Well, I usually do exercises from different workout programs, specifically P90X and Insanity. P90X workouts range from 15 min (Ab Ripper X) to 57 min (Core Synergistics). Insanity (which I just started) doesn’t seem to have workouts longer than 40 some minutes. 

But when I run, I run for at least an hour. I’m an awfully slow runner! But I’ve come to accept that it’s okay since I’m pacing myself and since that’s always been difficult for me, it’s a good challenge.