Abstract
It has recently been reported that time to exhaustion during exercise after aerobic training (AT) and tea catechin (TC) intake was significantly longer than after AT alone in mice. Therefore, we examined the effects of AT and TC intake on endurance capacity and substrate utilization during prolonged exercise (EX) in humans. Fourteen male subjects (23 ± 0 yr; mean ± SE) were divided into TC intake (I; Vo2peak in ml/min/kg, 51.4 ± 1.3) and placebo groups (P; 49.1 ± 1.9). Subjects in I and P exercised on a cycle ergometer at 60% Vo2peak for 1 h/day, 3 days/wk, and daily ingested a test beverage containing 584 or 0 mg of TC for 10 wk, respectively. Before and after AT, respiratory gas exchange was measured during 90-min EX at pretraining ∼55% Vo2peak. After AT, Vo2peak increased by 16.0% in I and 15.7% in P (P < 0.05), and ventilation threshold (VT) by 24.1% in I and 26.0% in P (P < 0.05), with no significant differences in the changes between both groups. Whole body fat oxidation rate, calculated by indirect calorimetry, increased by ∼18.0% in I throughout 90-min EX (P < 0.05), whereas by ∼13.6% in P only during the first 45 min of EX (P < 0.05). Thus TC intake did not affect the increases in Vo2peak and VT, but enhanced fat utilization during prolonged EX, possibly contributing to the improvement in exercise performance by sparing muscle glycogen utilization. [J Physiol Sci. 2007;57 Suppl:S187]
