Effects of Acute Dietary Nitrate Supplementation on Aortic Blood Pressure and Wave Reflection in Young and Older Adults

Abstract

Inorganic nitrate supplementation reduces peripheral blood pressure (BP) in several human populations. We examined whether acute nitrate supplementation decreases central aortic pressures and indices of wave reflection in young and older adults. In 13 young (25±1 yr, 10M/3F) and 12 older (64 ± 1yr, 9M/3F) normotensive adults, noninvasive aortic pressure waveforms were synthesized from high‐fidelity radial pressure waveforms via applanation tonometry before and following (60, 90, 120, 150, and 180 min) consumption of a nitrate rich beetroot juice (BR). Aortic BP and indices of aortic wave reflection (Augmentation Index; AIx and AIx normalized for heart rate; AIx@75bpm) were calculated from the generated aortic pressure waveform. Plasma nitrite concentration increased in both groups 60‐180 min following BR (P<0.001). Peripheral (Systolic: ~5mmHg; Diastolic: ~4mmHg) and aortic BP (Systolic: ~6mmHg; Diastolic: ~4mmHg) were reduced 90‐180min post BR in older (P<0.05), but not young adults. Conversely, AIx (3±3 vs ‐5±3%) and AIx@75bpm (‐6±3 vs ‐15±3%) were reduced in young adults 180 min post BR (P<0.05 for both). Whereas, AIx (28±3 vs 28±2%, P=1.0) and AIx@75bpm (21±3 vs 20±3%, P=0.99) did not change in the older adults. Our data suggest that acute dietary nitrate supplementation reduces central aortic BP in older adults, despite not altering indices of aortic wave reflection.Supported by ACSM Foundation