Exercise. Most of us hate it - I know I do, always have. But it doesn't have to be the stereo-typical stuff.
Exercise is anything that gets you moving, cardio is anything that ups your heart rate. And naked makes it more fun.
It can be as simple and easy as a walk in the park,
or a competitive game for fun with a bunch of friends.
Swimming is one of the best types of exercise there is because is uses every muscle you've got and gets the heart rate up
The idea is to enjoy whatever it is. That way it doesn't become a chore. Changing things up not only kills the monotony of it, it's useful for toning different muscles to keep the whole instrument in tune.
The more finely tuned the instrument,
the more joyous the music it makes.