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Heather Hausenblas, associate professor of kinesiology in the Jacksonville University College of Health Sciences

We may live in the Sunshine State, but are we getting enough of the sunshine vitamin, better known as vitamin D?

Research published in the Journal of the American Medical Association reveals that about three out of four U.S. teens and adults, including Floridians, are deficient in this essential nutrient.

While studies continue to refine how much vitamin D we need, most Americans are vitamin D deficient, which may lead to health risks beyond poor bone development and osteoporosis. Emerging research is revealing that low levels of vitamin D may be related to, if not a cause of, heart disease, certain cancers, depression and high blood pressure.

Although vitamin D is obtained from our diet and dietary supplements, the main source of vitamin D is from the sun. But we have all heard that too much sun is bad for us.

A study published in the International Journal of Epidemiology found that more lives are lost to diseases caused by a lack of sunlight than to those caused by too much sun exposure.

The researchers concluded that sun protection messages are important to prevent diseases of sun exposure, but that without high dietary or supplemental intake of vitamin D, some sun exposure is needed to avoid vitamin D insufficiency.

But just how much sun do we need?

Because so many factors influence the rate of vitamin D formation in our skin, it is difficult to establish a universal public health recommendation for sun exposure.

A common expert recommendation is to get regular, non-burning sun exposure. This means going outside during the middle hours of the day when the sun is at its highest for about 15 minutes three times weekly.

And if you want your skin to absorb the sun’s rays, you can’t wear sunscreen. Studies have found that sunscreen with sun protection factor of 8 or higher blocks our skin’s ability to produce vitamin D from sunlight by as much as 95 percent.

Vitamin D gives us another reason to get outside and enjoy the sun. Remember to not overdo your time in the sun: burning and excessive exposure will increase your risk of certain skin-related diseases. Cover up or apply sunscreen after your initial vitamin D-boosting burst.


Can physical activity help kids think better?

Here is another reason to get your kids unplugged and outside playing: It will help them think better. In a recent paper published in the journal Pediatrics, researchers found that kids who did an hour a day of physical activity were better able to pay attention, avoid distractions and switch between tasks (multi-task) than kids who did not move as much. And the physical activity the kids were doing was running around and playing tag, soccer, jump rope and other games. The focus was not on competition, but rather kids just going outside and playing.

Fit Life, by fitness and healthy aging expert Heather Hausenblas, associate professor of kinesiology in the Jacksonville University College of Health Sciences, appears the first Monday of each month in the Outside section of The Florida Times-Union. E-mail your questions to hhausen@ju.edu. For more on JU’s Department of Kinesiology, visit http://ju.edu/chs.