The British government says children under five _ including those who can't walk yet _ should exercise every day.
The new guidelines were issued Monday, partly to fight the obesity epidemic.
In them, the department of health says children under five who can walk should be physically active for at least three hours a day. Officials say parents should reduce the amount of time kids spend being sedentary, like watching television or strapped in a stroller.
For babies who can't walk yet, the government says physical activity should be encouraged from birth, including infants playing on their stomach and swimming sessions with their parents.
Officials hope encouraging young children to exercise will prevent them from becoming obese adults later, which could put them at risk of heart disease, diabetes and cancer.