Does he have the Active trait? My Active sims are always wanting to exercise. If they own exercise equipment, they will use it frequently. If they do not then they have been known to go jogging autonomously. This gets more intense if they have the Athletic aspiration, and the more fit they get the more they want to exercise.
This is a good thing if they are in the athletic career track because they will often complete their after-work requirement while I am busy with my other sims in the household. It is also good for their moods as Active sims will get extremely tense and unhappy if they don’t exercise every day. They also appear to learn; if you encourage them to jog they will do it more autonomously but if you encourage them to use the treadmill, then they will prefer it. I have also noticed that my Sulani sims who are Active seem to want to swim.
If your sim doesn’t have the Active trait, is he energized when he jogs? Sims (even kids) who are energized will autonomously exercise, although mostly they do simple things like push-ups. A sim with higher fitness will sometimes choose to jog, though. Lazy sims never exercise, and if you make them they will be miserable for a long time.
By the way, the same sort of thing happens to Creative sims. A creative sim who has been using an easel previously will often autonomously choose to do so, especially when feeling inspired or bored. But if you encourage a creative sim to play the guitar or piano, then the sim will choose an instrument instead of an easel. Aspirations increase this tendency but you can also shift it over time by getting them to use different objects. I like the feature— it works well with compatible careers and makes the sims seem more like individuals.
