So how addictive is exercise exactly? If you're exercising, past the point where you feel physical hurt, because it makes you feel immediately more alert (or straight up euphoric depending), is it dangerous? It's usually attested that too much of one specific kind of exercise (e.g. running) can have problems for certain muscles and joints but I'm not finding a lot on the dangers (if any) of more diverse exercise (where you keep moving with elevated heart rate for a long, sustained, time period, but don't do the same movements every day or every hour in a single day).