Loading…
Story
regulates · 2
In the heat, skin blood vessels widen and the heart pumps out more blood, so the drag of blood along the vessel lining rises and the lining cells release nitric oxide, which lets the vessels relax more easily. After several weeks of repeated heat, flow-mediated dilation, a measure of how well the lining works, improves somewhat; this chain is the leading candidate explanation for how heat therapy improves blood-vessel function, and the effect is modest.
In an analysis pooling 15 heat-therapy studies, several weeks of repeated heat lowered systolic and diastolic blood pressure by about 3.9 mmHg each on average. The studies covered not only sauna but also hot-water immersion; the effect is modest, and it is evidence of blood-vessel adaptation, not a prescription to treat high blood pressure with a sauna. People who already have high blood pressure should still follow their doctor.