Measuring habitual physical activity in adults with cystic fibrosis

The aim of the present study was to determine whether different methods of recording physical activity (PA), i.e., accelerometers vs questionnaires, provided similar information in adults with cystic fibrosis (CF).

20 CF (age 33 ± 8SD yrs, FEV1 68 ± 16% predicted) and 11 age-matched healthy controls completed the Habitual Activity Estimation Scale (HAES) questionnaire and wore a biaxial accelerometer (SenseWear Pro3 Armband). Exercise tolerance was measured in CF.

Patients had similar values in PA compared with controls. None of PA categories estimated by HAES questionnaire correlated with PA categories measured by the accelerometer; in CF the HAES questionnaire overestimated the effective levels of PA measured by the accelerometer. There were no differences between weekdays and weekend days PA levels provided by the accelerometer. In CF the questionnaire detected different time reported during the "somewhat inactive" and "somewhat active" categories (z = 2.651; p = 0.008; z = -2.651; p = 0.008), weekdays vs weekend; patients reported more time spent in activity (somewhat active & very active) during the weekend (z = -2.203; p = 0.02). Peak oxygen uptake correlated with accelerometer activities of "moderate" (>4.8 metabolic equivalents (METS)) and "vigorous" (>7.2 METS) intensity (r = 0.503, p = 0.02; r = 0.545, p = 0.01).

In adults with cystic fibrosis PA levels are better evaluated by the accelerometer and are similar to the controls. PA measured by the accelerometer is similar during the week and correlates with exercise tolerance.