Device-measured physical activity, sedentary time, and sleep in patients with arrhythmogenic cardiomyopathy: descriptive values and stability over 30 measurement days

Introduction Regular exercise and sports are contraindicated in arrhythmogenic cardiomyopathy (AC) patients, which might lead them to an unhealthy sedentary lifestyle. This study aimed to objectively describe the patterns of physical activity (PA), sedentary time (SED), and sleep in patients with AC, and to examine the reproducibility of accelerometer-derived measures over four consecutive weeks. Methods A total of 71 (49.6 [SD=17.5] years) patients with AC wore a wrist-worn Axivity AX3 accelerometer for 30 consecutive days to monitor their physical activity, sedentary time, and sleep habits. The reproducibility of each metric across the 4 assessment weeks was assessed with the intraclass correlation coefficients (ICCs) derived from linear-mixed models adjusted for age, body mass index (BMI), and season. Results The participants spent a median of 12.2 [IQR 2.1] h/d in SED, 6.4 [IQR 1.0] h/d sleeping, and 17.9 [IQR 24.5] min/d in moderate-to-vigorous physical activity (MVPA), and 59% of the participants did not reach the 150 min/d of MVPA recommended by the WHO for people living with chronic disease. No significant differences in PA were found by sex and age groups. Otherwise, patients aged ≥50 years (n= 33) spent 38.9 min/d (95% CI 5.8 to 72.2, p≤0.05) more in periods of ≥30 minutes of SED than those <50 years. Participants with obesity (n=10) accumulated 66.6 min/d (95% CI 5.2 to 128.1, p = <0.05) more SED in periods of ≥30 minutes and 22.8 min/d (95% CI 0.7 to 44.9, p≤0.05) less MVPA than those without obesity. The ICCs ranged from 0.67 for time in bed to 0.92 for light-intensity physical activity using a 7-day assessment period. However, the ICCs increased from 0.03 for LPA to 0.18 for time in bed when an assessment period of 14 days was chosen. Conclusion Patients with AC engage in large periods of SED, insufficient PA and sleep. Importantly, nearly 60% of the participants did not meet the minimum amount of PA recommended by the WHO for people living with chronic diseases and only 20% met the sleep recommendations. Device-measured PA and SED are stable across weeks, indicating that a 7-day assessment period might provide a reproducible measure of PA and SED and, to a lower extent, sleep.