Validity of the Past-day Adults' Sedentary Time Questionnaire in a Cardiac Rehabilitation Population

Purpose: Self-report measures of sedentary behavior are easier to use in a clinical setting; yet, no self-report measures of sedentary behavior appear to be validated in cardiac rehabilitation over time. The aim of this study was to assess the validity of the Past-day Adults' Sedentary Time (PAST) questionnaire in a cardiac rehabilitation population over 12 mo. Methods: Seventy-two cardiac rehabilitation participants were recruited to a prospective cohort study. Participants wore an ActiGraph ActiSleep accelerometer (sedentary time <100 counts/min) for 7 consecutive days and completed the self-administered PAST questionnaire at baseline, 6 wk, and 6 and 12 mo. Total daily sedentary time from both methods were compared using Bland-Altman plots and Spearman rank-order correlations. Results: Agreement between the 2 measures of sedentary time improved over 12 mo. At 6 and 12 mo, there was a good level of agreement between measures (mean difference between accelerometer and PAST 57 and -0.7 min, respectively), although the dispersion of the differences was wide (95% limits of agreement -428 to 541 and -500 to 498 min, respectively). There were weak correlations between the PAST questionnaire and average accelerometer measured sedentary time at all time points (alpha = -0.249 to 0.188). Conclusions: Following repeated assessments, the PAST questionnaire may be useful to determine sedentary time in cardiac rehabilitation participants at a group level, with participants appearing to more accurately recall their time spent in sedentary behavior. Further research is indicated to assess the validity of sedentary behavior questionnaires in cardiac rehabilitation, with a combination of objective and self-reported measures currently recommended.