Connie Zack makes a distinction that most people miss when they first encounter infrared: this isn't heat therapy. It's light therapy that produces heat as a byproduct. "Infrared is more like energy medicine versus heat medicine." That's not marketing language. That's a meaningful mechanistic claim. Traditional sauna heats the air, which heats your skin, which eventually heats your core. Infrared bypasses that chain — the photons penetrate tissue directly, agitating water molecules inside cells and increasing circulation from the inside out. Three times the blood flow, instantly. That's a different mechanism entirely.
The Finnish sauna research that Rhonda Patrick has spent years translating — nearly 1,700 participants, dose-dependent cardiovascular benefits, 50% reduction in cardiovascular mortality at four to seven sessions per week — was done in traditional convection saunas. The air gets hot. You get hot. The cardiovascular mimicry of exercise follows. What Zack is describing here operates through a different pathway, though it converges on many of the same outcomes: improved circulation, mitochondrial support, heat shock protein activation, reduced inflammation.
The heat shock protein mechanism is worth dwelling on. When infrared energy agitates cellular water and raises tissue temperature, your cells respond the same way they would to any thermal stress — they produce chaperone proteins that refold misfolded proteins or tag them for clearance. Misfolded protein aggregation is central to neurodegeneration. Keeping that housekeeping process active is one of the most compelling arguments for regular heat exposure of any kind, traditional or infrared.
Experts broadly agree on the vascular and mitochondrial benefits. Where disagreement emerges is in the gender data on cold therapy, which Zack mentions briefly and deserves more attention than it gets. The research suggests that cold exposure improves heart rate variability, resting heart rate, and sleep for men — but that same night, women often sleep worse after cold exposure. This isn't settled science, but it's a signal worth taking seriously. For contrast therapy protocols specifically, the cold component may need to be dosed differently based on sex, timing, and hormonal context. Infrared, by contrast, appears to benefit both sexes without the same disruption pattern.
If you have access to both traditional sauna and infrared, they aren't interchangeable — they're complementary. Traditional sauna excels at cardiovascular conditioning and growth hormone stimulation at higher temperatures. Infrared excels at deeper tissue penetration, gentler heat load, and the specific photobiomodulation effects on mitochondria. For recovery days, for people who run hot, or for those who find high-temperature sauna difficult to tolerate, infrared is the more accessible entry point. Twenty to thirty minutes, three to five times per week, is where the research points.
Zack mentions mental clarity — "any type of mind chatter goes away" — and attributes it to increased cerebral blood flow. That's probably part of it. But there's another mechanism worth considering: the mild hyperthermia from infrared exposure triggers the same endorphin-dynorphin cascade that traditional sauna does. Short-term discomfort, kappa opioid receptor activation, and then a sensitized mu opioid system afterward. You feel clearer not just because your brain is getting more blood. You feel clearer because your endogenous opioid system has been primed. The calm that follows an infrared session isn't passive. It's your nervous system recalibrating after a productive stressor. That's a different story than "I sat in a warm room and relaxed."