Near Infrared vs Far Infrared Saunas: Which Wavelengths Do What?
Key Takeaways Near and far infrared are different wavelength ranges, not different strengths of the same thing. Lamp-based near-infrared saunas and far-infrared panel saunas differ in spectrum, radiant intensity, heater placement, and how heat is delivered. Near-infrared wavelengths fall within an optical window where light passes below the skin surface more readily than longer infrared wavelengths. Far-infrared energy is absorbed mostly by water in tissue near the surface. The heat it creates can then spread deeper by ordinary heat transfer. The widely repeated claim that far-infrared waves themselves penetrate 3 to 4 centimeters has now been tested directly. The measured effective thermal penetration was about 2.4 centimeters. A high-powered incandescent heat lamp delivers far more radiant and thermal energy than a small, low-output LED, although wavelength, not the type of source, governs how light interacts with tissue. Sauna heat of any kind raises skin blood flow, heart rate, and...