A study conducted by researchers from the Johns Hopkins School of Public Health sounds the alarm about the lack of physical activity among children and teens, and its contribution to the growing obesity epidemic among those age groups.

“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, assistant professor in the Bloomberg School’s Department of Biostatistics, in a media release from Johns Hopkins University Bloomberg School of Public Health.

“For school-age children, the primary window for activity was the afternoon between two and six PM. So the big question is how do we modify daily schedules, in schools for example, to be more conducive to increasing physical activity?”

The study was published recently in the journal Preventive Medicine.

The researchers examined the data obtained from the 12,529 participants in the National Health and Nutrition Examination Survey, which measured how much time they were sedentary or engaged in light or moderate-to-vigorous physical activity. Time periods studied were the 2003-2004 and 2005-2006 survey cycles.

The researchers broke down findings into five age groups: children (ages six to 11); adolescents (ages 12 to 19); young adults (ages 20 to 29); adults at midlife (ages 31 to 59); and older adults (age 60 through age 84). Forty-nine percent were male, the rest female.

Activity among 20-somethings, the only age group that saw an increase in activity levels, was spread out throughout the day, with an increase in physical activity in the early morning, compared to younger adolescents. The increase may be related to starting full-time work and other life transitions.

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% of boys and 50% of girls ages six to 11, and more than 50% of male and 75% of female adolescents ages 12 to 19, had not met the WHO recommendation, the release explains.

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

[Source(s): Johns Hopkins University Bloomberg School of Public Health, Science Daily]