:

  • Lower blood pressure: sauna use has been associated with 25-45% reduced risk of hypertension [2]. 
  • Improve endothelial function: sauna bathing has been proven to promote normal blood vessel dilation and contraction [7]. 
  • Lower cholesterol: two studies showed that seven to ten 30-45 minute sauna baths in a 2-3 week period significantly reduced LDL cholesterol in men and women [8,9]. 
  • Reduce inflammation: a study from Finland found that more frequent sauna use was associated with lower C-Reactive Protein (CRP), a marker for cardiovascular disease [10]. Even more, 15 minute sauna sessions have been shown to increase IL-10, a potent anti-inflammatory protein [11]. 

Note: Several randomized control trials (the gold standard of research) also found improvements in subjects with congestive heart failure, ischemic heart disease, and peripheral artery disease after regular sauna bathing [2]. 

Cognitive Protection:

  • Neurogenesis stimulation: sauna use can boost production of brain-derived neurotrophic factor (BDNF)
  • Improved cerebral blood flow: through improved blood pressure and endothelial function [7]
  • Reduced inflammation
  • Reduced protein aggregation: via the action of HSPs, which may act directly on beta amyloid protein aggregation [13]. 
  • Improved glycemic control: regular sauna bathing has been shown to improve insulin sensitivity [14]

Note: A paper published in 2020, following 14,000 FInnish men and women for 39 years, found that frequent sauna use was associated with reduced risk for developing dementia [15]

What About Alzheimer’s?

I thought it would be helpful to reiterate some of the benefits of sauna bathing in the context of different subtypes of Alzheimer’s disease:

  • Inflammatory Alzheimer’s (IA): Regular sauna bathing has been shown to reduce markers of IA such as CRP, IL-6 , and increase the anti-inflammatory protein IL-10.
  • Vascular Alzheimer’s (VA): sauna use can improve vascular function, blood flow to the brain, and lipid status
  • Glycotoxic Alzheimer’s (GA): sauna bathing can improve glycemic control, improve insulin sensitivity, and potentially mitigate the cognitive burden of this subtype. 

Uses & Safety Considerations 

Typically, a sauna session involves passively sitting in temperatures ranging from 45-100 °C or 113-212 °F for 5-20 minutes. This time-frame is traditionally interspersed with cooling or cold exposure, which many believe have amplifying effects when combined with heat exposure. 

As mentioned earlier, there seems to a dose dependent relationship between sauna use and health benefits, so regular use of 2-7 times per week is recommended [2]. 

Generally, sauna use is considered safe for most, however, you should avoid exceeding 30 minutes per session. 

Contact your doctor or licensed healthcare provider to make sure that sauna bathing is safe for you. 

Takeaways  

Sauna bathing has gained widespread popularity for its potential to increase longevity and reduce all-cause mortality [12]. While this practice may provide numerous health benefits, it is important to keep in mind that there have been no studies looking directly at sauna use and neurodegenerative disease progression or severity. So, we should not expect sauna therapy to be a “cure all” strategy. That being said, the advantages are compelling enough to conclude that it would likely only benefit anyone to incorporate sauna bathing to their wellness routine, especially if they are unwilling or unable to exercise. If you are concerned about your cognitive function or brain health, contact the Amos Institute today to speak to a dietitian certified in a functional medicine approach. 

P.S. After completing this blog post, I went for a long sauna bath.

References:

  1. Laukkanen et al., 2018: https://doi.org/10.1016/j.mayocp.2018.04.008 
  2. Patrick & Johnson, 2021: https://doi.org/10.1016/j.exger.2021.111509
  3. https://www.alpinesauna.com/sauna/saunas/
  4. https://en.wikipedia.org/wiki/Banya_(sauna)
  5. https://en.wikipedia.org/wiki/Hammam
  6. Hannuksela & Ellaham, 2001: https://doi.org/10.1016/S0002-9343(00)00671-9
  7. Hunt et al., 2020: https://doi.org/10.3389/fphys.2019.01556
  8. Gryka et al., 2014: https://doi.org/10.2478/s13382-014-0281-9 
  9. Pilch et al., 2014: 10.5604/17342260.1133107 
  10. Laukkanen & Laukkanen, 2018: https://doi.org/10.1007/s10654-017-0335-y
  11.  Zychowska et al., 2018: https://doi.org/10.1155/2018/1685368 
  12. Kunutsor et al., 2022: https://doi.org/10.1007/s10654-022-00926-w 
  13. Leak, 2014: https://doi.org/10.1007/s12079-014-0243-9
  14. Krause et al., 2015: https://doi.org/10.1097/mco.0000000000000183
  15. Knekt et al., 2020: https://doi.org/10.1016/j.pmedr.2020.101221