Author(s): GILES, L., BRANDENBURG, J.P., Institution: UNIVERSITY OF THE FRASER VALLEY, Country: CANADA, Abstract-ID: 858

INTRODUCTION:
Exercise with an eccentric component (e.g., running with a downhill portion) results in oxidative stress and inflammation, as well as transient increases in arterial stiffness, muscle damage, and dysfunction. During prolonged strenuous exercise, supplementation with foods rich in antioxidants, such as blueberries, could augment antioxidant and anti-inflammatory defences, thus reducing any adverse physiological effects, countering fatigue, and enhancing performance. Therefore, the purpose of this study was to assess if supplementation with freeze dried blueberry powder influences symptoms and the cardiovascular, muscular, and performance effects of a 22.2-km trail run.
METHODS:
10 Healthy runners (4F 6M, 176.0 ± 8.8 cm, 71.1 ± 12.4 kg, 38.4 ± 8.9 y; mean ± SD) performed two 22.2-km trail runs as fast as possible (3 x 7.4 km loops, 280 m elevation per loop) following 7-days of supplementation with freeze dried blueberry powder or placebo (order randomized, double blind). Prior to, immediately following, and 24 h following the run, participant symptoms, pulse wave analysis (PWA), pulse wave velocity (PWV), muscle function (reactive strength index [RSI] and jump height via a drop jump), and muscle soreness were measured. Exercise heart rate (HR) was measured during the run while blood lactate was assessed before and after the run. Time to complete the trail run, and mean and maximum HR during the run, were analysed using a paired t-test. Pre and post blood lactate were analyzed using a 2 (supplement vs. placebo) X 2 (time: pre-post) repeated measured ANOVA. Loop times were analyzed using a 2 (supplement vs. placebo) X 3 (loop 1-2-3) repeated measured ANOVA. Symptoms, PWV, PWA, RSI, jump height, and muscle soreness were analyzed using a 2 (supplement vs. placebo) X 3 (time: pre-post-24h) repeated measured ANOVA.
RESULTS:
Trail run time was significantly faster following blueberry powder supplementation (p=0.003; 9425.22 ± 1311.29 vs. 9870.11±1521.30 s). There was a main effect of supplement on average loop time, with loop time being significantly faster following blueberry powder supplementation (p=0.005; 3141.63 ± 439.75 VS. 3291.15 ± 504.70 s). There was a main effect of supplement for HR measured during PWA (p=0.026) and feelings of tiredness measured prior to or following the run (p= 0.007). Both HR (56.37 ± 9.42 vs. 58.70 ± 10.08 BPM) and tiredness (1.37 ± 1.11 vs. 2.07 ± 1.16 on a 7-point scale) were significantly lower following blueberry powder supplementation. There were no significant differences in mean and maximum run HR, or blood lactate prior to and following the run. There were no other main or interaction effects for RSI, jump height, muscle soreness, PWV, or other measures of PWA or symptoms.
CONCLUSION:
These results indicate that supplementation with freeze dried blueberry powder improves prolonged trail running performance and feelings of tiredness.