Minutes 0–5 · Skin
The surface flushes first
Heat reaches your skin before anything else. To shed it, the blood vessels just under the surface widen and more of your blood is sent outward — that is the flush you see.
With those vessels open, blood pressure eases. In a controlled trial, 30 minutes at 73°C lowered systolic pressure by 16 mmHg and diastolic by 5 mmHg on average.
−16 mmHg average drop in systolic pressure

































