Children who spent a lot of time in daylight were calmer


Kindergarten children were equipped with bracelets that measure light exposure. A study found a link between lots of daylight and low hyperactivity in the children.

Anne Lise Stranden

Wednesday 21. april 2021

Children who spent a lot of time outdoors during the day displayed fewer symptoms of hyperactivity.

A new study of kindergarten children show this to be a strong link.

“The difference between the brightness of indoor and outdoor light is considerable,” says Vidar Sandsaunet Ulset, who is a psychologist and postdoctoral fellow at Promenta Research Centre at the University of Oslo. He is one of the researchers behind the study.

The study is a small part of a larger research study of 2000 children.

Previously, researchers have found a connection between the amount of time that children in kindergarten spend outdoors and higher levels of concentration and less hyperactivity in school.


Huge difference between indoor and outdoor light intensity

Ulset says it’s conceivable that our body is adapted to outdoor lighting.

“I think there’s a mismatch between the environment we’re created to be in and the environment we mostly spend time in,” Ulset says. He points out that people have been indoors during the day for only a small fragment of human history.

“There’s a huge difference between indoor and outdoor light intensity,” he says.

Outdoors on a sunny day, the illuminance can be 100 000 lux, whereas the light in the living room might be only 500 lux, according to Ulset.

“We don’t usually notice the difference, because our eyes adapt to new light levels quickly,” Ulset says.

More recent research now indicates that it may be wise for kindergarten children to spend a lot of time outside, he says.

Light might act like ADHD medication

Ulset is now wondering if outdoor daylight affects the brain somewhat in the same way as ADHD medication does.

“Several studies on both adults and children show that light triggers hormones in the brain that improve attention,” he says.

Studies show that light can trigger norepinephrine which, like medications prescribed for ADHD, can improve attention and concentration.

Ulset says he is eager to do more research on the topic of outdoor time and hyperactivity in children.


V. Ulset et al: Environmental Light Exposure, Rest-Activity Rhythms, and Symptoms of Inattention and Hyperactivity: An Observational Study of Australian Preschoolers. SummaryJournal of Environmental Psychology, 21 February 2021.

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