Consider the purported benefits of a post-workout ice bath, which is supposed to ward off inflammation and hasten muscle recovery.5 Athletes at every level swear by them; researchers, meanwhile, have published hundreds of studies investigating their effects, with results that are ambiguous at best. If you ask athletes how sore they feel the day after a workout, ice baths seem to help; if you take blood tests to look for objective signs of reduced muscle damage, not so much.
