Approximately one-third of boys and girls age 12 to 19 in the United States do not meet standards for physical fitness, according to a report in the October issue of Archives of Pediatrics & Adolescent Medicine, one of the JAMA/Archives journals.
The more physically fit a young person, the less likely he or she is to have high blood pressure, high cholesterol levels or a number of other risk factors for chronic diseases, according to background information in the article. 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. If so, it is likely that average physical fitness has also declined among youth in the same time period, since the last national survey.
Russell R. Pate, Ph.D., Arnold School of Public Health, University of South Carolina, Columbia, and colleagues assessed the physical fitness of 3,287 individuals age 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 home and then visited a mobile examination center, where they performed 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), the amount of oxygen consumed by the body during maximum exertion; the higher the VO2max, the better the individual's fitness level.
Estimated VO2max, and therefore physical fitness levels, were higher on average in males than in females and in youth of normal weight
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