Is using a sauna regularly beneficial for my vascular system?

KLAFS FAQ for well-being

The heat of the sauna stimulates your vegetative nervous system, whilst cold water in the cooling phase causes your blood vessels to retract again. The cold stimulus makes your expanded blood vessels contract suddenly to prevent them from losing any more heat. This “trains” your blood vessels in a highly effective manner – particularly your veins, which don’t otherwise have much opportunity for such exercise.