Measuring long-term physical activity in patients with heart failure and its relation to health-related outcomes.

AIM: Current physical activity guidelines often rely on self-reported or short-term device-based monitoring. We analysed long-term activity data via acceleration and continuous optical heart rate measurement and hypothesised a temporal association between volume and intensity and health-related outcomes in heart failure. METHODS: This prospective observational trial reanalysed longitudinal data from 156 patients with heart failure at baseline, 6 months, and 12 months. A multisensory activity tracker captured daily step count and continuous heart rate data over a 1-min sampling interval from patients with New York Heart Association (NYHA) Class I (n = 66) and Class II/III (n = 90) over 12 months. Linear mixed-effects models and univariate linear regression models were used to assess the associations between step count, moderate physical activity (MPA) and vigorous physical activity (VPA) and health-related outcomes [cardiorespiratory fitness, body composition, systemic inflammation levels, N-terminal pro brain natriuretic peptide (NTproBNP), and Kansas City Cardiomyopathy Questionnaire (KCCQ)]. RESULTS: Patients with NYHA I and NYHA II/III spent a median (interquartile range) of only 225 (105;412) vs 167 (72;326) min per week with MPA, 17 (7;44) vs 9 (4;23) min per week with VPA, and 8021 (6474;9910) vs 6438 (5181;8627) steps per day, respectively. VPA was positively associated with maximum oxygen uptake (ml/kg/min) (VO2max; β=3.815, 95% CI [1.430-10.186], P = .008), and MPA was inversely associated with NT-proBNP (pg/ml) (β=-0.189, 95% CI [-0.353 to -0.025], P = .024). For step count, a positive association with VO2max (ml/kg/min) (β=0.545, 95% CI [0.295-0.795], P < .001), and a negative association with fat mass (%) (β=-1.058, 95% CI [-1.441 to -0.674], P < .001), C-reactive protein (mg/l) (β=-0.057, 95% CI [-0.097 to -0.017], P = .005), and interleukin-6 (pg/ml) (β=-0.022, 95% CI [-0.043 to -0.001], P = .041) was observed. Absolute changes (Δ) for improved VO2max (ml/kg/min) (r = 0.197, P = .043) and reduced fat mass (%) (r = 0.205, P = .014) were associated with VPA between baseline and 12 months. No relationship was found with KCCQ. CONCLUSIONS: Long-term device-based physical activity monitoring showed that patients with heart failure met recommendations for MPA, yet vigorous activity exceeding 60% of heart rate reserve was almost entirely absent. Higher aerobic physical activity was associated with greater VO2max, lower fat mass, reduced systemic inflammation (C-reactive protein and interleukin-6), and lower NT-proBNP, but not with KCCQ, whereas only VPA, unlike MPA, was associated with higher VO2max and lower fat mass.