CHILDREN AGED TO three who spend more than three hours a day viewing screens such as tablets and televisions are less physically active when they are five and a half years old, compared to children who use screens for an hour or less each day, a study has found.

World Health Organization (WHO) guidelines state that limiting screen time to one hour per day or less among children aged two to five years may promote healthier behaviour in later life, and new research would appear to back this up.

The study, involving more than 500 children in Singapore, is one of the first of its kind to focus on children of this age, rather than older children and adolescents.

Parents were asked to track how much ‘screen time’ their children had every day such as watching TV or using a computer, mobile phone or tablet.

These screen habits were recorded when the children were aged two and again at age three. An average of the two recordings were used in the analysis.

At age five, the children wore an activity tracker continuously for seven days to monitor their sleep, sedentary behaviour, light physical activity, and moderate-to-vigorous physical activity.

Children in the study spent an average of 2.5 hours a day watching screens at age two to three. Television was the most commonly used device and was associated with the longest viewing time. Only a small proportion of children in the study met WHO recommendations of one hour per day or less.

The findings of the study, which is published in The Lancet Child and Adolescent Health journal, found that children who had used screens for three or more hours a day at age two to three spent an average of 40 minutes more time sitting down each day at age five than did those who had used screens for less than an hour a day at the same ages.

Doesn’t appear to affect sleep

Such higher screen use in infancy was associated with around 30 minutes less light physical activity each day, and around 10 minutes less moderate to vigorous activity each day, the study found. 

Similar effects were observed regardless of the type of screen children used. Higher screen time in early childhood did not appear to affect sleeping habits at age five, however. 

Screen viewing is increasingly prevalent but excessive screen time in childhood has been linked to a range of health problems, including “increased obesity risk, reduced motor and cognitive development, and worse psychosocial health”, the report notes.

The authors of the new study have noted some limitations to the research, including that parents may be biased in their reporting of their child’s screen use, and that the study did not control for other health behaviours such as diet, sleep, physical activity, or environmental factors such as time in childcare because there was limited information about these available.

However, the authors added that the findings were still similar when they conducted an additional analysis to see how much of an impact health behaviours had.

Bozhi Chen, of the National University of Singapore, said the analysis carried out by her and her colleagues “addresses an important research gap and strengthens existing evidence linking screen viewing time with later child health”.

“Our findings support public health efforts to reduce screen viewing time in young children and suggest further research into the long-term effects of screen viewing on movement behaviours is needed.”

The report itself states: “In this rapidly evolving digital age, children’s screen use is a key concern for parents and medical bodies. Guidelines to limit screen time have been released by many governments and WHO, however, screens offer digital and social connectedness and educational opportunities.

“Future research is needed to assess the influence of media content, to determine optimum durations of screen time in the context of 24-hour time use.”