Presence and duration of reactivity to pedometers in adults

PURPOSE: To examine the presence and duration of reactivity to wearing a pedometer and recording daily step counts in free-living adults. METHODS: On the first visit to the laboratory 90 participants (69% female, age = 26.8±13.0 years, BMI = 23.4±4.0 kg/m2), blinded to the study aim, were provided with a sealed pedometer (New Lifestyles NL-800) and informed that it was a 'Body Posture Monitor' (covert condition). Participants wore the pedometer throughout waking hours for 1 week. Upon return to the laboratory, stored step counts were recorded and participants were informed that the device was a pedometer. Participants wore the pedometer unsealed (no restriction on viewing the step count display) for 2 weeks, during which they recorded their daily step count in a diary (diary condition). Mean daily step counts recorded during the covert condition and during weeks 1 and 2 of the diary condition were compared using a repeated-measures ANOVA. RESULTS: There was a significant overall effect of study condition (P<0.001), with post hoc analyses revealing that mean daily step counts reported during the first week of the diary condition (9898±3002 steps/day) were significantly higher than those reported during the covert condition (8331±3010 steps/day) and during the second week of the diary condition (8226±3170 steps/day) (P<0.001). CONCLUSION: Reactivity to wearing unsealed pedometers and step count recording appears to last for 1 week. In the absence of any intervention material, step counts return to normal levels during the second week of monitoring, and therefore represent a more accurate estimate of habitual activity. These findings have important implications to both researchers and practitioners interested in the use of pedometers for physical activity surveillance and promotion.