A fixed mindset would be correct I’m pretty sure
Answer:
being free of disease is part of being well cause when you free you can do other things ☺
I would go with "Exercise regularly to keep his heart and muscles healthy and strong". A person who cares about their health would not avoid going to the doctor's or stay up very late at night, nor would they eat a well-balanced diet only so they can look good or attractive.
Hope this helps! :D
