Ever get so mad you could just… run a mile? Anger can be fiery fuel for a serious sweat session — and that exercise, in turn, can help blow off some steam, culminating in both a serotonin rush and a freeing release of tension. That’s the idea behind rage workouts, which fans say do double duty to keep both your mental health and muscles in shape. People are doing “rage workouts,” where they don’t just exercise — they work through their anger. Kim Day Training Pummeling a punching bag just hits different For Patricia Paden, the Rage Room HIIT class at Kim Day Training in Knoxville, Tennessee is a must for channeling anger. “Somehow, you always feel lighter when you leave,” she told The Post.…