Hot Works is arguing that combining infrared heat with exercise creates a more efficient workoutâfaster heart rate elevation, greater calorie burn, better metabolic adaptationâall in the same session. They're calling it "3D training." Strip away the franchise language and the Super Bowl aspirations, and there's a legitimate physiological idea underneath it.
The question worth asking is whether they've correctly identified the mechanism, or whether the marketing has gotten ahead of the science.
The cardiovascular response to heat is well-documented. When you raise ambient temperature, your heart rate climbs to dissipate heat through increased blood flow to the skin. Add exercise on top of that, and your heart is now managing two competing demandsâworking muscles and skin coolingâsimultaneously. Your cardiovascular system has to work harder. In that sense, yes, you're getting more cardiac stimulus per unit of time.
Rhonda Patrick's work on Finnish sauna dataâthose large cohort studies showing 50% reductions in cardiovascular mortality at four to seven sessions per weekâis built on passive heat exposure, not exercise in heat. The two are related but not identical. When you're exercising in an infrared environment, you're stacking stressors. That can amplify adaptation signals. It can also accelerate dehydration and push people into overexertion faster than they realize, because perceived effort in heat doesn't always match actual physiological load.
The infrared piece specifically matters here. Unlike traditional dry saunas or steam rooms, infrared energy penetrates tissue rather than just heating the air around you. The core temperature response can be more pronounced, and heat shock protein activationâthose molecular chaperones that refold misfolded proteins and clear cellular debrisâcan be triggered at lower ambient temperatures than traditional sauna requires.
The "more workout in less time" framing is where things get slippery. You're burning more calories in a heated environment, yes. But some of that burn is thermoregulatoryâyour body working to stay coolânot muscular. Whether that translates to the same strength or endurance adaptations as a conventional workout is less clear. The isometric focus is interestingâholding postures in heat while your core temperature climbs requires genuine stability and concentration. But it's a different training stimulus than progressive overload, and the long-term strength outcomes would need more data.
The psychological piece is real though. Members report feeling invigorated, focused, cleaner somehow. That's not woo-wooâit's the post-heat dopamine and endorphin response, the same mechanism that makes sauna use a legitimate mood intervention in depression research.
If you're drawn to infrared fitness studios, go in with realistic expectations. The cardiovascular and metabolic benefits are genuineâheat adaptation is a real signal, and the efficiency gains are measurable. But start at lower intensity than you would in a conventional gym. Your heart is already working harder before you lift a weight. Hydrate aggressively before and after. And if you're already doing traditional sauna, recognize that infrared exercise is cumulative thermal loadânot a replacement for recovery protocols, an addition to them.
What strikes me about the Hot Works model is that it's essentially industrialized hormesis. Most of us think about contrast therapy, cold plunges, and sauna as individual protocolsâdiscrete stressors we apply sequentially. Hot Works is arguing for simultaneous stressor stacking, exercise layered on top of infrared heat, as a single compound signal. The adaptation that produces may be distinct from either in isolation. That's genuinely interesting. We don't yet have long-term data on what compound hormetic protocols do to recovery timelines, inflammation markers, or musculoskeletal resilience. But the hypothesis is sound. Your body doesn't adapt to individual inputs in isolationâit adapts to the full environment it's placed in. Hot Works has built an environment designed from the ground up to be that stressor. The franchise ambition may be loud, but the underlying biology is worth taking seriously.