[German National Physical Activity Recommendations for Adults and Older Adults: Methods, Database and Rationale].

National physical activity recommendations are regarded as crucial elements of comprehensive physical activity promotion strategies. To date, Germany has no such national physical activity recommendations. The aim of this study was to provide physical activity recommendations based on a comprehensive summary of scientific evidence on the relationships between physical activity and a range of health outcomes in adults and older adults. The recommendations were developed in a 3-phase process (systematic literature review, development and use of quality criteria, synthesis of content) based on already existing high-quality guidelines. Based on the analysis of documents included in this study, the following recommendations were formulated. To gain wide-ranging health benefits, adults and older adults should be physically active regularly and avoid inactivity. Adults and older adults should carry out at least 150 min/week moderate intensity or 75 min/week high intensity aerobic activity. Adults and older adults can also reach the recommended amount of physical activity by performing activities in an appropriate combination in both intensity ranges. Optimally, physical activity should be distributed over the week and it can be accumulated in bouts of at least 10 min. Physical activity beyond 150 min/week yields further health benefits. At the same time, physical activity below 150 min/week is associated with meaningful health gains. Accordingly, all adults and older adults should be encouraged to be physically active whenever possible. Adults and older adults should also perform muscle strengthening activities at least twice a week. Regular balance exercises (3 times a week) can reduce the risk of falls in older adults. Adults and older adults should avoid long periods of sitting and should break up sitting time by physical activity. Physical activity can lead to adverse events, such as musculoskeletal injuries, which can be mitigated through appropriate measures. All in all, the benefits of regular physical activity overweigh by far the risks in both adults and older adults.