Regular and goal-appropriate exercise is critical to improving and maintaining both health and performance. However the frequency, intensity, duration, and type of activities needed to optimise health or achieve successful sports performance will differ considerably depending upon an individual’s goals and capabilities. Although sport is one of many forms of exercise that can be counted toward daily physical activity, participation in sport is not necessary to meet current physical activity recommendations. The current consensus is that the minimum amount of physical activity needed to improve and maintain good health is 30 minutes each day of moderate-intensity activity at least five days per week. The evidence supporting this consensus is based on predominantly observational evidence that performing regular aerobic- (endurance) type physical activity is associated with reduced morbidity and premature mortality from CVD, CHD, stroke, and colorectal cancer. The exact dose needed to improve health and the slope of the dose-response gradient between physical activity and mortality for various diseases are not known, and one major limitation of the existing evidence is the lack of objective measurement of physical activity. Limited evidence indicates that a much higher dose of activity (45 to 90 minutes each day at least five days per week) may be needed to prevent overweight and obesity and to avoid weight regain in previously overweight and obese individuals. The role of resistance training and heavy domestic work in reducing morbidity and premature mortality for various diseases is unclear. As most adults do not meet current recommendations there is a critical need for innovative approaches to increase physical activity across large-scale populations.