It's no secret that physical activity is a key part of keeping kids healthy, but two new studies add hard evidence to what seems to be common sense: exercising in school has an important impact on students' health.

One study of kindergarteners to fifth graders across the U.S. found that physical education (PE) classes lowered body mass index (BMI) scores and reduced the probability of obesity among fifth graders. An additional hour of gym time lowered BMI for all children in the study by 0.5.

Although the U.S. Centers for Disease Control and Prevention (CDC), the American Academy of Pediatrics and other major groups have previously urged regular school PE time as a method for fighting childhood obesity, this study provides some of the first evidence of a causal link between gym classes and weight in elementary schools.

"The hope with physical education is that it influences behavior in school, but also out of school," leading to an overall more active lifestyle, said David Frisvold, Ph.D., assistant professor of economics at Emory University and one of the study's authors.

That may have been the case for the boys in the study, the authors said. The results showed that PE's effect on lowering BMI was especially true for boys, and Frisvold and his colleagues suggest that the difference is because PE is often a complement to additional physical activities, like sports teams, for boys. Girls more often use PE as a substitute for other physical activity.

The researchers studied data on schoolchildren in kindergarten through fifth grade collected by the U.S. Department of Education, including height, weight and how much time they spent each week in PE, a factor largely influenced by state laws.

Staff of the North Georgia Health District welcome John "Jack" Kennedy, M.D., MBA, as the district's interim health director.

Kennedy replaces Harold Pitts, M.D., who had served in that position since 2005. Kennedy is the director of the Cobb & Douglas Public Health District and will concurrently provide interim leadership of the North Georgia Health District until a permanent health director is named.

"I am excited about getting to know everyone so we can pursue our public health mission together," said Kennedy. "I appreciate the warm welcome I have received here."

Born in Providence, R.I., and reared in Richmond, Va., Kennedy practiced general surgery in the United States Air Force and, subsequently, in Marietta for 26 years where he also served as the founding board chairman of the Good Samaritan Health Center of Cobb. Presently, in addition to directing the Cobb & Douglas Public Health District, Kennedy serves as an affiliated professor in the Office of Applied Public Health at Rollins School of Public Health, part of the Woodruff Health Sciences Center of Emory University.

Kennedy is a graduate of Duke University where he received both his Bachelor of Arts in chemistry and his medical degree. He received an MBA from the Michael Coles School of Business at Kennesaw State University. Kennedy completed his surgical internship and surgical residency at Emory University Affiliated Hospitals.

Do you know what SPF stands for? What about that number that follows it? Does sunscreen really stay on after a dip in the pool?

The U.S. Food and Drug Administration (FDA) is hoping to clear up some of this confusion with new rules for manufacturers on sunscreen labeling, aiming to help consumers protect their skin with the right sunscreen, which experts say too few people use adequately.

Protecting the skin is crucial for preventing skin cancer, the most common kind of cancer in the U.S. About 1 million Americans get skin cancer each year, including basal cell carcinoma, squamous cell carcinoma and melanoma, the most serious kind of skin cancer.

From 2006 to 2010, nearly 9,650 Georgians had melanoma and nearly 1,000 died from it between 2004 and 2008. Although people with lighter skin tones are at greater risk, people with darker skin can get skin cancer as well. It's important for everyone to know how to protect skin, starting with using sunscreen correctly.

The FDA now urges all consumers to use broad-spectrum sunscreen, meaning that the product protects skin from two types of cancer-causing sun rays: UVA rays, which age the skin, and UVB rays, which burn the skin. The agency also said sunscreen should have an SPF, or sun protection factor, between 15 and 50, noting that there is no evidence that SPFs above 50 provide extra protection.

Under the new rules, sunscreens can no longer be labeled as "waterproof" or "sweat-proof," since taking a dip or working up a sweat do make sunscreen less effective. Sunscreens now will be labeled as water- or sweat-resistant, with a time limit -- 40 or 80 minutes -- after which users should reapply sunscreen if they go for a swim or get sweaty.

Richard Bishop, emergency management specialist, Division of Strategic National Stockpile/CDC, presents information on RealOpt during a summit breakout session.

While Georgia Department of Public Health (DPH) emergency response planners had reason to be excited about last year's high Technical Assistance Review (TAR) score -- a 96 -- the most recent TAR was even better: 99.

While still awaiting some of the scores for the state's 18 health districts, leaders of the Strategic National Stockpile (SNS) program in Georgia are encouraged that successful collaborative efforts will continue to be reflected in the high marks received on these reviews.

"The state has done a wonderful job with providing guidance via the SNS summit presentations," said Dawona Hough, operations deputy director for DPH's Division of Health Protection. The annual summit was May 28-30 at Callaway Gardens in Pine Mountain.

"During the summit, the local public health districts and statewide planning partners attend developmental sessions addressing their previously identified needs," said Hough. "As a result, we have seen an increase in their TAR scores, as well as, collaboration with regional planning partners, which is in line with the 'whole of community' concept."

The focus of this year's meeting was "empowering communities through partnership, planning and preparation." Activities included panel discussions, breakout sessions and networking opportunities.

SNS Program Administrator Gladys Arome, Ph.D., said the intention is to continue fueling this positive trend.

"The state will continue to increase local planning partners' knowledge base via trainings and conferences, encourage innovative thinking that will result in statewide best practices and empower local partners to provide assistance and resources to their local communities."

While in some cases it may seem hard to improve a score that is at or near a perfect 100, state and local health districts will continue their focus on improvements while maintaining the efforts that are well recognized for their success.