RESUMO
PURPOSE: Poor sleep quality has an unfavorable impact on autonomic nervous system activity, especially that of the cardiovascular (CV) system. The heart rate (HR) and blood pressure (BP) at rest and during exercise, along with the heart rate recovery (HRR), were examined in poor sleepers and compared with individuals with good sleep quality. METHODS: A total of 113 healthy individuals were enrolled to the study. All participants performed treadmill stress testing. Sleep quality of participants was assessed by using the Pittsburgh Sleep Quality Index (PSQI) questionnaire: 48 subjects were categorized as 'poor sleepers' (PSQI score > 6 points), and the rest were grouped as 'good sleepers'. RESULTS: The poor sleepers showed higher resting HR (p <0.001), higher diastolic BP (p=0.006), similar systolic BP (p=0.095), more frequent hypertensive response to exercise (p=0.046) and less HR increase with exercise (chronotropic incompetence) (p=0.002) compared with individuals who reported good sleep quality. In addition, the poor sleepers demonstrated reduced heart rate recovery at the 1st and 3rd minute of recovery (p=0.005 and 0.037, respectively) compared with good sleepers. Multivariate logistic regression analysis revealed that only resting diastolic BP was the independent predictor of HRE. The PSQI score was positively correlated with resting HR; while it was negatively correlated with HR response to exercise, HRR1 and HRR index-1. CONCLUSION: This cross-sectional study emphasizes the effect of poor sleep quality on unfavorable cardiovascular outcome indicators of the treadmill stress test.
