I spent 6 years in medical residency and fellowship. I never slept, never worked out, and ate and drank whenever I wasn't working. This of course is a bad recipe. I gained about 50 lbs and just realized I couldn't stand it anymore. I started working out with a Total Gym and a pair of 25lb dumbbells. Did about 45-60 mins a day 4-5 days a week for about 4 months until I was in decent enough shape that I felt comfortable going to the gym. About the same time, I started learning to play hockey and ice skate. I would either skate, practice, or play hockey and have been doing that for over 2 years now. This is my cardio. I hate running or bike machines - too damn boring. I have been seriously lifting for about a year now and work out about 5-6 days/week at a commercial gym. When I started exercising about 2 yrs ago, I weighed about 255 lbs and had no muscle. I lost about 50 lbs and have been building muscle for a while, and now weigh about 208 with a much different body composition.
I love being able to do hard things. Plain and simple. I don't feel embarrassed when I look in the mirror anymore, and there is nothing like throwing around a couple hundred pounds of iron to make you feel alive.