Regular physical activity helps teens avoid obesity
By Megan Rauscher
NEW YORK (Reuters Health) - Participating in physical activities in and out of school more than two times a week protects adolescents from becoming overweight young adults, according to new research.
"The message for policy makers is that the failure to offer physical education is 'penny wise and pound foolish,"' study investigator Dr. Robert Wm. Blum from Johns Hopkins University, Baltimore, told Reuters Health.
"For parents, the evidence is compelling that placing an emphasis on high-energy recreational activity such as biking and roller-blading will benefit their children and are activities that they can do together as a family," he added.
The study, published in the Archives of Pediatrics and Adolescent Medicine, involved 3,345 adolescents who reported their school-based and extracurricular physical activities in 1996 when they were in the 8th through 12th grades. Body weight was assessed at this time and again 5 years later.
During the 5-year period, the number of adolescents who were overweight - defined as having a body mass index (BMI) of 25 or greater -- nearly doubled from about 28 percent to 51 percent, the investigators report. BMI is the ratio between height and weight, which is commonly used to assess an individual's weight.
"Of 941 overweight adolescents, only 103 (11 percent) transitioned to normal weight as young adults," the researchers report. Of the 2,404 normal-weight adolescents, 855 (roughly 36 percent) became overweight young adults.
For the entire study population, the likelihood of being an overweight adult was reduced 48 percent by participating extracurricular "wheel-related" activities, such as roller-blading, skateboarding, or bicycling more than 4 times per week and 20 percent by participating in school-based sports activities, such as baseball, softball, basketball, soccer, swimming or football 3 to 4 times per week.
Moreover, for every weekday an adolescent participated in physical education classes, the odds of becoming an overweight adult decreased by 5 percent. Participating in physical education classes everyday decreased the odds of becoming an overweight adult by 28 percent.
"With obesity at epidemic proportions, an intervention which appears to hold as much promise as daily physical education does in maintaining normal weight into adulthood should be given highest priority," Blum said.
The apparent protective effect of physical activity against becoming overweight was more marked in adolescents who started out at a normal weight, suggesting that physical activity may be a more effective strategy for maintaining normal weight than for losing excess body weight, the researchers point out.
The study results also highlight the importance of preventing a child from becoming overweight in the first place, they add.
SOURCE: Archives of Pediatrics and Adolescent Medicine, January 2008.