Principal investigator Matthew Kwan, a postdoctoral fellow of the Michael G. DeGroote School of Medicine at McMaster University in Hamilton, Ontario, found a 24 percent decrease in physical activity during the 12 years from adolescence to early adulthood. The steepest declines were among young men entering university or college.
Using data from Statistics Canada's National Population Health Survey, the researchers tracked 683 Canadian adolescents ages 12-15, who were interviewed twice a year until they were ages 24-27.
"This is a critical period, as the changes in physical activity during the transition from late adolescence to early adulthood represents the most dramatic declines in physical activity across a person's life," Kwan said in a statement. "In particular, the transition into post-secondary is a one-time period when individuals become much less active."
The study, published in the American Journal of Preventive Medicine, found the rate of decline in physical activity was greater for men than for women, who showed only a modest 1.7 per cent decrease in their overall activity levels. However, the women had been less active in high school.
"It may be that girls experience the greatest declines in physical activity earlier in their adolescence," Kwan said.