You train hard but your endurance capacity is declining. Your muscles are aging and their capacity to burn fat is decreasing. Supplements containing catechins from green tea may offer some help, according to a 2008 animal study by the Kao Corporation.
The Japanese did experiments with a lab mouse type that ages quickly – SAMP1 – and a lab mouse type that ages at a normal rate – SAMR1. When the animals were 18 weeks old, and the SAMP1 animals already showed signs of aging, the researchers got some of the lab mice to run on a treadmill [Ex]. In the end the animals had to run for half an hour three times a week.
Some of the SAMP1 mice that had to run were given food that consisted for 0.35 percent of green tea extract [Cat]. If you convert this dose to humans you arrive at about 2-3 g green tea extract per day.
During the eight weeks that the experiment lasted, the ability of the SAMP1 mice to burn fat went down. Training slowed down the decline, but didn’t prevent the mice’s endurance capacity from declining. The combination of training and supplementation, however, kept the endurance capacity – the amount of time that the animals ran until reaching the point of exhaustion – at the same level.
The combination of green tea supplementation and training also kept the SAMP1 mice’s ability to burn oxygen up to scratch.
How exactly the interaction between green tea and training works the researchers don’t know. They did discover that green tea reduces damage caused by free radicals and keeps the genes that direct the mitochondria functioning at a young level.
“Combining catechin intake with habitual exercise is beneficial for suppressing the aging-related decline in physical performance and energy metabolism, and these effects may be attributed, at least in part, to improved mitochondrial function in skeletal muscle”, the Japanese conclude. “These results suggest that tea catechins combined with habitual exercise might be useful for preventing a decline in physical function during human aging.”