NITRATE SUPPLEMENTATION ALTERS CARDIOVASCULAR RESPONSES AT REST AND IN EXERCISE
Lee, J.-S., Kim, K.-A., Park, J.-S., Nho, J., Sung, S.-C., Kim, S.-H., Kim, J.-K., Stebbins, & C. L., Choi, H.-M., (2014). Effects of dietary nitrate supplementation on cardiovascular responses during dynamic exercise. Medicine & Science in Sports & Exercise, 46(5), Supplement abstract number 1327.
This study investigated the roles of cardiac output and peripheral vasoconstriction in eliciting the blood pressure response to nitrate supplementation at rest and during cycling exercise ranging from mild to heavy workloads (30%, 60%, and 80% of VO2peak) in healthy young adult Ss (N = 13). Ss supplemented their diet for 15 days with either high-rich concentrated beetroot juice (70 ml/day, 0.4 mg/day NO3-) or a nitrate-depleted beetroot juice placebo (70 ml/day, 0 mg/day NO3-). Ss were continuously instrumented to measure cardiac output and mean arterial blood pressure, and the responses to graded exercise were observed before and after beetroot juice and placebo supplementations in the same Ss.
After nitrate supplementation, plasma nitrite concentration was significantly higher at rest and during exercise compared to the placebo condition. Nitrate supplementation significantly decreased total vascular conductances and mean arterial blood pressure at rest. Those differences continued during dynamic exercise. There were no differences in cardiac output responses before and after either treatment.
Implication. Nitrate supplementation altered cardiovascular responses at rest and in dynamic exercise and as workload increased, more dilation occurred in peripheral vasculature causing less increase in mean arterial blood pressure. Nitrate supplementation may enhance vasoprotection and prevent an exaggerated blood pressure response during exercise.
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