Two-Thirds of U.S. Youth Check Out as Physically Fit

COLUMBIA, S.C., Oct. 3 -- Approximately a third of U.S. boys and girls, ages 12 to 19, failed to meet cardiovascular fitness standards, with overweight and sedentary lifestyles taking much of the blame, according to a national survey.

Boys were more fit than girls, while older boys had higher fitness scores than younger boys, reported Russell Pate, Ph.D., of the University of South Carolina, and colleagues, in the October issue of the Archives of Pediatrics & Adolescent Medicine.

Among girls, the reverse was true with younger girls having higher scores than older girls. Race and ethnicity were not factors.

The study included a sample of 4,732 young people from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2002. Complete data were available for 3,287 of the participants, a demographically comparable sample, the researchers said. Fitness as measured by maximal oxygen uptake (VO_2max) was determined by a submaximal treadmill exercise test.

Normal weight was defined as less than the 85^th percentile of BMI for age. At-risk-for-overweight was above the 85^th percentile but less than the 95^th percentile. Overweight was at or higher than the 95^th percentile.

Estimated VO_2max was higher in boys (mean SE, 46.4 0.4) than in girls (38.70.3), but did not differ across race and ethnicity groups. Mean VO_2max, was approximately 17% lower among girls than boys in the overall sample, the researchers reported.

Generally, among males, older participants, ages 18 to 19, were more likely to meet standards for VO_2max than those ages 12 to 13 (71.7% vs 55.3%). Among girls, the opposite was true. Of the younger participants, 64.1% met the standards compared with 62.3% of the older girls.

For both boys and girls, those in the normal weight group had significantly higher estimated fitness levels than those in the at-risk-for-overweight and overweight groups. Physical activity promoted physical fitness, whereas a sedentary lifestyle was linked to diminished physical fitness.

For example, boys who commuted through walking or biking, participated in vigorous physical activity, or did strengthening exercises during the previous 30 days were more fit than those who did not report these activities (VO_2max 49.2 vs 41.9 P

Accordingly, they said, several expert panels have recommended that physicians counsel pediatric and adolescent patients about the importance of meeting current physical activity guidelines.