A new study tested the effect of regularly taking green tea extract (GTE) and found that over 10 weeks, endurance exercise performance was boosted up to 24% with 0.5% GTE supplementation, and 8% with 0.2% by-weight addition to food.
Reporting in the online edition of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology researchers at the Biological Sciences Laboratories of Kao Corp., Tochigi, Japan, said the 8-24% increase in swimming time-to-exhaustion was "accompanied by lower respiratory quotients and higher rates of fat oxidation."
The results "indicate that GTE is beneficial for improving endurance capacity and support the hypothesis that the stimulation of fatty acid utilization is a promising strategy for improving endurance capacity," according to the study entitled, "Green tea extract improves endurance capacity and increases muscle lipid oxidation in mice." Research was conducted by Takatoshi Murase, Satoshi Haramizu, Akira Shimotoyodome, Azumi Nagasawa and Ichiro Tokimitsu, working at Kao Corp., a Japanese maker of healthcare products, including green tea beverages.
Results came from the equivalent of about 4 cups of tea a day
Although it's difficult to extrapolate from mice eating GTE as a food supplement to a major leaguer or Olympic swimmer sipping green tea, the study's lead author, Takatoshi Murase said: "We estimate that an athlete weighing 75 kilograms (165 pounds) would have to drink about four cups (0.8 liter) of green tea daily to match the effect in our experiments."
"One of our important findings," Murase pointed out, "was that a single high-dose of GTE or its active ingredients didn't affect performance. So it's the long-term ingestion of G