Physical activity, screen time and eating habits are linked to brain health in young people

Few adolescents achieve the recommendations for physical activity, healthy eating habits and screen time. At the same time, young people's mental health is deteriorating. Researchers at GIH have investigated these lifestyle habits and the link to mental health and cognitive abilities in a study of schoolchildren.

"We saw that the general state of knowledge about the link between physical activity and brain health was not sufficient to be able to give advice to schools and individuals about how much you need to move for the brain to feel good. With more detailed knowledge, we can design interventions in schools for young people to have better brain health," says Örjan Ekblom, professor at GIH and principal investigator of the study.

In 2019, a cross-sectional study was conducted among 1,139 students in grade 7. They wore a motion tracker on their hip for seven days to measure physical activity and sedentary behaviour at a detailed level. The pupils were also asked to fill out questionnaires about lifestyle and health, keep a food diary for three days and perform various tests, such as a memory test as a measure of cognition.

Few achieve the recommendations

The study found that only one-third reached the recommendations of at least 60 minutes of daily physical activity at moderate to high intensity. They spent an average of three-quarters of the day sedentary, which equates to about 10 hours per day. The researchers also saw that more physical activity and less sedentary behaviour were linked to less anxiety and higher quality of life in the adolescents in the study.

"However, since it's a cross-sectional study, we can't say what is cause and effect," explains Örjan Ekblom and continues:
"Our results provide a snapshot of potential associations that may indicate how physical activity and other lifestyle habits are linked to brain health.

The results showed clear differences between boys and girls. Boys generally move more and experience better general and mental health and less stress than girls, but have more difficulty concentrating. The boys also had less screen time, at least on weekends.

Better quality of life with less screen time and a varied diet

Screen use among Swedish schoolchildren is increasing. GIH's study showed that almost half of the adolescents spend more than five hours a day in front of a screen on weekends, and a fifth on weekdays.

"There is a risk when you have high screen time that you do not have time for other activities, which we clearly saw in our study," says Björg Helgadottir, one of the researchers behind the study.
"Those who had a high level of screen time had less physical activity both on weekdays and weekends. More screen time was also linked to poorer sleep, more anxiety and lower quality of life.

When the researchers looked at the adolescents' eating habits, there was generally too little variation and too little nutrition, and very few achieved the recommendations of 500 grams of fruit and vegetables a day. An interesting result was that a more varied diet and a lot of fruit and vegetables were found to be linked to a higher quality of life in the adolescents.

Popular science reports and films

The cross-sectional study is part of a larger research project that ran from 2017 to 2023. The results are summarised in a series of short popular science reports and films that will be available from spring 2024.

The project is part of the E-PABS Research Center for Physical Activity, Brain Health and Sustainability and has been carried out with the support of the Knowledge Foundation and in collaboration with Skandia, Generation Pep, COOP, the Consumer Association in Stockholm, IKEA and Skanska.

Read more about the study Brain health in school – Physical activity for healthy brain functions among schoolchildren