Objective sleepiness without a subjective complaint decreases hypertension risk

Excessive daytime sleepiness has been associated with significant cardiovascular morbidity. Objective sleepiness, as measured by short sleep onset latency, has been associated with poor cognitive performance in otherwise healthy individuals who do not complain of excessive daytime sleepiness, but its association with cardiovascular morbidity has not been explored. Thus, we investigated the association of objective sleepiness without a complaint of excessive daytime sleepiness with hypertension risk in a large random general population sample.

From 1741 adults of the Penn State Cohort, 1590 individuals without a complaint of excessive daytime sleepiness were included in the cross-sectional analysis. From those, 659 subjects without hypertension were followed-up for an average of 7.5 years and were included in the longitudinal analysis. Objective sleepiness was defined as sleep onset latency ≤7 minutes during overnight 8-hour polysomnography. Prevalent hypertension was defined as either high blood pressure or medication use, whereas incident hypertension was determined by self-report of receiving treatment for high blood pressure. Binary logistic regression was performed while controlling for multiple potential covariates.

The prevalence and incidence of hypertension was significantly lower in individuals with objective sleepiness than control group (22.1 per cent vs. 32.3 per cent and 8.8 per cent vs. 17.3 per cent, respectively). Objective sleepiness was less likely to be associated with prevalent (OR = 0.44; 95%CI = 0.23 to 0.81; p = .010) or incident (OR = 0.31; 95%CI = 0.10 to 0.96; p = .043) hypertension, respectively, compared to control group. The combination of objective sleepiness with subjective excessive daytime sleepiness eliminated the protective effect on hypertension risk.

Our novel and unexpected findings suggest that objective sleepiness without excessive daytime sleepiness has a protected effect against hypertension risk, a useful finding for practicing clinicians in assessing hypertension risk in their patients. Statement of Significance This is the first longitudinal study, based on a large random general population sample, that showed that objective sleepiness without a complaint of excessive daytime sleepiness (EDS) is associated with a significantly reduced risk of prevalent and incident hypertension. Subjective EDS is highly prevalent in the general population and has been associated with significant cardiovascular morbidity and mortality. Objective sleepiness without the complaint of EDS has been associated with poor cognitive performance, but its association with cardiovascular morbidity is unknown. This study's novel and unexpected findings suggest that individuals who fall asleep quickly and do not complain of daytime sleepiness are protected from cardiovascular problems. The importance of this finding is underlined by the high prevalence of objective sleepiness, i.e. 10 per cent in the general population.