I think the use of the term "aging" in the article is misleading. We all know that if you want to maintain a certain level of fitness, you must keep working at it. If you stop, you will regress in muscle strength, muscle memory (which can affect balance) and endurance. I had the physiotherapist tell me yesterday my grip strength is greater than many younger men. I suspect they're not splitting and carrying wood, shingling, fencing and maintaining a property.
If my activities were centered around tapping a keyboard all day and lifting nothing heavier than a file folder, I might be built like my SIL's husband. He is 20 years younger than I, but is in seriously poor physical condition.
But aging? Unless he gets fit, I suspect I will make a better looking corpse.
I've known some guys who were in fantastic shape, right up until the time their time was up from heart attacks.
Best
Les