One-Third of U.S. Teens Have Low Fitness Levels, Study Finds

More than one-third of U.S. teenagers and about 14% of young adults have low levels of cardiovascular fitness, according to the first nationwide study of physical fitness, the Washington Post reports. For the study, which appeared on Wednesday in the Journal of the American Medical Association, researchers from Northwestern University analyzed data collected by the National Health Nutrition Examination Survey, which measured the physical fitness of participants through eight-minute treadmill tests. The tests assessed heart and lung response to different speeds and inclines.

The survey collected data for 3,110 children ages 12 to 19 and 2,205 adults ages 20 to 49 between 1999 and 2002. Overall, 19.2% of participants -- 33.6% of teens and 13.9% of young adults -- had low fitness levels, the study finds. Based on the results of the study, researchers estimated that about 7.5 million U.S. teens and 8.5 million young adults are unfit. According to the study, participants with low fitness levels were likely to have major risk factors for heart disease, such as high blood pressure, high cholesterol and high blood sugar levels. The study finds that an equal percentage of teen boys and girls had low fitness levels; about 16.2% of young adult women had low fitness levels, compared with about 11.8% of young adult men, according to the study. The study also finds:

• Black participants on average had lower fitness levels than white participants (Stein, Washington Post, 12/21);
  
  
• Black teen girls and Mexican-American teen boys were the most likely groups to have low fitness levels (Szabo, USA Today, 12/21);
  
  
• Participants who had low fitness levels were two to four times more likely to be overweight or obese than those with moderate or high fitness levels;
  
  
• About 4% of teen girls and 2% of teen boys had high blood pressure;
  
  
• About 7% of teen boys and 2% of teen girls had metabolic syndrome;
  
  
• Average cholesterol levels among teens who had low fitness levels were about 10 points higher than those among teens who had high fitness levels (Tanner, AP/Boston Globe, 12/21).

According to Mercedes Carnethon, lead author of the study, the study might have overestimated the fitness level of young adults because those with health problems were excluded from the study. She said, "This is something that we thought was happening, and that we have been concerned about. But no one had ever documented before how poor fitness actually is across the population." Carnethon added, "Individuals with poor fitness are at a markedly higher rate of dying. We should be very concerned about this."

James Hill, director of the Center for Human Nutrition at the University of Colorado Health Sciences Center, said, "This really points out that the low level of physical activity in our population is leading to a lot of kids and adults having low fitness levels, and those low fitness levels are related to a lot of bad outcomes," adding, "We haven't been able to communicate to the public what a crisis this is. It's scary. Maybe this will be a wake-up call."

Stephen Farrell of the Cooper Institute, said, "Kids are spending a lot more time in sedentary pursuits than they did a generation ago. If you drive around your neighborhood nowadays you really don't see kids outside playing." He added, "It seems they only play sports if it's part of an organized league. Kids really just need to go out and play more" (Washington Post, 12/21). An abstract of the study is available online.