You take your heart rate after sex, just to see if you hit aerobic. I took it right after one that was so intense I thought I was going to pass out - 96. I was really dissapointed. I'm sure my wife loved that....
or, if you were out on the track early christmas morning doing your proportional version of hiccam el g's workout.
i have started doing the same workouts that he does, only proportional to my ability. id say computing all of his training info and tapering it and doing the workout on xmas morning instead of opening presents, makes you a runner.