LAUSR

OBJECTIVE Recent community-based studies have identified sleep deprivation (SD) as an important modifiable risk factor for hypertension However, the underlying mechanisms linking SD to hypertension remain elusive. Thus, this study investigates blood pressure (BP) responses to cardiac autonomic stress tests in the presence of SD. Furthermore, we analyzed vascular inflammatory biomarkers as a possible underlying factor linking SD to increased BP. METHODS Ten healthy male volunteers (age, 21.6±1.2 years) underwent repeated autonomic stress tests for three consecutive days (baseline, SD, and recovery). The autonomic stress tests included the Valsalva maneuver, mental arithmetic, isometric handgrip, and cold pressor tests. Each day, resting BPs were measured, venous blood samples were collected for intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and E-selectin measurements, and stress tests were performed between 0900 and 1100. Ambulatory BP was recorded during the entire SD period (24 h). RESULTS One-night SD abolished BP reactivity to the Valsalva maneuver, isometric hand grip, and cold pressor tests, which returned after recovery sleep. Ambulatory BP monitoring showed that the mean systolic and diastolic BPs were 121.1±8.5 mm Hg and 72.8±6.3 mm Hg, respectively, between 0700 and 2300 and 120.3±9.6 mm Hg and 74.1±6.1 mm Hg, respectively, between 2300 and 0700 during the SD day (p>0.05 for both). Vascular inflammatory markers seemed unrelated to BP changes. CONCLUSION Acute SD altered BP responses to cardiac autonomic stress tests in healthy men without affecting resting BP levels. SD led to a non-dipping pattern in BP oscillation. Collectively, these findings highlight the importance of sleep in regulating BP.