Study: American teens are becoming more inactive

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BALTIMORE — The average American 19-year-old is as inactive and sedentary as the average American 60-year-old, according to a study released this month that was supported by the National Institute of Health.

The study, conducted by researchers from the Johns Hopkins Blomberg School of Public Health, also found that young women and girls were also less physically active than young men and boys.  However, after age 60, men became more sedentary than women.

The findings, which were published online June 1 in the journal, Preventive Medicine, come amid heightened concern that exercise deficits are contributing to the growing obesity epidemic, particularly among children and teens.

“Activity levels at the end of adolescence were alarmingly low, and by age 19, they were comparable to 60-year-olds,” said the study’s senior author, Vadim Zipunnikov, an assistant professor of biostatistics at John Hopkins.

Researchers surveyed more than 12,000 participants over three years. Study participants wore tracking devices that measured physical activity throughout the day, removing them only during bathing and at bedtime.

For all age groups, males generally had higher activity levels than females, particularly high-intensity activity, but after midlife, these levels dropped off sharply compared to females. Among adults 60 years and older, males were more sedentary and had lower light-intensity activity levels than females.

The study confirmed that recommended guidelines were not being met. For instance, the World Health Organization (WHO) recommends at least 60 minutes of moderate-to-vigorous physical activity a day for children ages five to 17 years. The study found that more than 25 percent of boys and 50 percent of girls ages six to 11 and more than 50 percent of male and 75 percent of female adolescents ages 12 to 19 had not met the WHO recommendation.

“The goal of campaigns aimed at increasing physical activity has focused on increasing higher-intensity exercise,” said Zipunnikov. “Our study suggests that these efforts should consider time of day and also focus on increasing lower-intensity physical activity and reducing inactivity.”