J.P. Brandenburg1, M. Gaetz1, L.V. Giles2

1University of the Fraser Valley, Chilliwack, BC, 2Douglas College, New Westminster, BC

Blueberries are rich in a class of polyphenol called anthocyanins. As the antioxidant properties of anthocyanins seem to offset mechanisms of fatigue, blueberry supplementation may aid performance. PURPOSE: To examine the effects of two doses of blueberry supplementation on running performance, physiological responses, and recovery. METHODS: Fourteen recreational runners (31.3 ± 10.3 years; 174.3 ± 11.1 cm; 72.1 ± 13.1 kg; 51.1 ± 6.2 mL·kg−1·min−1) supplemented with 3 different protocols: 4 days of blueberries (4DAY), 4 days of placebo (PLA), and 2 days of placebo followed by 2 days of blueberries (2DAY). Following supplementation, participants completed an 8 km time trial on a non-motorized treadmill. Heart rate (HR) and ratings of perceived exertion (RPE) were monitored during the time trial. Blood lactate, vertical jump, and reactive strength index (RSI) were assessed before and after the time trial. RESULTS: No significant differences were observed in time to complete the 8 km run (PLA: 3010±459s; 2DAY: 3014±488s; 4DAY: 3011±423s), mean HR during the time trial (PLA: 171±14; 2DAY: 172±14; 4DAY: 170±12), and mean RPE (PLA: 15.4±1; 2DAY: 15.5±1; 4DAY: 15.3±1). A significant interaction effect (p=0.027) was observed for blood lactate responses; post hoc analysis revealed that 5 minutes post-time trial lactate was significantly less in 4DAY (5.4±2.0 mmol*l-1) than PLA (6.6±2.5 mmol*l-1; p=0.038) and 2DAY (7.4±3.4 mmol*l-1; p=0.034). Blood lactate recovery within 30 minutes of time trial completion was similar between conditions. Post time trial decreases in vertical jump height, though significant (p=0.038). CONCLUSION: Two days of blueberry supplementation had no impact on time trial performance, physiological stress, or recovery. Four days of blueberry supplementation did not alter performance, but blunted the blood lactate increase to running, perhaps reflecting an alteration in lactate production and/or clearance; and minimized the post-time trial impairment in RSI, perhaps suggesting a protection against acute muscular impairment.

Supported by US Highbush Blueberry Council.

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