Crossfit 4 to 5 times a week. Crossfit is one of the best exercise regiments that I have found for a busy lifestyle. You go 4 to 5 hours a week, learn some great skills, you are a part of a great community and you stay healthy. I credit Crossfit for getting back to a healthy weight, becoming stronger and keeping sickness at bay. Whichever type of exercise you choose I think consistency is key. Keep doing it, make it a habit you can't beat.