Adopting a sauna culture can reduce the risk of dementia and boost brain health

I’m already a dedicated cold water swimmer and last year I wrote about its benefits for the brain. But I started to see more and more written about heat therapy and his neurological benefits. And while the evidence is still emerging, it’s starting to look pretty compelling, so I decided to keep looking.

In terms of science, I made the most of Scandinavian sauna culture when I visited Finland and Sweden last month. I also learned that ‘sauna’ is pronounced ‘sow-na’ (with the ‘au’ rhyming with ‘how’) rather than my South East London ‘s’ pronunciationoron”.

The most studied are Finnish saunas, which are typically heated to 70 °C to 110 °C (158 °F to 230 °F) and have low humidity. Regular use is associated with many physical benefits – such as a lower risk of hypertension, muscle problems and respiratory problems. Now, however, scientists are beginning to uncover cognitive benefits as well. These improvements include fewer headaches, increased mental well-being, better sleep, and lower risk dementia.

In one of the largest studies I came across, nearly 14,000 people between the ages of 30 and 69 were asked about sauna use as part of a larger health study that was followed up 39 years later. After adjusting for other lifestyle factors, people who were more frequent sauna users—visiting a sauna nine to 12 times a month compared to fewer than four times a month— they had a 19 percent reduced risk of dementia until the end of the studies.

In addition to dementia, we have seen that sauna use is also associated with several other cognitive benefits. In one small study, 37 adults with chronic headaches were either given advice on how to manage their headaches or regularly visited a sauna and received the same advice for eight weeks. Those in the sauna-plus-education group showed a significant improvement in headache intensity. Regular sauna use was also associated with sa reduced risk of psychosisas well as an increasing vitality, your ability to live life in a way you personally value, and social functioning in older adults.

However, not all heat therapies are the same. While traditional saunas are the most common, there are other types of heat therapy with their own benefits. For example, in a small study, 26 people with major depressive disorder received one of them a single session of infrared heating of the whole body or fake treatment. Unlike traditional saunas, which use hot air to warm the body, infrared heating uses electromagnetic waves. The fake treatment looks and sounds the same, but the waves are not on. Those who received the actual treatment reported fewer symptoms over six weeks and showed changes in interleukin-6 signaling, a pathway involved in inflammation that is strongly linked to depression.

Why does heat therapy help the brain?

The anti-inflammatory effects of heat therapy appear to be key to its many benefits. In 2018, Setor Kunutsor of the University of Bristol in the UK and his colleagues analyzed the sauna habits and blood markers of inflammation in 2,269 middle-aged Finnish men who were followed for 11 years. After controlling for factors such as alcohol consumption and physical activity, the researchers found that frequent sauna use was associated with lower levels of several different inflammatory markers. The team concluded that the sauna’s health benefits may stem in part from reducing inflammation, as chronic inflammation is strongly associated with depression, cognitive decline and other neurological conditions.

Another possible mechanism is thermal shock. When your body temperature increases due to exercise or passive heating, triggers the production of heat shock proteins – molecules that act as chaperones for other proteins and ensure they don’t misfold or come together. These are critical because misfolded proteins are a hallmark of many neurological conditions. Last year, scientists have discovered more than 200 types of misfolded proteins in rat brains associated with dementia and age-related decline beyond familial amyloid and tau Alzheimer’s disease. This suggests that the protective effect of heat shock proteins may be a key part of the story.

Better blood circulation can also play a role. Heat causes blood vessels to dilate and improve cardiovascular functionblood pressure and arterial stiffness. Since reduced blood flow contributes to vascular dementia and Alzheimer’s disease, maintaining good cardiovascular health may indirectly benefit the brain.

Saunas can also increase the amount of brain-derived neurotrophic factor (BDNF) that circulates in the blood. These molecules act as fertilizer, helping neurons grow, and low levels are linked to depression and anxiety. In one study, 34 men were given either 12 or 24 sessions of infrared heating over 10 weeks or a low-intensity exercise regimen. Those who underwent repeated hyperthermia showed up significantly higher BDNF levels and showed better quality of life and lower anxiety than those assigned to moderate exercise.

Can saunas help you think better?

The potential long-term neurological benefits weren’t the only thing I was interested in. One small study of 16 men who had their brain activity recorded by EEG before and after sauna use suggests that it’s not just a short-term relaxation practice, but could also help us think more effectively. The participants’ brain wave activity more closely resembled a relaxed state after a sauna session, and although they did not perform any better on two tasks given shortly after leaving the sauna, their brain activity showed signs of greater efficiency in completing tasksindicating less effort for the same results. Scientists see heat therapy as a potential way to increase our ability to “sustain mental work capacity for longer periods of time.”

Of course, it’s not all good news. Most of us know that sluggish, foggy feeling that comes with too much sun and studying people exposed to heat of 50˚C (122˚F) for one hour back it up – exposure to this high level of heat changed the way areas of the brain communicated with each other, which was directly linked to slower reaction times. It’s there too some evidence that heat exposure can disrupt memory consolidationso maybe avoid saunas if you’re cramming for an exam.

If you are just starting out with heat therapy, British Sauna Society provides safety guidelines, including limiting your time in the sauna to acclimate to the heat, moving slowly and hydrating regularly, plus other tips to keep you safe.

Can a hot bath have the same effect?

What if you don’t live in a sauna-loving society or a trendy neighborhood blessed with pop-up sweat boxes? Can a hot bath work instead? Unfortunately, the jury is out. Hot baths can only partially mimic the benefits of a sauna, he says Ali Cadili at West Virginia University Medicine. They raise your core temperature, and repeated warm baths—30 minutes, five days a week for four weeks—have been shown to reduce resting heart rate and promote feelings of relaxation, which can improve mood. However, he says there is no direct comparison between a sauna and a hot bath. Cadili sees baths as a viable alternative to saunas if they are all available, but cautions that we need to keep in mind that there is more reliable long-term data linking saunas to dementia and stroke prevention.

With the cold water bathing and heat therapy I offer in my nearby lake – I wonder if combining the two might enhance the effects of both. Research is sparse, but I came across a study on what is known in Japan as totono state – intense feelings of happiness that people report after alternating hot sauna with cold water.

In the study, the participants alternated three times between a hot sauna, a stay in cold water and rest. Researchers measured brain activity before and after three cycles and found an increase in brain wave patterns associated with relaxation and reduced demands on attention.

It’s not yet clear if this is a better brain state than cold therapy or hot therapy alone, but overall it’s a lot more than I thought I’d get from sitting in a hot wooden box. So no, I don’t need another excuse to visit the lake or the spa, but it’s comforting to know that in addition to the immediate pleasure I get from such visits, a more regular sauna might just give my brain a cognitive boost, now and for the long haul.

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