Acute apnea increases central blood pressure and arterial wave reflection in young healthy adults

BACKGROUND: Apnea causes sympathetically mediated vasoconstriction and an increase in blood pressure (BP). Reoccurring bouts of apnea (i.e. sleep apnea) are associated with increased cardiovascular risk such as left ventricular structure and function abnormalities. However, it is unclear if acute apnea negatively impacts arterial wave reflections and aortic BP, which often precedes deleterious left ventricular changes. PURPOSE: We aimed to assess if sympatho-excitation via voluntary apnea impacted pulsatile load and wave reflection. We hypothesized that there would be increases in pulsatile load and wave reflection. METHODS: Twenty-eight apparently healthy adults (n = 14 females, 27 ± 5 years, 24.2 ± 2.7kg/m2) participated in this study. Each participant was equipped with a continuous finger BP cuff to capture beat-to-beat BP and an applanation tonometry to record radial artery pressure waveforms. Participants were instructed to hold their breath until volitional breakpoint following inhalation or exhalation, within a normal tidal volume, in a randomized cross over design with a 15 min washout period between each condition. We compared central blood pressure and indices of pulsatile arterial load and wave reflection at baseline with the last 10 seconds of each breath hold (BH) with paired t-tests. RESULTS: Compared to respective baselines, central systolic BP increased during exhalation BH (100.0 ± 7.4, 110.0 ± 13.7mmHg, p < 0.001) and inhalation BH (100.1 ± 9.6, 110.6 ± 11.5mmHg, p < 0.001). Compared to respective baselines central diastolic BP also increased during exhalation BH and inhalation BH (both p < 0.001). Compared to respective baselines, augmentation index increased during exhalation BH (12 ± 13 vs. 21 ± 12 %, P < 0.001) and inhalation BH (15 ± 12 and 24 ± 11 %, P < 0.001). Compared to respective baselines, reflection magnitude increased during exhalation BH (40 ± 8 and 45 ± 9 %, p < 0.001) and inhalation BH (41 ± 8 and 48 ± 8 %, p < 0.001). Compared to respective baselines, wasted pressure effort relative to the time integral of the product of time-resolved flow and characteristic impedance (WPE:QZc) increased during exhalation BH (40 ± 16 and 50 ± 19 % (P < 0.01) and inhalation BH (45 ± 19 and 55 ± 19 %, P < 0.01) WPE:QZc. There were no statistical differences between change in hemodynamics between inhalation and exhalation (all p > 0.05). CONCLUSION: Sympatho-excitation via maximal voluntary breath holds following exhalation and inhalation significantly increased central BP and arterial wave reflection. 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.