This research was carried out by researchers at Stanford University and funded by Apple. The study provided 110 Veterans Affairs patients with cardiovascular disease with iPhone 7 and Apple Watch Series 3. Patients regularly take a 6-minute walk test at home and compare it with standard outpatient 6MWT performance.
The study found that under clinical supervision, Apple Watch can accurately assess human weakness with a sensitivity of 90% and a specificity of 85%. When the assessment is carried out in an unsupervised environment at home, Apple Watch can accurately assess the degree of fragility of the body, with a sensitivity of 83% and a specificity of 60%.
The results of the study show that passive activity data collected by Apple Watch can accurately predict the performance of outpatient 6MWT.