Impact of Acute Dietary Nitrate Supplementation during Exercise in Hypertensive Women

Introduction the aim of the current investigation was to examine if dietary nitrate supplementation would improve vascular control in hypertensive post-menopausal women (PMW). We tested the hypotheses that acute dietary nitrate supplementation would 1) significantly decrease arterial blood pressure (BP) at rest and during exercise; 2) increase limb blood flow during steady-state exercise; and 3) improve functional sympatholysis during steady-state (SS) exercise. Methods ten hypertensive PMW underwent a randomized, double-blind placebo-controlled trial with a nitrate-rich (NR) or nitrate poor (NP) supplement. Beat-by-beat BP and heart rate were recorded throughout the trial on the non-exercising limb. Forearm blood flow (FBF) was measured via ultrasonography on the brachial artery of the exercising limb. All patients performed a resting cold pressor test (CPT) (2 min) and then 7 min of submaximal hand-grip exercise with a CPT applied during min 5-7. Results SS systolic (NR: 170±7; NP: 171±37 mmHg), diastolic (NR: 89±2; NP: 92±2 mmHg) and mean arterial (NR: 121±4; NP: 123±2 mmHg) pressures were not different between NP and NR treatment conditions (p>0.05). During SS exercise, FBF (NR:189±8; NP: 218±8 ml min-1; P=0.03) in the NR treatment was significantly lower compared to NP. When the CPT was applied during min 6-7 of exercise forearm vascular conductance was reduced by 15% in the NR condition, but only 7% in the NR condition. Conclusion in summary, an acute NR supplement improved functional sympatholysis by ~50% versus a NP placebo condition. Improvements in functional sympatholysis may have important implications regarding exercise tolerance in hypertensive PMW. Address for correspondence: Carl J. Ade, Ph.D., Department of Kinesiology, Kansas State University, 1A Natatorium, Manhattan, KS, 66506, Tel: 785.532.6765. E-mail: cade@ksu.edu The authors disclose funding for the current study was provided by Kansas State University start-up funds for Dr. Carl Ade. The authors declare that the results of the investigation are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation and the results of the present investigation do not constitute endorsement by ACSM. Accepted for Publication: 21 November 2018. © 2018 American College of Sports Medicine

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