Forty nights of sleep were sampled from 20 inpatients, who had a mean age of 72.4 years (SD 7.5), mean BMI 25.4 m/kg2 (SD 6.7), and a median length of stay of 7 days (IQR = 3.0–9.3). Twelve were male, and 9 were African American. Patients had few comorbidities: 5 chronic obstructive pulmonary disease, 3 congestive heart failure, 1 end stage renal disease, and 5 diabetes.
On average, in-hospital sleep duration was 2.5 hours shorter (277 min, SD = 107) than self-reported habitual sleep (427 min, SD = 113 min; p<0.001). In-hospital sleep efficiency was very low [66.0% (95% CI 59.0–73.0)], with 67.5% of nights below the clinical threshold for insomnia (80% efficiency). Compared to matched community controls, mean in-hospital sleep duration was 2 hours shorter (−120 minutes, 95% CI −179.2, −61.8; p=0.005) and sleep efficiency was 14% lower (95% CI −25.3, −2.7; p=0.020) in hospitalized seniors.
Mean systolic blood pressure was 142.1 mmHg (95% CI 136.2–147.9) and mean diastolic blood pressure was 70.0 mmHg (95% CI 66.5–73.4). In-hospital sleep and systolic blood pressure were inversely correlated (r= −0.46, p=0.003). Patients in the highest tertile of sleep duration (mean 398 min 95% CI 367, 423) had an average blood pressure of 130 mmHg (95% CI 118, 141) while those in the lowest tertile of sleep duration (mean 166 minutes 95% CI 131, 200) had a blood pressure that was over 20 points higher (152 mmHg 95% CI 138, 165) (p=0.015 by trend test). This relationship remained significant in multivariate analyses. For each hour of inpatient sleep loss, systolic blood pressure increased by 6.2mmHg (95% CI 3.2 to 9.2, p<0.001) (). Likewise, each 10% decrease in sleep efficiency was associated with an increase in systolic blood pressure of 4.2mmHg (95% CI 1.6 to 6.9, p= 0.002). Multivariate, but not univariate, regression models demonstrated that each hour of sleep loss was associated with an increase of 3.1mmHg (95% CI 1.6 to 4.6, p<0.001) in diastolic blood pressure. No association between sleep efficiency and diastolic blood pressure was observed.
Association between Systolic Blood Pressure and Sleep Duration for Hospitalized Seniors
Mean global vigor in this cohort (65.8) was slightly higher than in previous studies of normal middle aged controls (59.0), while mean global affect scores (70.4) were equivalent to the prior studies (68.3).10
We did not find an association between hours of inpatient sleep loss and global vigor score [ΔGV −0.9 (95% CI −4.4, −2.5) p=0.60]. Each hour of sleep loss was associated with a statistically significant but minimal elevation in global affect score [Δ GA +2.2 (95% CI 0.1, 4.3) p=0.04].