I think people are looking way to deep into this: An old age with quality is what we are all after, the beautiful death: walking through the meadow at 90 on a glorious summers day and bang dead before you hit the floor... Perfect. Very rare though.
I think it comes down to good luck & bad luck. Friend of mine a couple of weeks ago aged 57, fit, ate paleo, never had a day off work sick. Triathlete, out on a training ride, dead, ran over by an arctic lorry, driver fell a sleep.
Another mutual friend obese, eats crap put coke up his nose weekly until he was 55, drinks copious amounts of alcohol, just turned 63. Most jovial man I know. Apart from the obesity he has no medical problems at all. Bp and all that, is all ok. Just don't figure:-(
Good luck - Bad luck, as simple as that. Do what you enjoy.