Millions of Adults, Teens Fail Fitness Test
Wednesday, December 21, 2005
A large proportion of Americans are out of shape, with teenagers in particular being surprisingly likely to be unfit, according to the first assessment of physical fitness nationwide.
Treadmill tests on a representative sample of more than 5,300 Americans ages 12 to 49 found that about one out of every five had poor cardiovascular fitness, including about one-third of teenagers and 14 percent of young adults. Based on the findings, an estimated 7.5 million adolescents and at least 8.5 million adults are out of condition, the researchers found.
The findings confirm for the first time what public health authorities had been fearing: that the increasing tendency to be sedentary may be taking a toll on Americans' fitness, putting them at risk for a host of health problems.
Although many previous studies have found that Americans have been getting less and less exercise in recent years and are becoming increasingly overweight, the new study marks the first time researchers have directly measured fitness nationwide.
"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 in the United States," said Mercedes R. Carnethon of Northwestern University, who led the study being published in today's issue of the Journal of the American Medical Association. "What we found is pretty worrisome."
Physical fitness is one of the best ways to protect health, with people who are not fit facing increased risk for virtually every major health problem, including heart disease, cancer, diabetes and Alzheimer's disease. The study indicates that a significant proportion of U.S. teenagers and young adults may be destined for heart disease and other ailments unless they start exercising more.
"Individuals with poor fitness are at markedly higher rate of dying," Carnethon said. "We should be very concerned about this."
In fact, the researchers found that the people in the study who scored lowest on the fitness test were likely to already have the major risk factors for the nation's No. 1 killer, heart disease: high blood pressure, high cholesterol, high blood sugar levels and being overweight.
"That was one of the most striking findings," Carnethon said. "We were surprised how many people already have significant risk factors."
Most concerning, she said, was that these risk factors were showing up among a significant proportion of teenagers who were out of shape.
"I'm surprised, in particular, about how high the numbers are among adolescents," Carnethon said. "This is setting the stage for major health problems later in life."
The findings are sobering, though not surprising, given societal trends that discourage exercise among children, such as the elimination of mandatory physical education classes in many schools and the increasing amount of time children spend watching television, playing video games and on the Internet, experts said.
"Kids are spending a lot more time in sedentary pursuits than they did a generation ago," said Stephen W. Farrell of the Cooper Institute, a Dallas research center that focuses on physical activity. "If you drive around your neighborhood nowadays you really don't see kids outside playing. It seems they only play sports if it's part of an organized league. Kids really just need to go out and play more."
Other researchers said they hope the findings might finally help reverse the trends of decreasing activity among teenagers and adults.
"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," said James O. Hill of the University of Colorado Health Sciences Center in Denver. "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."
For the study, Carnethon and her colleagues analyzed data collected by the National Health and Nutrition Examination Survey, an ongoing nationally representative survey conducted by the federal government to track important health trends. In 1999 through 2002, the survey for the first time directly measured physical fitness by subjecting the participants to eight-minute treadmill tests. By assessing how well their subjects' hearts and lungs responded to varying speeds and inclines on the treadmill, the researchers were able to determine their physical fitness.
Based on data collected from 3,110 adolescents ages 12 to 19, and 2,205 young adults ages 20 to 49, the researchers found that overall 19.2 percent fell into the low-fitness category, including 13.9 percent of adults and 33.6 percent of adolescents.
Adolescent boys and girls were about equally unfit, while adult females were significantly more unfit than adult males -- 16.2 percent compared with 11.8 percent, the researchers found. Blacks tended to be less fit than whites.
If anything, the study may have underestimated the level of unfitness among adults because those who had health problems were excluded from the testing, Carnethon said.
"I think we should be very worried," Carnethon said. "We have an obesity epidemic already. This is another explanation for that. And it doesn't seem as though the trends are changing for the better. We see decreasing levels of physical activity across all age groups."