title: Epigallocatechin-3-gallate increases maximal oxygen uptake in adult humans.
abstract: Epigallocatechin-3-gallate (EGCG), a component of green tea, increases endurance performance in animals and promotes fat oxidation during cycle ergometer exercise in adult humans.
  
  
  OBJECTIVE
  We have investigated the hypothesis that short-term consumption of EGCG delays the onset of the ventilatory threshold (VT) and increases maximal oxygen uptake (VO2max).
  
  
  METHODS
  In this randomized, repeated-measures, double-blind study, 19 healthy adults (11 males and 8 females, age = 26 ± 2 yr (mean ± SE)) received seven placebo or seven EGCG (135-mg) pills. Forty-eight hours before data collection, participants began consuming three pills per day; the last pill was taken 2 h before exercise testing. VT and VO2max were determined from breath-by-breath indirect calorimetry data collected during continuous incremental stationary cycle ergometer exercise (20-35 W·min(-1)), from rest until volitional fatigue. Each condition/exercise test was separated by a minimum of 14 d.
  
  
  RESULTS
  Compared with placebo, short-term EGCG consumption increased VO2max (3.123 ± 0.187 vs 3.259 ± 0.196 L·min(-1), P = 0.04). Maximal work rate (301 ± 15 vs 301 ± 16 W, P = 0.98), maximal RER (1.21 ± 0.01 vs 1.22 ± 0.02, P = 0.27), and maximal HR were unaffected (180 ± 3 vs 180 ± 3 beats·min(-1), P = 0.87). In a subset of subjects (n = 11), maximal cardiac output (determined via open-circuit acetylene breathing) was also unaffected by EGCG (29.6 ± 2.2 vs 30.2 ± 1.4 L·min(-1), P = 0.70). Contrary to our hypothesis, EGCG decreased VO2 at VT (1.57 ± 0.11 vs 1.48 ± 0.10 L·min(-1)), but this change was not significant (P = 0.06).
  
  
  CONCLUSIONS
  Short-term consumption of EGCG increased VO2max without affecting maximal cardiac output, suggesting that EGCG may increase arterial-venous oxygen difference.
authors: Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523-1582, USA.
authors: Jennifer C
authors: JC
authors: Richards
authors: Mark C
authors: MC
authors: Lonac
authors: Tyler K
authors: TK
authors: Johnson
authors: Melani M
authors: MM
authors: Schweder
authors: Christopher
authors: C
authors: Bell
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008451:Maximal Voluntary Ventilation / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects*; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology; D055815:Young Adult
chemical_list: D000975:Antioxidants; D002392:Catechin; C045651:epigallocatechin gallate