I have always argued that virtuous activities should give you more time, not less. So working out, sex, sleep, all should rewind time. When you get done it really ought to be the same time you started, or earlier, no matter how long you take.
At work we have a rule that whenever you come back from lunch, you left an hour before that. It doesn't matter how long the lunch actually was. You could have a two hour lunch, that is a one hour clock out.