Validation of the 24-hour physical activity recall in elderly adults

The objective of this study was to verify the validity of the 24-hour physical activity recall (R24AF) and to evaluate the number of days required to estimate weekly physical activity using the R24AF in elderly adults. A methodological validation study with a cross-sectional design was carried out. Thirty elderly adults used accelerometers (reference standard) and answered the R24AF by telephone for seven consecutive days. Data were analyzed using the following tests: Pearson's correlation to compare minutes of physical activity between methods; the McNemar test to verify agreement between methods regarding health-oriented physical activity recommendations (≥150 min/week); graphical analysis using the Bland-Altman method; the t-test for dependent samples to detect differences in minutes of physical activity between methods; and the Kappa test to determine the number of days of R24AF use required to estimate weekly physical activity, with the seven days assessed by accelerometers serving as a reference. The correlation coefficient ranged from r=0.38 (p=0.002) to r=0.60 (p