Poor Agreement between Responses to the International Physical Activity Questionnaire and Objective ActiGraph ® Data among Persons with Major Depressive or Bipolar Disorders

The purpose of this research was to investigate the degree of agreement between data from the International Physical Activity Questionnaire—Short Form (IPAQ) and accelerometer (ActiGraph ® ) readings for physical activity (PA), classified as moderate, vigorous, and moderate–vigorous PA, and sedentary behavior (SB) in participants with major depressive or bipolar disorder. Following a cross-sectional observational design ( n = 30), participants used an accelerometer for 4 to 7 days (minimum of 10 h per day) and answered the IPAQ (for the same period as accelerometer use). Our results suggest significant differences ( p < 0.05) when comparing the ActiGraph ® and IPAQ data: for moderate PA, 155 min vs. 25 min per week; for moderate–vigorous PA, 157 min vs. 50 min per week; and for SB, 8 h vs. 3 h per day. Spearman’s correlation coefficients (ActiGraph ® and IPAQ) were low for moderate PA, vigorous PA, and moderate–vigorous PA (rho = 0.03 to 0.13). The Bland–Altman plot showed a bias of −75 min for moderate PA, 9 min for vigorous PA, −66 min for moderate–vigorous PA, and −5 h for SB. Considering the differences observed and the objectivity of the ActiGraph ® measurements, whenever possible, we recommend ActiGraph ® measurements of PA and SB for these clinical groups.