I normally don't take Dr. Mercola's articles very seriously. In fact, I take his articles with a big pinch of salt.They suggest strongly that people don't have to lose muscle mass and function as they grow older.
The changes that we've assumed were due to aging and therefore were unstoppable seem actually to be caused by inactivity.
And that can be changed.
But this article is good. Read on, and let it motivate you to exercise regularly.