A link between mental strain and studying in adolescents has been identified

According to a study, prolonged sitting associated with doing homework and other active pursuits showed a stronger correlation with teenagers' mental state than passive activities such as watching television. However, this does not mean that studying causes more stress than using a phone or directly leads to mental health issues.

Scientists studied data from thousands of teenagers

Researchers from Beijing Normal University analyzed data from 8,753 adolescents as part of the United Kingdom Millennium Cohort Study. The results of the study were published on October 15, 2026, in the scientific journal Scientific Reports.

Scientists examined the participants' physical activity and sedentary time at the age of 14. Three years later, when they reached 17, the level of mental strain was assessed.

Researchers developed an index called PASTBI to calculate the ratio of physical activity to sedentary time. Through this, they checked how physical activity relates to mental health and whether the results vary depending on body weight.

There is a difference between doing homework and watching TV

According to the analysis, sedentary time associated with active mental pursuits, such as doing homework, showed a stronger correlation with mental strain than passive activities like watching television.

In the authors' calculations, the difference between these two correlation indicators was nearly 11-fold. However, this figure does not mean that studying increases stress by 11 times. It represents the mutual ratio of statistical correlation indicators.

The study also does not prove that studying itself is harmful. Factors such as exams, the pursuit of high grades, parental expectations, and a lack of sufficient time to relax can affect adolescents' mental state. However, this study did not examine each of these individually.

The impact of physical activity is also not uniform

In the study, an inverse correlation was observed between physical activity and mental strain among adolescents with normal weight. That is, it was found that those with higher levels of physical activity tended to have lower indicators of mental strain.

Among adolescents with overweight or obesity, this correlation did not manifest in a simple linear form. Further analyses showed that physical activity might have a more complex relationship with mental health. However, this result is based on preliminary analyses and should be interpreted with caution.

The study authors emphasize that improving the ratio of physical activity to sedentary time may help support mental health. However, additional research is needed to accurately assess its impact.

Overall, the results indicate that adolescents' mental health cannot be explained solely by screen time. Physical activity, daily routines, and time allocated for rest can also play an important role.