“Between the 1950s and the 1980s, regular surveys of youth physical fitness were conducted in the United States. An increasing proportion of children have become obese since the 1980s, which may be explained by a decrease in physical activity,” Pate said. “If so, it is likely that average physical fitness also has declined among youth in the same time period, since the last national survey.”

Pate and colleagues from the Centers for Disease Control and Prevention and The Cooper Institute assessed the physical fitness of 3,287 youth ages 12 to 19 who participated in the government-conducted National Health and Nutrition Examination Survey between 1999 and 2002. The participants were interviewed in their homes and then visited a mobile examination center, where they had a treadmill exercise test consisting of a two-minute warm-up, two three-minute periods of exercise and a two-minute cool-down.

During the test, researchers measured blood pressure, heart rate and rate of perceived exertion, determined by asking participants to rate how hard they feel their bodies are working. Heart rate readings during the three-minute periods of exercise were used to estimate maximal oxygen uptake (VO2max), which is the amount of oxygen consumed by the body during maximum exertion: Higher uptake levels mean an individual is more fit.

Estimated VO2max, and therefore physical fitness levels, were higher on average in males than in females and in youth of normal weight than those who were overweight. However, there were no differences across racial or ethnic groups.

Older males were more physically fit than younger males, while the opposite was true for females. Participants who reported more sedentary behavior, such as watching television or playing video games, and those who spent less time being physically active were more likely not to be physically fit.

“This represents a significant public health problem because low physical fitness during adolescence tends to track into adulthood, and adults who are less physically active are at a substantially increased risk for chronic disease morbidity (illness) and mortality (death),” the authors wrote in the study.

Because active youth tend to be more physically fit, experts recommend that physicians counsel children and parents about guidelines for physical activity, said Pate, who was the author of a recent report by the American Heart Association that called on schools to offer more physical education programs.

“This study is another indicator of the importance of physical activity in the lives of young people,” Pate said. “Clearly, we must do more as a nation to support fitness among all youth.”

Oct. 2006, The Archives of Pediatric and Adolescent Medicine

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FACT:
Despite knowledge of the benefits of fish oil, family physicians infrequently recommend fish oils for their CVD patients. Since consumption of fish oil has been shown to reduce mortality in patients with cardiovascular disease (CVD), this study by US researchers aimed to determine the frequency and associations of dietary fish prescribing by family physicians via a survey to Washington State family physicians. They found that nearly all agreed that nutrition is important in CVD prevention (99%) and felt that they have an essential role in giving dietary advice (92%). The majority (57%) knew of fish oil’s effectiveness in secondary prevention of CVD. However, only 17% of respondents were identified as high fish prescribers. Knowledge of fish oil’s benefit in sudden death reduction was associated with higher fish prescribers in the analysis. The researchers concluded: “Despite knowledge of fish oil’s benefit and favorable attitudes toward nutritional therapy, family physicians infrequently recommend fish oils for their CVD patients. Strategies improving awareness of fish oil’s effects on sudden death and reducing time barriers associated with dietary counseling should be explored further to increase recommendation of this important advice.” The Journal of the American Board of Family Medicine 19:459-467 September-October 2006.