Cold is good for shocking the body, and reducing swelling. Heat is good for blood circulation, and keeping your body within its preferred temperature. Loosens up your pores and gets that old flem moving out you lungs and Best time to get your morning stretches in, too. So long as you don't fall. I walk away from a hot shower ready to go limber af, and focused. I'll take the latter. Cold is much harder on your heart, old man.