Purpose: The effects of self-monitoring number of steps/day versus minutes of moderate to vigorous-intensity physical activity (MVPA/day) were compared to determine which is more effective for increasing physical activity levels.
Methods: A total of 18 participants of a university-based chronic disease prevention program (age 61 +/- 12 years) were enrolled in the 3-week intervention. Subjects were randomly assigned to a group (n = 8) that wore a New Lifestyles accelerometer (NL-1000) and were instructed to increase minutes of MVPA to 30 min/d or more (MIN) or to a group (n = 10) that wore a New Lifestyles pedometer (NL-800) and were instructed to increase the number of steps/day to 10,000 or more (STE). To objectively assess changes in physical activity levels, subjects in both groups simultaneously wore a Lifecorder-EX accelerometer (with display blank) during the intervention.
Results: The number of steps increased significantly in the MIN (10,810 +/-3,211 to 13,355 +/- 3,498 steps/day) and STE (11,517 +/- 3,383 to 12,809 +/-2,479 steps/day) from the first to fourth weeks, respectively. However, the time spent in MVPA increased significantly only in MIN group (36 +/- 11 to 52 +/- 15 min/d) but not in the STE group (32 +/- 7 to 37 +/- 11 min/d) from the first to fourth weeks, respectively.
Conclusion: Data suggest that individuals with chronic disease conditions can more effectively increase levels of physical activity, expressed as both MVPA/day and steps/day, by self-monitoring MIN rather than STE. The effect of self-monitoring physical activity levels for longer periods and/or the effect of increasing minutes of MVPA/day versus steps/day on specific health outcomes have not yet been examined.