Objective:To assess the effect of smartphone applications designed for physical activity tracking on exercise tolerance of patients with arterial hypertension (HTN) and coronary artery disease (CAD) during rehabilitation program.Design and method:We examined 464 patients with HTN (men 176, 37.9%) aged 61.7 ± 11.0 who attended rehabilitation programs in 5 days to 6 months after myocardial infarction (median 24 [6; 92] days) in health campus. Most of the patients undergone coronary revascularization: 371 (80.0%) - percutaneous coronary intervention and 75 (16.1%) coronary artery bypass grafting; 18 patients (3.9%) had non-invasive management. Patients were randomized in two groups: I (n = 238, 51.3%) were using mobile apps with activity trackers and II (control, n = 226, 48.7%) without intervention. The six-minute walk test (6MWT) was performed at the time of admission, in the middle of the rehabilitation course (the 6th day) and before discharge (the 12th day) (6MWT1, 6MWT2 and 6MWT3, respectively). We compared groups using Mann-Whitney U test and assessed changes in 6MWT distance as the difference between measurements (6MWT2-1 = 6MWT2 – 6MWT1 and 6MWT3-1 = 6MWT3 – 6MWT1).Results:The 6MWT1 distance on admission did not differ between the experimental and control groups (440.1 ± 82.3 m vs 421.3 ± 78.1 m, p = 0.81). The 6MWT distance increased over time in both groups. In the middle and at the end of the course difference between the groups became statistically significant: 6MWT2 in I group 499.3 ± 88.5 m vs 446.0 ± 82.7 in group II, p < 0.001; 6MWT3 was 570.6 ± 89.5 m vs 473.6 ± 88.3 m, respectively, p < 0.001. Experimental group had a more pronounced increase in 6MWT after the 2nd measurement (6MWT2-1 59.1 ± 26.3 m vs 25.6 ± 17.7m, p < 0.001) and the 3rd measurement (6MWT3-1 was 130.5 ± 45.2 m vs 52.5 ± 30.6 m, p < 0.001).Conclusions:The use of mobile apps for physical activity tracking in patients with HTN and CAD after MI was associated with an increase in the 6MWT distance on the 6th and 12th day of cardiac rehabilitation program compared with the control group.