Let’s say you’ve been a slug much of your life and have never enjoyed exercise, not so much as a stroll around the block. Now that you’ve reached your golden years, why bother? The damage to your health is done, right?

Not so fast — it’s never too late to put on a pair of sneakers.

A recent study by researchers around the nation, including several at the University of Florida’s Institute on Aging, has found that just 48 minutes of walking or other exercise a week — roughly seven minutes a day — can dramatically reduce disability risk in the elderly. And it can lead to meaningful improvements in physical functioning.

In fact, researchers said, the more exercise, the better.

In a paper published in the online journal, PLOS One, researchers followed more than sixteen-hundred sedentary men and women ages 70 to 89 with physical limitations and tracked them for more than two-and-a-half years. One half received health education. The other half participated in a structured walking, resistance and flexibility program.  The physical activity of both groups was logged.

The main finding of the study? Increased physical activity improved physical function over a two-year period and reduced the onset of major mobility disability.

Of course, doctors say exercise is always a good idea no matter how old you are. Regular physical activity is associated with reduced mortality and risk of physical disability. It improves your mood, doctors say, and it keeps the waist trim, among many benefits.

In addition, if you start young, you stay young.

In other words, don’t take this study as an invitation to sit on your duff until you hit old age.