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Impact of Acute Dietary Nitrate Supplementation on Exercise Blood Flow in Hypertension: Does Medication Status Matter?
Author(s) -
La Salle D. Taylor,
Broxterman Ryan M,
Ratchford Stephen M.,
Richardson Russell S.,
Trinity Joel D.
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.696.17
Subject(s) - blood pressure , medicine , placebo , crossover study , dietary nitrate , cardiology , diastole , heart rate , endocrinology , nitrate , chemistry , nitrite , alternative medicine , organic chemistry , pathology
Dietary nitrates are effective at lowering resting blood pressure (BP) in humans and improving skeletal muscle blood flow (BF) during exercise in animals. However, evidence of improved BP status and BF during exercise in hypertension is lacking. The purpose of this investigation was to determine if acute (3‐day) nitrate supplementation with beetroot juice (BR) lowers BP and augments BF in hypertensive individuals on and off antihypertensive medication during progressive handgrip (HG) and single‐leg knee extension (KE) exercise. In a double blind crossover study, placebo (nitrate depleted BR) and BR were administered in 14 subjects with controlled hypertension (ON‐MEDS; 53±11 yrs., 11 men, 3 women) and 14 subjects not taking antihypertensive medications (OFF‐MEDS; 49±13 yrs., 11 men, 3 women). Following either 3 days of BR or placebo supplementation, participants performed HG (15, 30, 45% of maximal voluntary contraction [MVC]) and single‐leg KE exercise (40, 60, 80% of work rate maximum [WRmax]). When OFF‐MEDs, BR significantly reduced resting diastolic BP (DBP) (BR: 84 ± 3 vs. PL: 88 ± 3 mmHg; p < 0.01) and mean arterial pressure (MAP) (BR: 101 ± 3 vs. PL: 106 ± 3 mmHg; p < 0.01), with systolic BP (SBP) trending lower (BR: 136 ± 4 vs. PL: 141 ± 5 mmHg; p = 0.067). BR did not change resting BP for the ON‐MEDS group. During HG exercise, BR supplementation only lowered SBP at 15% MVC (p < 0.05) and 30% MVC (p = 0.05) when OFF‐MEDS, with no effect on BF or vascular conductance (VC). During KE exercise, in the OFF‐MEDS group, BR significantly lowered SBP and MAP at 80% WRmax, but not at the lower intensities. When OFF‐MEDS, BR significantly increased leg BF at 40% WRmax (BR: 2667 ± 173 vs. PL: 2461 ± 193 ml/min; p = 0.04) and leg VC at 40% (BR: 24 ± 2 vs. PL: 21 ± 1 ml/min/mmHg; p < 0.01) and 60% (BR: 27 ± 2 vs. PL: 25 ± 2 ml/min/mmHg; p < 0.03) WRmax. When ON‐MEDS, BR did not alter BP, BF or VC during HG or KE exercise. These findings reveal that BR can lower BP at rest and during exercise, as well as augment the blood flow response during leg exercise in unmedicated hypertensive individuals, suggesting a potential benefit of BR to this population. Support or Funding Information This study was supported by Veteran Affairs Rehabilitation Research and Development Grant IK2RX001215 CDA2 (to J. D. Trinity) and American Heart Association Grant 14SDG1850039 (to J. D. Trinity) This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .