Comparison of pedometer and activity diary for measurement of physical activity in chronic obstructive pulmonary disease.

ABSTRACT

PURPOSE: Precise, inexpensive tools for measuring physical activity levels are important for developing strategies to improve symptoms and enhance quality of life in chronic obstructive pulmonary disease (COPD). Self-report questionnaires and diaries have been used in many populations with variable results. The pedometer is widely recognized as a valid and reliable objective measurement tool, but it has not been well tested in COPD. This study aimed to determine the relationship between free-living physical activity recorded in a daily diary and that measured by using a pedometer in patients with COPD. METHODS: Participants with COPD (n = 80) recorded physical activity over 7 days. Cumulative pedometer readings and diary records of 4 activity categories for each 0.5 hour were compared. RESULTS: Participants (n = 76) with complete data sets were included in the analysis. The diary was more reliably completed. Mean pedometer reading per week was 23,129 (SD = 17,083) "step" counts (range, 1,725-66,454). Mean diary-recorded standing and walking time per week was 98.9 (SD = 10.4) hours (range, 73-119.5). The relationship between these measures was moderate and statistically significant (r = 0.37, P = .001). CONCLUSIONS: A daily diary record appears to offer more promise than the pedometer as a tool for measuring free-living physical activity in patients with COPD. Further research is required to assess the value of the 2 methods as discriminative, evaluative, and predictive tools in COPD populations.