I wish that point was stressed more often. So much of what's considered an inevitable consequence of aging is just related to unhealthy habits that can be avoided now. From smoking, to lack of exercise, to sitting in one place for too long. A healthy lifestyle doesn't make it a certainty that you'll be jogging at 80. It's just dramatically raising the chances of being happy and healthy into one's golden years.  But an unhealthy lifestyle does make it certain that you won't even have a chance at that kind of long, active, happy life.