F-46 Free Communication/Slide - Ergogenic Aids: JUNE 1, 2007 3:15 PM - 5:15 PM ROOM: 345
Previous evidence suggests that quercetin supplementation increases mitochondrial enzyme capacity in mice.
PURPOSE: To examine the effects of 3 weeks of quercetin supplementation on mitochondrial enzyme capacity and gross efficiency during 3 h of intensive cycling over 3 successive days in humans.
METHODS: Forty trained cyclists were randomized into quercetin and placebo groups and tested for VO2max (53.2±1.2, and 54.7±1.1 ml.kg-1.min-1). For 3 weeks following VO2max testing, subjects supplemented with either 1000 mg/day quercetin or placebo during normal training. At the end of the three weeks, the subjects cycled at 57% wattsmax for 3 h using their own bicycles on CompuTrainer Pro Model trainers (RacerMate, Seattle, WA) on 3 successive days. Metabolic measurements were taken every 30 minutes using the MedGraphics CPX metabolic system (St. Paul, MN) for each 3 hour ride. Muscle biopsies were obtained from the vastus lateralis immediately pre- and post-exercise on days 1 and 3. Pre and post samples from days 1 and 3 were pooled for analysis of cytochrome c by ELISA.
RESULTS: Power output remained constant for all three exercise trials, but significant decreases over time were measured for gross efficiency, cadence, glucose, RER, and muscle glycogen, and significant increases were measured for heart rate, lactate, and VO2 over time. Cytochrome c concentration was not affected by quercetin treatment. There was no quercetin treatment effect for any of the outcome measures in this study.
CONCLUSION: These data indicate that gross efficiency is reduced during an exhausting 3 hr bout of exercise. It was also found that quercetin did not significantly change mitochondrial cytochrome c concentration in these already well trained subjects.