Acute Consumption of New Zealand Blackcurrant Extract Has No Effect on Cycling Performance in Normobaric Hypoxia with Trained Cyclists

Introduction: New Zealand Blackcurrant Extract (NZBC) is a popular ergogenic aid used to improve endurance performance. The aim of this research was to determine the effects of a single bolus of NZBC on 10-km time trial (TT) cycling performance in normobaric hypoxia. Methods: A double-blind, crossover design study was conducted with trained cyclists. The effects of acute NZBC (900 mg) were compared with a placebo in normobaric hypoxia (NH) (FiO2 = 15.5%). Testing comprised of three laboratory-based visits for (1) familiarisation (and screening of TT performance before entry into study), (2) placebo and (3) NZBC, whereby a 10-km cycling TT was completed one hour after consumption. After completion of the TT blood lactate was assessed at four time-points in the 10 minutes following. Throughout the TT, power output (PO), rating of perceived exertion (RPE) and heart rate (HR) were recorded. Results: NZBC had no effect on TT cycling performance in NH compared to a placebo (1078.4 s [1009.4, 1147.4] and 1071.0 s [1006.4, 1137.5] respectively, p=0.31; d=-0.31). Additionally, no difference was observed for mean power output (p=0.20; d=0.39), HR (p=0.76; d=0.09) or at 1-km intervals for performance time (p=0.80), PO (p=0.77) or RPE (p=0.41). Post exercise blood lactate recovery did not differ between placebo and NZBC (p=0.42). Conclusion: Acute intake of NZBC has no effect on cycling performance or blood lactate recovery in simulated altitude.