Resting beat-to-beat blood pressure variability is preserved in young adults with major depressive disorder

Major depressive disorder (MDD) often first emerges during young adulthood and is associated with an increased risk of future hypertension, but our understanding of blood pressure (BP) regulation in young adults with MDD who are otherwise clinically healthy remains limited. We tested the hypothesis that beat-to-beat BP variability (BPV) would be greater in young unmedicated adults with MDD compared with nondepressed healthy adults (HA). Because the arterial baroreflex is essential for beat-to-beat BP regulation, we also hypothesized that <i>1</i>) sympathetic baroreflex sensitivity would be reduced in young adults with MDD and <i>2</i>) positively related to BPV. Beat-to-beat BP (finger photoplethysmography), heart rate (ECG), and muscle sympathetic nerve activity (MSNA; peroneal microneurography) were measured during 10-20 min of supine rest in 40 young adults with MDD (unmedicated; <i>n</i> = 19 females) and 27 HA (<i>n</i> = 17 females). There were no group differences in either resting BP (116 ± 10/73 ± 6 HA vs. 113 ± 9/74 ± 6 mmHg MDD; both <i>P</i> > 0.05) or MSNA (26 ± 11 vs. 24 ± 13 bursts/100 heartbeats MDD; <i>P</i> = 0.50). Neither beat-to-beat BPV (e.g., systolic BP standard deviation: 5.8 ± 2.1 HA vs. 5.9 ± 1.6 mmHg MDD, <i>P</i> = 0.47) nor sympathetic baroreflex sensitivity (e.g., burst incidence gain: -3.8 ± 1.3 HA vs. -3.4 ± 1.5 bursts/100 beats/mmHg MDD, <i>P</i> = 0.34) was different in MDD compared to HA. In adults with MDD, sympathetic baroreflex sensitivity was related to BPV (<i>r</i> = 0.52, <i>P</i> = 0.01). Traditional measures of beat-to-beat cardiac output and total peripheral resistance variability were likewise not different between groups (all <i>P</i> > 0.05). These data demonstrate that both beat-to-beat BPV and sympathetic baroreflex sensitivity are preserved in young unmedicated adults suffering from MDD.<b>NEW & NOTEWORTHY</b> This study investigated beat-to-beat blood pressure variability (BPV) in young unmedicated adults with major depressive disorder (MDD). The results demonstrated that both BPV and sympathetic baroreflex sensitivity were preserved in young unmedicated adults with MDD compared with healthy nondepressed young adults.