Exercise is good for us, especially as we get older.1, 2 People who are regularly active enjoy a lower risk of osteoporosis and a much reduced risk of coronary heart disease (the vigorously active have about half the risk of the inactive). Most people in Britain are not taking enough exercise to achieve these health benefits.3, 4

If primary health care teams could increase their practice populations' physical activity then many benefits might follow, including lower rates of cardiovascular disease, fewer fractured hips, reduced depression and anxiety, and improved functional ability in elderly people. Although this list makes promotion of healthy exercise look tempting, primary health care teams, and the policymakers who determine allocation of resources, should look carefully before they leap.

Very little is known about the effectiveness of exercise programmes and other initiatives designed …