Green Tea and Exercise: Can It Improve Performance?
Where green tea seems to have benefits is for exercise endurance. In one study, researchers found that mice fed a green tea extract over a 10-weeks period were able to swim up to 24% longer before exhaustion set in. To control for the effects of caffeine, they used a green tea extract that was low in caffeine. Why would green tea catechins have this benefit? The same catechins that give green tea its cell-protective properties appear to boost the use of fat as fuel during exercise, thereby preserving glycogen stores. That can help you exercise longer.
Does the same apply to humans? In another study involving human cyclists, researchers found a similar effect of green tea on endurance performance. By measuring gas exchange, they showed the cyclists who took a green tea extract for ten weeks used more fat as opposed to carbohydrates as fuel during endurance exercise. How does this improve endurance? When your body taps into fat stores, you hold onto your most valued energy supply – glycogen. This study adds to a growing body of evidence that the catechins in green tea modestly increase exercise endurance by causing your cells to use more fat as fuel.
How Much Do You Need to Get the Benefits?
Even though most studies looking at green tea and exercise use a green tea extract for standardization, researchers point out that drinking four cups of green tea a day should be enough to get the benefits. They also emphasize that drinking green tea one time before a workout won’t have the same effect as drinking it on a regular basis. To get this kind of benefit, it needs to be a daily habit.
Can Green Tea and Exercise Help You Lose Weight Too?
Some people sip green tea in hopes of boosting their metabolism so they can lose weight. Is it likely to help? Research suggests that green tea catechins have a modest metabolism-boosting effect. In one study, they boosted fat metabolism by around 4%. This certainly isn’t enough to cause profound weight loss, but the results may be quite gratifying if you replace all the beverages with calories you drink with unsweetened green tea. Green tea isn’t a “magic bullet” for weight loss but it can be part of a healthy weight loss program when combined with an exercise program.
A Potential Drawback of Drinking Green Tea Before a Workout?
One study showed that the catechin-antioxidants in green tea protect against free radical damage to muscles when you sip green tea or take a supplement. That sounds like a good thing until you consider recent studies show some degree of oxidative stress might be a good thing because it causes your body to “adapt” to oxidative stress. This adaptation may be important for getting the full benefits of a workout including increased insulin sensitivity.
One study showed that people who took antioxidant vitamin supplements, vitamin C and E, didn’t experience an increase in insulin sensitivity in response to exercise. So whether or not it’s a good idea to take in a lot of antioxidants before a workout is a good idea isn’t clear.
The Bottom Line?
Green tea catechins may improve exercise endurance by increasing your body’s ability to use fat as an energy source during exercise. It also may modestly boost your metabolism, although by itself it’s unlikely to have a major impact on weight loss. Since your body appears to need some oxidative stress to fully adapt, avoid taking antioxidants in supplemental form and loading up on antioxidants before a workout.
References:
Mayo Clinic. “Tea: Enjoy a Cup for Health and Pleasure”
Scand J Med Sci Sports. 2011 Aug;21(4):598-605.
Eurekalert.org. “Green Tea Extract Boosts Exercise Endurance 8-24%, Utilizing Fat as Energy Source”
Am. J. Clin. Nutr. 70 (6): 1040–5.
Nutr Res. 2011 Nov;31(11):813-21. doi: 10.1016/j.nutres.2011.09.020.
Proceedings of the National Academy of Sciences, May 12, 2009.
Sports Med. 2011 Dec 1;41(12):1043-69.
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Right nutrition plays crucial role. When you are training hard, your body needs lots of energy in order not to be exhausted. I was recommended to take dietary supplements developed for the U.S. Army – Military Grade Nutritionals. I must say, the result was awesome! I felt still energized even after highly intensive workouts, my reps went sharply up, and now I am in the best shape of my life. Will definitely go on like this.