Many people strive to retire to Florida, just to enjoy their free time in warm and sunny weather. But a new study links vitamin D, the sunshine vitamin, to muscle strength among seniors. In fact, if you don't have enough of it in your blood, chances are, just rising out of your favorite easy chair isn't as easy as it used to be.

By now, you probably know that vitamin D is essential to maintaining good health. But can it really make you stronger? Yes, it can! You see biochemists have long known that vitamin D is essential to muscle development. Without it, your tissues tend to accumulate fat instead of building muscle.

To build on this theory, scientists from Wake Forest University recruited 3,000 men and women over the age of 75 to take part in a new study. They chose this age group because these folks – by and large – tend to be deficient in vitamin D. So to get things started, the Wake scientists tested each of the participants' blood for vitamin D. Then, they gave each of the seniors three simple physical tests. For the first test, they asked the seniors to rise quickly from a chair five times. Then, they asked them to walk six meters (about 18 feet) as fast as they could. And lastly, they measured how well the seniors could maintain their balance in a challenging position, such as standing on one foot.

Not surprisingly, those with the highest levels of vitamin D levels scored excellent marks on all three of the physical tests. On the other hand, of the seniors who scored lowest on the physical tests, 90 percent of them had deficient levels of vitamin D.

These findings back up another similar study from 2003, where men and women with low vitamin D were 2.5 times more likely to suffer from sarcopenia (age-related muscle loss).

So the take-home message today is to boost your vitamin D, especially if you're in your golden years. It just may help you keep up with the grandkids! And now that good weather has reached most of the country, aim to spend 20-30 minutes outside in the sunshine without sunscreen each day. And once the winter months are back (or if you live in the northern half of the country), take up to 5,000 IU of vitamin D each day.