Wearing pajamas to the gym is problematic, giving people an indecent and uncivilized performance. The gym is a place to exercise, not sleep, so it is more appropriate to wear ordinary clothes or fitness clothes in the gym. If you run a gym at home and there is no one else in the gym, you can wear whatever you want. If there are others, it is best not to wear pajamas, which will attract others' strange eyes and make you feel a little embarrassed. A gym is a place to exercise. Don't go to the gym or wear pajamas unless you exercise.