Acute impact of inorganic nitrate supplementation after ischemia and during small muscle mass exercise in postmenopausal females: A pilot study

Abstract

Abstract Menopause is associated with reduced endothelial‐dependent vasodilation and increased cardiovascular disease (CVD) risk. Dietary nitrate, a non‐pharmacological approach, may increase vasodilatory capacity consequentially reducing CVD risk. We investigated macro‐ and microvascular function after acute nitrate supplementation in postmenopausal females (PMF). Vascular function was studied with flow‐mediated vasodilation (FMD) and near‐infrared post occlusive reactive hyperemia (PORH). Incremental handgrip exercise was performed to investigate blood flow and tissue oxygenation. We hypothesized acute dietary nitrate would not impact resting endothelial measures but would increase post ischemic vasodilation and incremental exercise blood flow. Late‐phase PMF (n = 12) participated in a randomized crossover design with 140 mL of nitrate‐rich (NR) beetroot juice or nitrate‐poor black currant juice. Testing included a 5‐min FMD, a 3‐min ischemic exercise FMD, and incremental exercise at 10%, 15%, and 20% maximal voluntary contraction to measure blood flow and pressure responses. A p ≤ 0.05 was considered significant. One‐way ANOVA indicated lower resting pressures, but no change to FMD, or PORH in either protocol. Two‐way repeated measures ANOVA indicated NR supplementation significantly reduced mean arterial pressure at rest and during incremental exercise at all intensities without changes to blood flow. Acute nitrate is effective for resting and exercising blood pressure management in PMF.

Keywords

• aging
• blood flow
• ischemic exercise
• near‐infrared spectroscopy
• oxygenation