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A significant majority of teenagers don’t get the recommended 60 minutes of exercise per day, a new study has found.
Looks like teenagers being lazy is more than just a stereotype.

A new study conducted by researchers from the Johns Hopkins Bloomberg School of Public Health in Baltimore looked at more than 12,500 people's exercise habits by having them wear fitness trackers for a week. When they separated that data by age, they found something alarming about teenagers.

"Activity levels at the end of adolescence were alarmingly low, and by age 19, they were comparable to 60-year-olds," says the study's senior author, Vadim Zipunnikov.

Children between ages 5 and 17 are supposed to get 60 minutes of moderate-to-vigorous exercise in a day, according to the World Health Organization guidelines. People 18 and older should get 150 minutes of exercise per week - about 20 minutes per day.

More than 25 percent of boys and 50 percent of girls between ages 6 and 11 did not meet those guidelines, and 50 percent of boys and 75 percent of girls between ages 12 and 19 did not meet the threshold.

"For school-age children, the primary window for activity was the afternoon between 2 p.m. and 6 p.m.," Zipunnikov said. "So, the big question is, how do we modify daily schedules, in schools, for example, to be more conducive to increasing physical activity?"

Meanwhile, a study in 2008 found 20 percent of schools had reduced recess time between 2001 and 2007. Common Core standards seem to have inspired more cuts in recess since then, despite numerous studies that show recess is beneficial to both children's physical and mental health.

But teens aren't the only ones spending too much time on the couch. Activity tends to increase from the teenage low as adults are in their 20s, but then activity levels steadily drop off at every other age level, according to the study.

Men tended to be more active than women in early and mid-life, but then experienced a sharp drop off, with women tending to be more active than men over age 60.

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