Many children 'slower runners than their parents were' --- Many children cannot run as fast as their parents could when they were young, a study of global fitness says. -- Experts say the work - being presented at the American Heart Association's annual meeting - suggests children's fitness levels may be declining. -- To stay healthy, children and young people need to do at least an hour of physical activity - such as walking or cycling to school and running in the playground - every day. It can be done in small chunks rather than one session. -- More, Michelle Roberts - BBC