"Improving physical activity, reducing sedentary time and ensuring quality sleep in young children will improve their physical, mental health and wellbeing", Dr Fiona Bull, program manager for surveillance and population-based prevention of noncommunicable diseases, at the WHO says, "and help prevent childhood obesity and associated diseases later in life".
3- to 4-year-olds shouldn't go over one hour of screen time.
"Sedentary behaviors, whether riding motorized transport rather than walking or cycling, sitting at a desk in school, watching TV or playing inactive screen-based games are increasingly prevalent and associated with poor health outcomes", the WHO said.
The institution also recommended that children between two and four years of age should not experience sedentary screen time for more than one hour per day.
World Health Organization recommends that infants should be physically active several times a day, particularly through floor-based play.
The WHO said under-fives should be physically active and getting plenty of sleep, under-fives would establish healthy habits through adolescence and into adulthood.
Despite acknowledging that its "strong recommendations" were based on "very low quality evidence", the United Nations health agency said its advice could apply to all young children, regardless of gender, cultural background or socio-economic status. More is better. These children should not be restrained for more than one hour at a time or sit for extended periods.
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 a day, the agency said.
Instead, "when sedentary, engaging in reading and storytelling with a caregiver is encouraged", the organisation said of young children. Is WHO's recommendation sensible or unrealistic?
Early childhood is a period of rapid physical and cognitive development during which habits are formed and family lifestyle routines are adaptable, said the World Health Organization guidelines, drawn from evidence in hundreds of studies, many from Australia, Canada, South Africa and the United States.
Children between one and four should spend at least three hours in a variety of physical activities spread across the day, with no more than an hour of screen time.
WHO's screen time advice "overly focuses on quantity of screen time and fails to consider the content and context of use", said Andrew Przybylski, director of research at the Oxford Internet Institute at the University of Oxford.
"None would contest the fact that increasing physical activity, sleep, and health are important goals and it is possible that screens impact young people in a wide range of ways but we won't know that until good scientific studies are done".
Some groups said WHO's screen time guidelines failed to consider the potential benefits of digital media. Screen time is not recommended.