[Validity of the PEDOMETER® mobile application for evaluating cardiorespiratory fitness and fatigue resistance in cardiac rehabilitation. A pilot study].

Background: A mobile application (app) may facilitate the administration of the 6-minute walk test (6MWT), a commonly used tool in cardiac rehabilitation. This pilot study, conducted with cardiac rehabilitation patients, aimed to evaluate: 1) the criterion validity of the PEDOMETER® app compared to the 6MWT in assessing cardiorespiratory fitness and fatigue resistance, and 2) the construct validity of the PEDOMETER ® app in relation to the Hospital Anxiety and Depression Scale (HADS) and the Health Index of the EuroQol-5D 3L questionnaire (EQ-5D).

Methods: Twenty patients undergoing cardiac rehabilitation at HM Puerta del Sur Hospital (Mostoles, Spain) performed the 6MWT while using the PEDOMETER ® app on a smartphone worn on their arm. Pearson's correlation coefficient was calculated to assess the relationship between the distance recorded in meters during the 6MWT and that recorded by the app, as well as between the app and the anxiety and depression dimensions of the HADS, and the Health Index EQ-5D.

Results: The criterion validity of the 6MWT and the PEDOMETER ® app was excellent (r = 0.981; p < 0.001). Regarding construct validity, the app showed a moderate negative correlation with the depression dimension of the HADS (r= -0.493), but not with the anxiety dimension or the EQ-5D.

Conclusions: The free PEDOMETER ® app demonstrates excellent criterion validity when compared to the 6MWT. The app shows a moderate negative correlation with the depression dimension of the HADS.