You read correctly, it's not impossible to get healthier, stronger and even quicker as we get older (it does depend on how quick you were to start with, Usain Bolt probaly won't get quicker with age but I do know competitive club runners who have got pb's well into their 60's).
The truth is, a lot of us associate increasing age with declining health. Once you're over 50, creaky bones and shortness of breath become the norm right? The longer I work in sports medicine and the more involved I become in research, the more I realise that although increasing age undoubtedly does lead to decreased health for the majority of the population, that doesn't have to be the case.
Indeed, I'd go so far as to describe it as a choice. If you choose to actively make positive choices in terms of exercise, diet, rest and managing stress then there's no reason you can't still be running and lifting weights as you get into your twighlight years. I have several clients who are lifting heavier weights and running quicker 5k's in their 60's than they were in their 20's (I should add that how much you can lift and how quick you can run aren't necessarily that important, but they can be a helpful indicator).
No one's saying it's easy to make the necessary lifestyle choices and it's vital to be motivated and be aware of how life-changing this can be. I'm not saying it's simple, it's not just a case of doing parkrun or yoga once a week. I'm not even saying its guaranteed, some people will do everything right and still end up with an auto-immune condition, osteoarthritis or a premature heart attack...BUT making ghe right lifestyle choices will minimise the risk and severity of these conditions and more.
The research is clear. On balance if you make the correct lifestyle choices your body is much more likely to stay strong and healthy into old age. Correct lifestyle choices sounds simple and in many way it is but it's not just one thing. It's not just a case of doing parkrun once a week or going to an occasional yoga class. It should be a concerted effort on a variety of fronts. Exercise is number one, that can be cardio such as running whihc has dpozwens of benefits including improved heart function, strength training (such as lifting weights) which helps strengthen the muscles, bones and joints, reducing the risk of arthritis or breaking a bone when you fall. Regular stretching (such as yoga) is helpful in a number of ways but on a basic level it loosens the muscles and tendons and means you are less likely to get injured doing strength training.
We don't have space to cover every aspect of aging with grace but recovery is just as important as the exercising, there's little point in putting all the hard work in if you then don't replenish the body with good food and rest....