Physical activity and health in adolescence.

Adolescence represents a critical period of development during which personal lifestyle choices and behaviour patterns establish, including the choice to be physically active. Physical inactivity, sedentary behaviour and low cardiorespiratory fitness are strong risk factors for the development of chronic diseases with resulting morbidity and mortality, as well as economic burden to wider society from health and social care provision, and reduced occupational productivity. Worrying trends in adverse physical activity behaviours necessitate urgent and concerted action. Healthcare professionals caring for adolescents and young adults are ideally placed and suited to deliver powerful messages promoting physical activity and behaviour change. Every encounter represents an opportunity to ask about physical activity, provide advice, or signpost to appropriate pathways or opportunities. Key initial targets include getting everyone to reduce their sedentary behaviour and be more active, with even a little being more beneficial than none at all.