its working well for me at 44 years of age.
You're only 44, mate; it's nothing these days. 40 years ago, asbestosis, miner's Pneumoconiosis, or just plain old smoking would've meant you're almost dead; but now 40 is the new 25, mate.
Wor Lass is nearly your age and she's running 60 to 70 miles a week and doing Insanity workouts on top of that. In two weeks she's doing a 12 hour running event (running for 12 hours non-stop) and in July she's doing the same, but for 24 hours; she expects to do at least 100 miles on that event; hopefully 120 miles.
I think she's the fittest window cleaner I know!
But my, if she works past 3.00 pm, she gets all narky and her nose starts bleeding.
Me? I do the odd parkrun.