I'm 44, and in better shape than I've been in for years. I've lost 20-25 pounds in the last 4 years, and I can really tell it when climbing. I do 55's now and then...10 push-ups, then 1 squat...9 push-ups, then 2 squats.....and so on til you reach 1 push-up and 10 squats. It'll get the cardio...