Dr. Bobby Deoy's framing here is useful precisely because it's so grounded. Not breathless promises, not biohacking theaterâjust a physician and Ironman triathlete making a quiet, evidence-based case that thermal stress belongs alongside nutrition, movement, sleep, and social connection as a foundational pillar of longevity. That framing matters. It removes thermal protocols from the fringe and places them in the center of a practical health conversation.
The core claim is straightforward: deliberate exposure to heat and cold, done consistently and without expensive equipment, produces measurable benefitsâreduced heart attack risk, improved mood, longer life. Fifteen to twenty minutes in a sauna. Three to five minutes in a cold environment. A few times a week. That's the protocol. Accessible to almost everyone.
The Finnish study he references is one I keep returning to. Twenty-five years of follow-up. People using saunas four to seven times a week had a 50% lower likelihood of developing high blood pressure. Not a modest reductionâhalf the risk, on one of the most powerful cardiovascular risk factors we know. That's not noise. That's a signal that deserves to be taken seriously.
It aligns precisely with what Rhonda Patrick has documented, and what the knowledge base reflects across multiple papers: repeated thermal stress is cardiovascular training. Your heart rate climbs, plasma volume expands, vasculature dilates and adapts. You're conditioning your circulatory system every time you sit in that hot room.
The cold side of the equation connects to something equally compelling. A 2015 study in the knowledge base found that cold acclimation significantly improved insulin sensitivityâmarkers of metabolic health shifting measurably after sustained cold exposure. Better glucose regulation, reduced inflammation, a more metabolically active body. Dr. Susanna Soberg's work echoes this: the discomfort of cold exposure is part of the mechanism, not something to minimize.
Deoy is appropriately skeptical about infrared saunas versus conventional ones. He's honest that the marketing has outrun the evidence. I appreciate that restraint. The Finnish dataâthe strongest longevity data we haveâwas collected in traditional high-heat saunas, not infrared. Either may work. But the burden of proof sits with the newer technology, not the other way around.
Treat thermal exposure like you treat exerciseâconsistent, dosed, and scheduled. Don't wait until you feel like it. Build the ritual. Two to four sauna sessions per week, 15-20 minutes, followed by a brief cold plunge or cold shower. The contrast amplifies the cardiovascular adaptation and adds a cortisol reset that compounds over time.
Deoy places this in historical contextâheat rituals in ancient Rome, Greece, Native American cultures, cold documented on Egyptian papyrus going back to 3500 BC. That lineage is worth pausing on. These weren't primitive practices replaced by better medicine. They were sophisticated stress adaptation protocols that modern science is now explaining. We didn't discover hormesis. We just finally gave it a name.