Certainly healthier than not doing it! "Healthy" in the context you've used is not a binary state. "If I do X it is healthy, therefore I will do X and I don't

Certainly healthier than not doing it! "Healthy" in the context you've used is not a binary state. "If I do X it is healthy, therefore I will do X and I don't have to do anything else". Unfortunately it doesn't work like that. It's more like a curve and it's not just one thing. So you can be super fit training for marathons, but honestly you need some excess muscle mass because you're going to start losing it when you are 50-60 years old. You need to make sure that you are flexible because when you get older, if you aren't flexible you won't be able to balance and walk, etc. It's best to start training early so that it's easier to maintain that flexibility. Even if you are running marathons and staying trim, if you eat junk you can die of lots of different conditions. So endurance training, strength training, flexibility training, and diet all work together to help your health. At the same time, there are lots of ranges of activity where you will be just fine as you age and there are ranges of activity at both ends (sedentary and over training) where you won't be fine (although it's a heck of a lot harder to over train that to be sedentary ;-) ). Finally, there is something to be said for not overdoing things at a start. So while you might want to have this amazing training regimen someday, it would be a bad idea to start out tomorrow and do it -- you want to slowly work your way up to it. So the answer you are probably looking for is "No, it's probably not sufficient to keep you fit and healthy for your whole life". But it's certainly a great start -- especially if it gets you doing other things that you might not have tried before. And it doesn't have to be training -- it can be playing soccer with a local league, or cycling with your friends or any number of social and pleasant activities. How much is enough? Try to keep your weight, muscle mass, endurance and flexibility a fair bit more than what you actually need so that you can afford to lose some. Eat a diet that makes you feel good and consult with doctors when you have health problems. It's hard to say exactly what that will entail, because it is different for everybody.