GENEVA • Children aged two to four should not be allowed more than one hour of "sedentary screen time" per day, the World Health Organisation (WHO) said yesterday.
Infants less than one year old should not be exposed to electronic screens at all, it added.
The United Nations agency, issuing its first such guidelines, said under-fives should also be physically active and get adequate sleep to help develop good lifelong habits and prevent obesity and other diseases in later life.
Sedentary screen time would include watching television or videos and playing computer games.
"Healthy physical activity, sedentary behaviour and sleep habits are established early in life, providing an opportunity to shape habits through childhood, adolescence and into adulthood," said WHO in the guidelines to member states.
For infants under one, WHO recommends at least 30 minutes of physical activity a day, including prone position - or tummy time - for those not yet mobile, it said.
Babies under one should also not be restrained in a pram, highchair or strapped to someone's back for more than an hour at a time, and should sleep between 12 and 17 hours per day, it said.
For infants between one and two years old, WHO recommends two hours of physical activity per day, with no more than an hour of "sedentary screen time", and at least 11 hours of sleep.
And for children aged three to four, two hours of daily physical activity should include at least an hour of "moderate to vigorous" movement, while screen time should be kept under an hour.
Being inactive is a "leading risk factor" for mortality and fuels the global rise in obesity, WHO noted.
In a report two years ago, WHO said the number of obese children and adolescents worldwide had jumped tenfold to 120 million in the past 40 years, and that the rise was accelerating in low-and middle-income countries, especially in Asia.
Early childhood is a period of rapid physical and cognitive development during which habits are formed and family lifestyle routines are adaptable, it said in the guidelines, drawn from evidence in hundreds of studies, many from Australia, Canada, South Africa and the United States.
Several experts noted, however, that WHO's broad recommendations were based on thin evidence.
Professor Andrew Przybylski, director of research at the Oxford Internet Institute at Oxford University, agreed that while restricting screen time among young children appeared to "make sense... in many ways the conclusions drawn about screens are out of step with scientific evidence of harm".
"Not all screen time is created equal," he added, urging WHO to call for "higher quality studies" to more broadly assess the various types of screen-based activities available to children and their impact.
REUTERS, AGENCE FRANCE-PRESSE