Dr. Sean O'Mara is making two arguments here, and it's worth separating them. The first — that traditional dry finish saunas have extraordinary, research-backed health benefits — is rock solid. The second — that infrared saunas are potentially harmful because the deeper-penetrating wavelengths bypass our evolutionary adaptation — is theoretically interesting but much less established.
The Finnish epidemiological data he's drawing from is some of the strongest evidence in the entire wellness space. Nearly 2,300 men tracked for over 20 years. Four to seven sessions per week cuts all-cause mortality by more than half. Dementia risk drops by 65%. These aren't small effects from a small study. This is longitudinal data at a scale that most pharmaceutical trials would envy.
On traditional sauna, O'Mara is in lockstep with Rhonda Patrick, Andrew Huberman, and the Finnish research teams behind the KIHD study. The cardiovascular mimicry argument is well-supported: heart rate climbing to 100-150 beats per minute, increased plasma volume, improved vascular compliance. You're training your circulatory system without running a step. The heat shock protein mechanism — clearing misfolded proteins before they aggregate into plaques — is increasingly accepted as a core pathway for the dementia prevention data.
But on infrared? The "evolutionary mismatch" argument is O'Mara's own theoretical framework, not peer-reviewed consensus. Near-infrared and far-infrared saunas do penetrate differently than ambient heat, but there's no established body of evidence showing harm. Most researchers simply note that infrared saunas operate at lower temperatures, which means a weaker cardiovascular and hormetic stimulus — and therefore, less benefit. The absence of benefit isn't the same as risk.
The honest position is this: O'Mara's concern about infrared is speculative. His recommendation to use traditional dry finish saunas is excellent. Conflating the two — implying infrared is dangerous — goes further than the evidence supports. Most researchers who study sauna simply observe that infrared is the lower-evidence option, not the harmful one.
If you're choosing between modalities: traditional dry finish sauna, 175 to 190 degrees Fahrenheit, 20 minutes per session, four times per week. That's the protocol with decades of data behind it. If you already have an infrared unit, you're probably not harming yourself — but you may be getting a diluted version of the benefit. The temperature matters. The heat shock response requires adequate thermal stress.
O'Mara's critique of the healthcare system lands harder than his infrared argument. Chronic disease is the largest sector of the global economy. Practices that demonstrably reduce all-cause mortality by 50% don't move through medical culture quickly — not because physicians are malicious, but because the system is organized around treatment, not prevention. Sauna therapy costs nothing to prescribe. That's both its strength and why it struggles to get traction. The most powerful health interventions are often the ones with no economic engine behind them.