(HealthDay)—More and more U.S. teens now fall short when it comes to cardiorespiratory fitness, a new government report shows.
Using a specific measure, the researchers found that only about half of boys and one-third of girls between the ages of 12 and 15 had adequate levels of cardiorespiratory fitness. The overall percentage of fit teens went from 52.4 percent in 1999 to 42.2 percent in 2012, according to the U.S. National Center for Health Statistics, part of the U.S. Centers for Disease Control and Prevention.
Cardiorespiratory fitness involves the ability of the circulatory and respiratory systems to support continuous physical activity. It's measured by maximal oxygen uptake, also known as VO2max. This is the greatest capacity of the body to use oxygen during exercise.
Regardless of their age, boys had better cardiorespiratory fitness than girls, according to data gleaned from national surveys. Although levels of cardiorespiratory fitness among teens did not vary by race or income, the survey data revealed this measure of fitness did decline as weight increased.
A smaller percentage of overweight and obese young people had adequate levels of cardiorespiratory fitness than teens who maintained a normal weight. This is particularly significant, given that about one in five U.S. teens between the ages of 12 and 19 is obese.
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The U.S. Centers For Disease Control and Prevention provides more information on teen health and physical activity.