Physical activity is strongly associated with good health and in contrast physical inactivity is an independent risk factor. From the pathogenetic point of view there are strong correlations between physical inactivity and abdominal fat mass thus leading to numerous diseases of civilization. Calorie turnover by physical activity shows a strong dose-response relationship to the incidence and mortality of diseases of civilization, especially of coronary heart disease. Activities of daily living contribute slightly to the daily calorie turnover and can be documented by accelerometers. The number of steps per day is not only a parameter allowing a different inside view to daily routines but is also a key for interventional programs. Enhancing the number of steps per day to 10,000, the internationally accepted threshold for an active lifestyle, causes a remarkable augmentation in health status. From the therapeutic point of view, increasing the number of steps lowers the incidence of diabetes type 2 and also affects the disease pattern.