What if the sedentary lifestyle of adolescents took root… in early childhood? While nearly 80% of young people around the world do not move enough according to the World Health Organization, a study conducted by the University of Montreal sheds new light. By following nearly 1,700 children for more than ten years, researchers demonstrate that the behaviors adopted from the age of 2 and a half directly influence the level of physical activity at 12 years old.
Three key habits that change everything
The results are clear: three early behaviors play a determining role. Active play with parents, limited screen time and adequate sleep are the pillars of a long-term active lifestyle.
Each good habit adopted at 2 and a half years old translates into approximately five additional minutes of outdoor play per day at the age of 12. A cumulative effect which may seem modest, but which becomes significant over a decade.
However, less than one child in ten naturally respects these three recommendations from an early age. A figure that worries researchers, especially since these habits act independently of family context, income or even the child’s temperament.
Lasting effects, even ten years later
What sets this study apart is its scientific robustness. Based on a representative cohort and rigorous longitudinal monitoring, it shows that motor habits are not simple passing preferences.
On the contrary, they are deeply anchored in children’s daily lives. Those who play regularly with their parents or spend less than an hour a day in front of a screen at 2.5 years old are significantly more active in adolescence.
According to researchers, the most determining factor remains active time shared with parents. This moment creates a positive association between movement, pleasure and social interaction — a powerful lever for establishing sustainable behaviors.
Girls, particularly exposed to a sedentary lifestyle
The study also highlights a concerning gender disparity. At 12 years old, only 14.9% of girls are considered active, compared to 24.5% of boys.
For girls, good habits started in early childhood play an even more protective role. Active play and limiting screen time act as a shield against the “sedentary slide” observed during adolescence.
These results underline the importance of intervening very early, particularly with families, to encourage an active lifestyle from the earliest years.
A clear message for parents and public policies
The main lesson of this research is clear: family habits lastingly shape children’s health. Encouraging movement, limiting screen time and ensuring good sleep are not simple recommendations — they are long-term investments.
Researchers are therefore calling for better dissemination of WHO recommendations for children under five: at least 180 minutes of physical activity per day, a maximum of one hour of screen time and between 11 and 14 hours of sleep.
In other words, to fight against a sedentary lifestyle in adolescents, everything starts well before… sometimes from the first steps.