Acute dietary nitrate supplementation improved functional sympatholysis by ~50% versus placebo, despite lowering forearm blood flow during steady-state exercise (189 vs 218 mL/min; P=0.03).
RCT (n=10)
Double-blind
Randomized
Does acute dietary nitrate supplementation improve vascular control, blood pressure, and functional sympatholysis during exercise in hypertensive postmenopausal women?
Acute dietary nitrate supplementation improves functional sympatholysis during exercise in hypertensive postmenopausal women, which may have implications for exercise tolerance despite not acutely lowering blood pressure.
Absolute Event Rate: 189% vs 218%
p-value: p=0.03
INTRODUCTION: the aim of the current investigation was to examine if dietary nitrate supplementation would improve vascular control in hypertensive postmenopausal 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 (SS) exercise, and 3) improve functional sympatholysis during 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 nonexercising limb. Forearm blood flow 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 handgrip exercise with a CPT applied during minutes 5-7. RESULTS: SS systolic (NR, 170 ± 7; NP, 171 ± 37 mm Hg), diastolic (NR, 89 ± 2; NP, 92 ± 2 mm Hg), and mean arterial (NR, 121 ± 4; NP, 123 ± 2 mm Hg) pressures were not different between NP and NR treatment conditions (P > 0.05). During SS exercise, forearm blood flow (NR, 189 ± 8; NP, 218 ± 8 mL·min; P = 0.03) in the NR treatment was significantly lower compared with NP. When the CPT was applied during minutes 6-7 of exercise, forearm vascular conductance was reduced by 15% in the NR condition, but only 7% in the NR condition. CONCLUSIONS: In summary, an acute NR supplement improved functional sympatholysis by ~50% versus an NP placebo condition. Improvements in functional sympatholysis may have important implications regarding exercise tolerance in hypertensive PMW.
Caldwell et al. (Fri,) conducted a rct in Hypertension (n=10). Dietary nitrate supplementation (nitrate-rich supplement) vs. Nitrate-poor supplement (placebo) was evaluated on Forearm blood flow during steady-state exercise (mL/min) (p=0.03). Acute dietary nitrate supplementation improved functional sympatholysis by ~50% versus placebo, despite lowering forearm blood flow during steady-state exercise (189 vs 218 mL/min; P=0.03).