Sauna 4–7 times a week — not once. In a 20-year study of 2,315 middle-aged men, those who used a sauna 4–7 times a week had 40% lower all-cause mortality and 50% lower fatal cardiovascular disease than once-a-week users (Laukkanen et al., JAMA Internal Medicine, 2015). The benefit tracked with frequency — which is the whole argument for owning a sauna instead of booking one. And frequency only happens if the session is worth repeating: Peak pairs true full-spectrum infrared — near, mid, and far wavelengths — with a medical-grade, full-body red-light suzilve, in a cabin that preheats from your phone before you walk in.