Assessment of functional capacity and sleep quality of patients with chronic heart failure

Adequate sleep improves physical and mental alertness. However, there is a dearth of empirical data on functional capacity (FC) and sleep quality (SpQ) in patients with chronic heart failure (CHF).

This study investigated the relationship between FC and SpQ of patients with CHF and apparently healthy controls (HCs).

This case-control study recruited 50 patients with CHF whose left ventricular ejection fraction (LVEF) was <40%, attending cardiac clinics of selected government hospitals in Osun State. Furthermore, 50 age- and sex-matched healthy individuals were recruited as controls. Socio-demographic characteristics and cardiovascular parameters were assessed. The FC (VO₂ max) and SpQ were assessed using the 6-minute walk test (6-MWT) and Pittsburgh Sleep Quality Index (PSQI), respectively. Data were analysed using descriptive and inferential statistics. Alpha level was set at p < 0.05.

Patients had a significantly lower FC and poorer SpQ than HCs, 4.6 ± 0.5 versus 11.3 ± 1.6 mL/kg/min (t = -3.452; p = 0.001) and 8.74 ± 1.6 versus 3.8 ± 1.3 (t = -5.371; p = 0.001), respectively. HCs were about five times more likely to walk longer distance [odds ratio (OR), 4.8; confidence interval (CI), 2.0-11.1] and had a better heart rate (OR, 2.8; CI, 1.4-5.3) than patients. SpQ had a significant negative correlation with FC of patients (r = -0.362; p = 0.001) but a significant positive correlation with HCs (r = 0.481; p = 0.041). Furthermore, there were significant correlations between FC and body mass index in both groups (CHF: r = 0.247, p = 0.022; HCs: r = 0.321, p = 0.040).

Patients with heart failure demonstrated lower functional capacity and poorer sleep quality.