Teenagers who are physically inactive and lead sedentary lifestyles do not experience the benefits of physical activity, which have been noted in the previous tab (see 'Benefits of Physical Activity in Teenagers').
Lack of physical activity can impair the healthy growth and development of teenagers and negatively impact on their health and fitness.
Physical inactivity in adolescence can also cause numerous and long-term negative consequences by placing teenagers at risk of poor physical, social, intellectual, emotional and mental health outcomes in adulthood.
Physical inactivity and sedentary lifestyles have been identified as a health epidemic in developed countries where it has become a major public health concern, causing significant morbidity and mortality in adulthood and reducing life expectancy.
Research indicates poor health outcomes commence in adolescence and coincide with the changes that occur in teenage physical activity behaviours.
As sedentary and physically inactive teenagers move into adulthood, they may place themselves at risk of developing cardiovascular disease (high blood pressure, high cholesterol, coronary heart disease), bowel and breast cancers, stroke, arthritis, type-2 diabetes and osteoporosis. They also place themselves at risk of becoming overweight, changing their body's fat to muscle composition and developing obesity. This has other implications such as reduced fertility.
Physical activity causes the release of endorphins ('happy hormones') which can improve mood; inactivity is associated with increased feelings of stress, anxiety and depression.
Taken together, these health disorders are chronic and cause a reduction in quality of life and are associated with significant public health costs.