정상혈압자의 Beetroot 섭취가 정적운동 시 Group IV 대사적 수용기에 미치는 영향 = Effect of Beetroot Juice on Muscle Metaboreflex in Normotensive

다국어 초록 (Multilingual Abstract)

It is reported that beetroot juice supplementation reduces blood pressure in healthy subjects at rest. It is not known that beetroot juice supplementation alters the pressor response mediated during exercise and by the muscle metaboreflex activation in normotensive. Thus, the purpose of this study was to investigate the effects of dietary nitrate derived from beetroot on muscle metaboreflex in normotensive compared with placebo. Fifteen normotensive (22.7±0.5 yrs) were recruited in this study. All subjects were assigned in a randomized, double-blind, crossover design to receive beetroot (70 mL/day, ~5.6 mmol of NO₃ -) and placebo (70 mL/day, no NO₃ -) for 15 days. The subjects completed 2 min static handgrip exercise at 50% maximal voluntary contraction followed immediately by post exercise muscle ischemia(PEMI). On day 15, the same protocol was repeated after beetroot or placebo supplementation. All subjects were continuously instrumented to measure heart rate (HR), stroke volume (SV), and obtain cardiac output (CO), mean arterial pressure (MAP), total peripheral resistance (TPR) at rest and during static exercise and PEMI. Compared with beetroot, placebo significantly decreased resting MAP (2.5±1.7 vs. -1.1±1.7 mmHg) and during exercise HR (5.4±2.2 vs. 2.6±2.6 beats/min). There were no difference in SV, CO and TPR between beetroot and placebo at rest and during static exercise and muscle metaboreflex activation. Thus, this study indicates that beetroot juice supplementation reduce MAP at rest, while no effects on muscle metaboreflex. Therefore, this study suggests that beetroot diet are regarded as healthy and associated with low incidence of cardiovascular disease in normotensive.