["Unfair" effect of physical activity. Physically inactive individuals must exercise for a longer period to achieve the preventive targets].

: The capacity to turnover energy during exercise is regulated by the maximal aerobic capacity. Advices regarding physical activity must therefore be modified and individualised based on the maximal aerobic capacity of the patient. Initially, physical training of patients with low capacity to turn over energy will make it more difficult for the patient to achieve goals of disease prevention and weight reduction. In addition, physical inactive subjects are more negative to physical exercise than physically active subjects. However, physically inactive subjects must be informed that they can increase their maximal aerobic capacity by physical training rapidly. In addition, they must be informed that it takes 10-20 weeks of regular physical endurance training to achieve increased vitality and a more positive attitude towards physical activity, and furthermore, that it is necessary with physical endurance training 2-4 times on a weekly basis to maintain positive effects of physical training.