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<0.001) when comparing minutes of physical activity between methods, according to intensity. At least four days of R24AF use were necessary to obtain an adequate estimate of weekly physical activity (Kappa=0.51, p=0.005), and the estimated prevalence of active elderly was similar with four days' use of the R24AF and seven days' use of accelerometer. The R24AF proved valid for the evaluation of low and moderate physical activity in the elderly and requires at least four days of use (three week days plus one weekend day) to determine the pattern of weekly physical activity in the elderly.
Elderly; Motor activity; Validation studies
