I work out 3-4 times a week. Hit the weights about twice a week for upper body and I run the rest of the time. I have also recently gotten into participating in half-marathons. Completed one and need to sign up for the one coming up. I also have a low calorie diet I follow of just random foods I like that are filling. People need to realize that working out isn't enough, you need to have a nice diet to go with the the work out. Dieting is the most important part to staying healthy.
It is important to keep not just in shape but actually have some strength with that endurance. I like a good balance.
Plus the military helps with that.