text: is it unhealthy to exercise twice per day? i joined a gym two days ago and have been going morning and night. i would like to continue, but dont know if it is unhealthy for your muscles to exercise 2 times per day. i want to loose 25 pounds asap!! yes! it is very healthy to exercise twice a day, but haow long do you exercise? the doctors tell you that you should exercise atleast 30mins. a day every day. and that it is good for your heart and bones.