Smartphone-based 6-Minute Walking Test While Walking in the Park: Bringing Physical Fitness Monitoring to the Patient's Hands.

In recent years, patient care has partially shifted from the hospital to the patients’ homes.1 This evolution is also seen in cardiac rehabilitation, in which a growing number of patients is participating in cardiac telerehabilitation programmes. At present, a limiting factor in offering fully remote care is the need for assessing and reassessing the patient’s physical fitness at predefined intervals in order to adjust the training programme. Currently, assessing physical fitness is done by either performing a cardiopulmonary exercise test (CPET), which assesses maximal exercise capacity, or a 6-min walking test (6 MWT), which assesses submaximal exercise capacity.2 This study aimed to investigate a new tool that allows patients to self-test their submaximal exercise capacity in a flexible way by a smartphone-based random walk 6 MWT. This study is a subanalysis of a study that was previously published by our group.3 In this paper, multiple algorithms were used for performing the 6 MWT, and the best algorithm was determined. This best algorithm is the algorithm that is used for this sub-analysis. The study demonstrated that an algorithm based on the Google Fit step count with the smartphone worn in a strap around the patient’s arm performed the best when considering both accuracy and reliability.3