Yeah, it pays to be a little careful too. When I was young a friend that was only two years older than me was baling hay all day on a very hot day and then walked out to the end of the dock and dove into the lake to cool off. It killed him.Many moons ago, before lawyers ruined everything as they always do, my gym had a real steam room and a cold plunge - a tank of 55 degree or so water just big enough and deep enough for one person to totally immerse themselves
It was exhilarating to go right from the steam room to cold plunge and then back to steam as quickly as possible and seemed to reduce post workout muscle aches if repeated several times
I can't imagine what it does to your blood pressure upon entry into the cold plunge, though
We learned about taking salt pills in high school football but that was too late for him, maybe it would have helped.