Can pedometer data contribute to observing Public Health Physical Activity Guidelines?

Background. Some suggest that pedometer/accelerometerss encourage people to meet recommended daily minimum levels of habitual physical activity, but others find little relationship between pedometer counts and the meeting of activity targets. Purpose. To review the practical value of pedometer/accelerometers in assessing current behaviour and encouraging greater physical activity. Methods. Pedometer/accelerometer counts corresponding to minimum desirable levels of physical activity are examined, and the validity of individual estimates of activity levels is evaluated critically in the context of specific observations by White and associates. Alternative methods of monitoring physical activity are considered, and the motivational impact of wearing a pedometer/accelerometer is explored. Results and Conclusions. Estimates based on both theoretical considerations and the relationship of step counts to health outcomes suggest that largely sedentary individuals achieve counts of at least 4000 steps/day. Counts of at least 7000 steps/day are needed to meet minimum health objectives, and values up to 10,000 steps/day should be encouraged. Pedometer/accelerometers are relatively accurate when assessing activity levels on a treadmill or a track, but they paint a less accurate picture in normal daily life; they do not reflect such activities as hill climbing, swimming, cycling and resistance exercise. One study of arthritic patients found little relationship between individual counts and achievement of activity goals. Multiphasic monitors to date offer little advantage over simpler pedometer/accelerometers. The wearing of an activity monitor stimulates physical activity, and if specific goals are set this increase persists for at least 4 months. However, longer-term studies of health-promotional value are still required.