These comments are spot-on as far as physical health is concerned. Make an effort and you'll significantly improve your quality of life. I'd say you don't necessarily need to run marathons or triathlons, though, and I'd also suggest that cardio is not the best way to maintain good health, strength training is better.

I have been lifting weights for years now, and it does wonders for my health (for example: all my back pain and back injury problems are totally gone).