The polyphenol compound anthocyanin present in blackcurrant juice (BC) has been found to elicit positive biological action in terms of cardiovascular and metabolic functions. Supplementation of BC may also enhance aerobic exercise performance. With seven days intake of New Zealand blackcurrant powder, a shift of the lactate curve was observed with 4 mmol /lof lactate obtained at higher power output. Acute effects of BC intake on responses during exercise are not fully known. Therefore, the actions of an acute intake of anthocyanins in BC may affect exercise performance benefits in relation to blood lactate, power output, heart rate and time in a standard exercise ramp test. This study set out to ascertain if acute supplementation of a high dose of BC affects responses during an incremental cycling protocol in healthy trained cyclists. The primary purpose of this study was to examine whether a single dose of BC ingested prior to the endurance ramp protocol may affect parameters at a blood lactate (BLa) value of 4mmol/l. The design was a randomized controlled trial using blinding. The study sample was 14 male endurance athlete: height (175±7 cm), weight (71.3 ± 8.9 kg), age (36±6 y). Each subject was blinded and received either a BC or placebo (PLa) juice in 500ml liquid with 300ml of BC containing 105mg of anthocyanin or coloured water 2h prior to testing. The endurance ramp protocol test to 4mmol/l BLa was performed on a Watt bike ergometer starting at 125W with 3 min stages of 25W increments to reach 4mmol/l BLa. Power, time and heart rate were measured at each 3 min interval; all metrics were recorded, compared using t- test and analysed on Graphpad Prism statistical software (P<0.05). There was difference after a high dose of BC in power (BC: 227±5 W (n 6), PLa: 222±5 W (n=6), P=0.54), time (BC: 15.3±0.6 min (n=6), PLa: 14.2±0.9 min(n=6), P=0.37) and heart rate (BC: 155±2beats/min (n=6), PLa: 160±3beats/min (n=6), P=0.29) to reach a blood lactate value of 4 mmol/l. A single dose of BC had no effect on power, time or heart rate in an endurance ramp protocol test to reach a blood lactate value of 4mmol/l. Future studies may examine how many days intake of blackcurrant are required to observe changes in physiological and performance responses during exercise testing in trained endurance athletes.
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