Can Sauna Use Protect Against Alzheimer's?

What 16,000 Finns Tracked for Decades Reveal About Heat and Brain Health

Photo by HUUM on Unsplash

Finnish researchers following over 16,000 people for decades have uncovered an intriguing pattern: regular sauna users develop dementia at significantly lower rates than those who rarely use them.

Here's what the evidence shows and why it may not just be correlation.

The Evidence

The data comes from Finland, where sauna use is deeply embedded in the culture, giving researchers a unique opportunity to study its long-term health effects across large populations.

Two landmark Finnish studies have tracked this relationship between sauna use and cognitive decline, following participants for decades to understand potential protective effects.

The Kuopio Study (2,315 men tracked for 20+ years)

• Men using saunas 4-7 times weekly: 65% lower risk of developing Alzheimer's

• Those using saunas 2-3 times weekly: 20% lower risk

• Benefits remained after adjusting for age, alcohol use, weight, blood pressure, and smoking

• Suggests the protective effect isn't just from living a generally healthy lifestyle

The Finnish Mobile Clinic Study (14,000 people followed for 39 years)

• Optimal frequency: 9-12 sauna sessions per month reduced dementia risk by 21%

• Best temperature range: 80-99°C (176-210°F)

• Sessions lasting 5-14 minutes showed the strongest benefits

• Higher temperatures (100°C+) actually increased risk, indicating there's a therapeutic window

The consistency across both studies - involving over 16,000 people tracked for decades - suggests this isn't a statistical fluke.

But correlation, even strong correlation, doesn't prove causation. To move beyond correlation, we need to understand the biological machinery at work.

How Might Heat Protect the Brain?

Population studies show the 'what' - but understanding the 'why' means diving into the biology. A remarkable case published in Nature Medicine in 2025 provides a window into a possible mechanism.

In this study researchers studied a man carrying a genetic mutation (presenilin 2) that typically causes Alzheimer's in one's 50s - yet he remained cognitively intact decades beyond that point.

The unusual factor? He'd worked for years in a ship's diesel engine room, exposed to extreme heat on a near daily basis.

Importantly when researchers examined his brain, they found abnormally high levels of heat shock proteins - molecular chaperones that help other proteins maintain their proper shape and prevent the toxic protein clumping that characterises Alzheimer's disease.

This single case can't prove heat saved him from his genetic fate, but when combined with the population data, a compelling biological story emerges.

Other Reasons It Might Work

Of course, heat exposure likely protects the brain through multiple pathways beyond just heat shock proteins. This is because regular heat exposure also triggers repair and maintenance systems throughout your body:

• Improved blood vessel function

• Reduced inflammation throughout the body

• Improved blood pressure, reducing strain on small brain vessels

Practical Guidelines

If you're interested in trying sauna bathing, here would be my approach based on the two Finnish studies conducted: