Blackcurrant Alters Physiological Responses and Femoral Artery Diameter during Sustained Isometric Contraction.

Matthew David Cook,Stephen David Myers,Mandy Lucinda Gault,Mark Elisabeth Theodorus Willems

doi:10.3390/nu9060556

Matthew David Cook, Stephen David Myers + Show 2 more

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https://doi.org/10.3390/nu9060556

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Abstract

Blackcurrant is rich in anthocyanins that may affect exercise-induced physiological responses. We examined tissue oxygen saturation, muscle activity, cardiovascular responses and femoral artery diameter during a submaximal sustained isometric contraction. In a randomised, double-blind, crossover design, healthy men (n = 13, age: 25 ± 4 years, BMI: 25 ± 3 kg·m−2, mean ± SD) ingested New Zealand blackcurrant (NZBC) extract (600 mg∙day−1 CurraNZ™) or placebo (PL) for 7-days separated by 14-days washout. Participants produced isometric maximal voluntary contractions (iMVC) and a 120-s 30%iMVC of the quadriceps with electromyography (EMG), near-infrared spectroscopy, hemodynamic and ultrasound recordings. There was no effect of NZBC extract on iMVC (NZBC: 654 ± 73, PL: 650 ± 78 N). During the 30%iMVC with NZBC extract, total peripheral resistance, systolic, diastolic, and mean arterial pressure were lower with increased cardiac output and stroke volume. With NZBC extract, EMG root mean square of the vastus medialis and muscle oxygen saturation were lower with higher total haemoglobin. During the 30%iMVC, femoral artery diameter was increased with NZBC extract at 30 (6.9%), 60 (8.2%), 90 (7.7%) and 120 s (6.0%). Intake of NZBC extract for 7-days altered cardiovascular responses, muscle oxygen saturation, muscle activity and femoral artery diameter during a 120-s 30%iMVC of the quadriceps. The present study provides insight into the potential mechanisms for enhanced exercise performance with intake of blackcurrant.

Highlights

Blackcurrant contains a high and specific content of anthocyanins [1], considered to be the essential bioactive berry compounds
There was no effect of New Zealand blackcurrant (NZBC) on maximal isometric voluntary contraction force (NZBC: 654 ± 73, PL: 650 ± 78 N, p = 0.732) or average force during the sustained isometric contraction for 120 s
Before the sustained isometric contraction, there were no differences in systolic blood pressure (NZBC: 126 ± 11, PL: 126 ± 11 mmHg, p = 0.901), diastolic blood pressure (NZBC: 75 ± 10, PL: 72 ± 9 mmHg, p = 0.319), mean arterial pressure (NZBC: 91 ± 10, PL: 89 ± 10 mmHg, p = 0.553), heart rate (NZBC: 75 ± 8, PL: 71 ± 10 beats·min−1, p = 0.204) and ejection time (NZBC: 0.27 ± 0.02, PL: 0.27 ± 0.01 s, p = 0.330)

Summary

Introduction

Blackcurrant contains a high and specific content of anthocyanins [1], considered to be the essential bioactive berry compounds. Matsumoto et al [6] observed with blackcurrant intake an increase in forearm blood flow at rest following arterial occlusion, and a higher change in total haemoglobin in the trapezius muscle during a maximal voluntary contraction (MVC) after 30 min of typing, measured by infrared spectroscopy (NIRS). Such observations may be mediated by the blackcurrant anthocyanins (or metabolites) influencing vasodilation and relaxation [7], by increasing production of nitric oxide. Other in vivo studies observed anthocyanins to vasodilate blood

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