Teens Should Exercise!

Exercise may help teens counteract genetic propensity for obesity.
The Los Angeles Times (4/5, Stein) "Booster Shots" blog reported, "Genetics may be one factor that causes obesity, but according to a new study " in the Archives of Pediatrics & Adolescent Medicine, "those genes might not hold sway over an adolescent's weight -- if that teen exercises."
Before reaching that conclusion, researchers in Sweden "collected data on 752 teens who took part in the Healthy Lifestyles in Europe by Nutrition in Adolescence Cross-Sectional Study, which was conducted in 10 European countries between October 2006 and December 2007," HealthDay (4/5, Reinberg) reported. "Among these teens, 37 percent did not have FTO mutations, 47 percent had one copy, and 16 percent had two copies." Indeed, "copies of the mutation were linked with higher body mass index," and "a higher percentage of body fat and a larger waist."
But, "an hour a day of moderate to vigorous exercise can overcome the effect of" rs9939609, the "so-called A allele of the fat mass- and obesity-associated gene, or FTO," MedPage Today (4/5, Smith) reported.
Notably, "the research supports US guidelines that tell children and teenagers to get an hour or more of physical activity daily, most of it aerobic activity such as running, jumping rope, swimming, dancing and bicycling," the AP (4/6, Johnson) reports.
Maternal exercise during pregnancy may lower baby's birth weight. The Los Angeles Times (4/5, Roan) "Booster Shots" blog reported that, according to a study published online March 24 in the Journal of Clinical Endocrinology & Metabolism, "exercise during pregnancy may help babies start life at a healthy weight." After comparing "84 first-time mothers who either exercised during pregnancy or were sedentary," researchers found that the mothers who exercised delivered "babies that were, on average, three to five ounces lighter than the babies of the non-exercisers."
"The babies born to the exercisers had a lower body weight and a lower...BMI," WebMD (4/5, Doheny) reported. Notably, "there were no differences in the length of the babies, on average, between exercisers and non-exercisers." Neither pregnancy duration nor maternal weight was affected.
HealthDay (4/5, Preidt) reported that "study co-author Dr. Paul Hofman, of the University of Auckland in New Zealand, said in an Endocrine Society news release" that, "given that large birth size is associated with an increased risk of obesity, a modest reduction in birth weight may have long-term health benefits for offspring by lowering this risk in later life.'