Pedometers -- those little devices worn at the waist to count steps -- are popular tools for documenting activity levels, and it's now been documented that their use can help motivate users to increase their exercise levels. Dr. Dena M. Bravata and colleagues at Stanford University Medical School (JAMA 2007;298:2297) combined and evaluated data from twenty-six studies of the effects of pedometer use on activity levels and various health indices.
There were a total of 2,767 participants in the various studies reviewed: 85% were women. On average they were forty-nine years old and were studied for an average of eighteen weeks. Overall, the researchers found, pedometer users increased their physical activity by nearly 27% over their typical baseline levels. This was equivalent to an extra 2,000 steps or one mile per day.
When the results of all studies were combined, the pedometer users significantly decreased their body mass index (BMI), by 0.38, and their systolic blood pressure (the upper number), by 3.8 mm Hg -- this was true even though the majority of the participants weren't hypertensive when the study began. The people who benefited the most from using pedometers seemed to be those who were given a step goal to reach, such as 10,000 steps per day -- whether they actually reached the goal or not. Also, when participants were required to keep a diary of their activity level, they tended to increase steps more than participants who did not have that requirement.
Because not all the studies determined food intake, the authors of the review were unable to tell if the altered activity levels also affected dietary intake. They also noted that since their subjects were primarily adult women, it was not clear to what extent their results could be generalized to men or to individuals of other ages.
Since the studies they reviewed were somewhat heterogeneous, Dr. Bravata and colleagues suggested that future studies are necessary to confirm whether participants' performance is affected by several factors -- such as having a step goal, being able to see (or being unaware of) the number of steps they take, and keeping step diaries. This is likely a reasonable suggestion, but even before such studies are completed, it is certainly sensible to suggest that people who want to improve health try the pedometer technique -- after getting an OK from their healthcare provider, of course.
Ruth Kava, Ph.D., R.D., is Nutrition Director at the American Council on Science and Health (ACSH.org, HealthFactsAndFears.com).
