Rhonda Patrick is making a careful, calibrated argument here. Not "sauna is good for you" — she's been saying that for years. She's saying something more specific: of all the health risks she thinks about, dementia is the one that keeps her coming back to the hot room. Cardiovascular disease, she notes, is manageable. The causal pathways are well understood. Dementia is harder. Fewer levers. And sauna is one of them.
The headline number is the 66% reduction in dementia risk for people using the sauna four to seven times per week versus once weekly. That figure comes from the Finnish cohort studies — nearly 2,000 people tracked over decades. It's epidemiological, which means causation isn't certain. But Patrick's point is that the physiological mechanisms are real and well-documented enough that she's willing to act on the data.
Heat shock proteins are the underappreciated hero of this entire conversation. When you sit in a sauna at 163 degrees for 30 minutes, your HSP levels rise by 50 percent — and they stay elevated for up to 48 hours. These proteins are your cellular housekeeping crew. They find misfolded proteins — the kind that accumulate into plaques linked to neurodegeneration — and either refold them or tag them for disposal.
This isn't a marginal effect. This is biology doing exactly what it's designed to do, with heat as the signal. If you're using the sauna four times a week, you're essentially keeping this system running continuously. You're not waiting for problems to accumulate. You're clearing them before they compound.
Patrick is honest about what she doesn't know. Effect size from epidemiological data is genuinely hard to extract — healthy user bias is real, and the Finnish sauna culture involves lifestyle factors that don't isolate cleanly. What she's confident in is the direction of the effect and the plausibility of the mechanisms. That's a scientist being careful. It's also, in my view, the right posture.
The infrared versus traditional question is worth sitting with. Traditional saunas at 175 degrees drive heart rate up faster and more intensely. Infrared sessions at lower temperatures require longer exposure to achieve comparable cardiovascular load. Neither is wrong — they're different tools. But if you're optimizing for the Finnish study protocols, you want temperature. Actual heat. Not just mild warmth.
The safety note matters too. Above 200 degrees, some data suggests the risk curve inverts. More is not better once you cross that threshold. This is hormesis at work — the dose that builds resilience is not the dose that tests your limits.
Four times per week, 175 degrees, 20 minutes. That's the protocol the data supports. Hydrate before and after. Finish with cold if you have access to it — the oscillation between heat and cold amplifies cardiovascular adaptation and drives cortisol down more effectively than either alone. If you're doing contrast therapy, you're already ahead of the curve on this.
What struck me most in this conversation is the reframe Patrick offers around dementia prevention. We tend to think of brain health as a cognitive training problem — puzzles, learning new skills, staying mentally active. And those matter. But the cardiovascular pathway is arguably more powerful and far more neglected. Your brain runs on blood flow. Anything that makes your vasculature more flexible, more responsive, more resilient — sauna, exercise, contrast therapy — is directly protecting your cognitive future. The brain health benefits of sauna aren't separate from the cardiovascular benefits. They are the cardiovascular benefits, expressed upstream.