Aortic Stiffness and Hemodynamics in Young Adults with Isolated Nocturnal Hypertension

Introduction: Up to 20% of young adults exhibit high blood pressure (BP) during sleep, or nocturnal hypertension. Emerging evidence suggests that individuals with nocturnal hypertension are at risk of cardiovascular diseases (CVD); however, the underlying pathophysiological mechanisms remain unclear. To our knowledge, there is no study investigating whether nocturnal hypertension in young adults is associated with changes in aortic stiffness and hemodynamics, both of which are known contributors to the development of CVD. Objective: This study aims to compare aortic stiffness and hemodynamics in young adults with and without isolated nocturnal hypertension. Hypothesis: We hypothesize that compared to young adults without isolated nocturnal hypertension, young adults with isolated nocturnal hypertension would have increased aortic stiffness, higher aortic BP, enhanced aortic wave reflection, and elevated aortic pulse pressure pulsatility. Methods: A total of 69 young adults (34 males and 35 females; age: 26±4 yrs, body mass index: 24.0±2.8 kg/m 2 ), free of clinical diseases and smoking, were included in this study. All participants had in-laboratory seated BP < 130/80 mmHg (systolic BP [SBP]: 110±8 mmHg and diastolic BP [DBP]: 66±6 mmHg). Nocturnal hypertension is defined as nighttime BP ≥110/65 mmHg, assessed by 24-hr ambulatory BP monitoring. After a 10-min supine rest in the laboratory, carotid-femoral pulse wave velocity (cfPWV, a measure of aortic stiffness) and aortic hemodynamics including BP, forward and backward pressure wave amplitude (Pf and Pb, respectively), and pulse pressure (PP) were assessed using SphygmoCor XCEL. cfPWV normalized by mean arterial pressure (cfPWV/MAP), aortic reflection magnitude (RM, a ratio of Pb to Pf) and aortic pulsatile load (APL, a product of aortic PP and heart rate) were calculated. Results: Compared to young adults without nocturnal hypertension (n=46; 39.1% men), young adults with isolated nocturnal hypertension (n=23; 69.6% men) had higher aortic SBP (+8 mmHg, P< 0.001 for group effect and P=0.18 for sex by group interaction), higher aortic DBP (+5 mmHg, P=0.007 for group effect and P=0.33 for sex by group interaction), higher Pb (+2 mmHg, P=0.002 for group effect and P=0.55 for sex by group interaction), as well as higher RM (+3.6%, P=0.043 for group effect and P=0.80 for sex by group interaction). No between-group differences were found in cfPWV (P=0.21), cfPWV/MAP (P=0.27), Pf (P=0.57), PP (P=0.11), and APL (P=0.46). Conclusions: Our data indicate that young adults with isolated nocturnal hypertension had higher aortic BP and wave reflection amplitude, but similar aortic stiffness and pulse pressure pulsatility compared to young adults without isolated nocturnal hypertension. Funding: This work was supported by the Texas Chapter of the American College of Sports Medicine to student PI (KYC). This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.