Lift those legs and invigorate those cells.
As you age, your muscle cells gradually start to weaken and go dormant. This is why it’s harder for older folks to maintain muscle mass, and why they become more susceptible to severe injuries and illnesses. Luckily, consistent exercise has been proven to slow this process, keeping cells stimulated and preventing them from going dormant. However, according to a recent study, we might not have to stop at merely slowing the process down. Certain kinds of exercise could actually reverse the aging of muscle cells, restoring them to their youthful forms.
This is still highly experimental, so take it with a pinch of salt. Researchers assembled several groups of lab mice and had them engage strictly in aerobic exercise. No strength, no weights, just aerobics. What they found is that, in the older mice who exercised regularly, injuries healed much quicker and muscle mass was built more easily. To verify this, muscle cells from the older mice who exercised were transplanted into younger control mice, and the stimulated cells performed almost identically to the naturally youthful cells. What this means is that, through a regimen of regular aerobic exercise, you could, in theory, get your body feeling like it was in your prime. Healthier, stimulated cells means more muscle mass and increased resistance to injury and disease.
Further research is still needed, and the process needs to be tried on human subjects. Nevertheless, as previously mentioned, aerobic exercise is confirmed to at least slow the aging process, so you should start lifting those knees sooner rather than later. Go jogging, try dancing, or swim laps. Worst case scenario, you take a little longer to start sagging. Best case scenario, you never sag at all. I’d call that a win-win.