The Benefits of Green Tea and Exercise

By J.H. Joe, Ph.D. & H.S. Jeon, Ph.D.

Exercise and green tea are considered beneficial to our daily health. However, the combined effect of consuming green tea and exercising is not as widely known. Current research elucidates the benefits of green tea consumption in combination with exercise in both humans and mice. These benefits include improved endurance, weight loss, and resting metabolism, as well as a reduction in the oxidative stress related to exercise.

One prominent finding concerning the connection between green tea and exercise indicates that green tea enhances the body’s metabolism and adipose tissue oxidation when consumed concurrently with moderate to intense exercise over a period of a several weeks [1,2]. A human study in Japan that included moderate-intensity exercise (endurance training) over the span of 10 weeks found that the group receiving Green Tea Extract (GTE) had a decrease in whole-body fat in comparison to the group receiving a placebo. Another investigation involving overweight individuals confirms the enhancing effect of green tea on exercise [2]. 102 overweight adults were randomly assigned either GTE catechins or a placebo and made to exercise with moderate intensity over a 12-week period. The group that received the green tea supplement had a larger decrease in abdominal fat compared to the control group [2]. These studies show that, in overweight women and men, a higher concentration of green tea catechin consumption led to an increased loss in body weight and fat when combined with exercise.

According to a study on green tea and exercise, GTE usage has resulted in a 1.4 fold increase in the fat oxidation of individuals who do not perform any exercise [3]. However, it should be noted that a combination of exercise (EX) and GTE consumption led to significant fat oxidation when compared to GTE consumption alone or exercise alone [3].

Studies using mice have also shown a relationship between green tea consumption, fat usage, and endurance. Mice provided with 0.2% and 0.5% GTE were able to run 21% and 30% longer, respectively, than the mice without GTE [4]. The mice that received the extract were also shown to have experienced an ‘anti-obesity effect’ in comparison to the control mice [4]. In this particular study, it is interesting to note that caffeine was shown to have a synergistic effect with the tea catechins in promoting fat oxidation and energy usage [4]. The benefits of GTE also extend to the improvement of physical conditions. A recent study showed that in mice with a condition that simulates physical decline, the mice that were given GTE had improved endurance compared to the mice without the extract, possibly due to the increased fat utilization in place of carbohydrates [5]. Although the anatomy, physiology, and biochemical pathways in mice and humans differ, this research certainly raises interesting questions about individuals pursuing activities that require physical endurance.

Finally, green tea has properties that counteract the muscular damage and oxidative stress related to exercise. In a study that involved 35 untrained healthy men who went through strength training, the individuals who received 640 mg of GTE daily showed reduced oxidative stress after a 4 week period, as well as a trend towards reduced muscle damage when compared to the individuals who took the placebo [6]. The differences between the two groups were diminished after an 8 week period, which may be related to the adjustments that the body naturally makes to adapt to strength training [6]. Therefore, green tea may be useful for those who are beginning enter intensive physical training for the first time.

Along with the intake of green tea and copious amounts of fluids, proper exercise is important to ensure that blood is able to perfuse throughout the body and mediate an efficient exchange of nutrients and waste from the cells. Exercise not only balances weight and builds muscle, but it also facilitates blood flow in the body. Exercises like stretching help blood reach the extremities and regions of the body to which the heart has to work harder to send blood.

In conclusion, whether individuals are beginning intense physical training, exercising moderately over a long period of time, or hoping to increase their endurance, numerous trials involving humans and animals have shown the benefits of combining green tea consumption with exercise. More human trials are needed to help fully understand the role of green tea in the increase in fat oxidation and weight reduction.

References

1. Ichinose, T. et al. Effect of endurance training supplemented with green tea extract on substrate metabolism during exercise in humans. Scandinavian Journal of Medicine & Science in Sports 21, 598-605, oi:10.1111/j.1600-0838.2009.01077.x (2011).

2. Maki, K. C. et al. Green Tea Catechin Consumption Enhances Exercise-Induced Abdominal Fat Loss in Overweight and Obese Adults 1 , 2. The Journal of Nutrition, 1-7, doi:10.3945/jn. 108.098293.Materials (2009).

3. Ota, N. et al. Effects of Combination of Regular Exercise and Tea Catechins Intake on Energy Expenditure in Humans. J Health Sci 51, 233-236, doi:10.1248/jhs.51.233 (2005).

4. Murase, T., Haramizu, S., Shimotoyodome, A., Tokimitsu, I. & Hase, T. Green tea extract improves running endurance in mice by stimulating lipid utilization during exercise. American journal of physiology. Regulatory, integrative and comparative physiology 290, R1550-1556, doi:10.1152/ajpregu.00752.2005 (2006).

5. Murase, T., Haramizu, S., Ota, N. & Hase, T. Tea catechin ingestion combined with habitual exercise suppresses the aging-associated decline in physical performance in senescence-accelerated mice. American journal of physiology. Regulatory, integrative and comparative physiology 295, R281-289, doi:10.1152/ajpregu.00880.2007 (2008).

6. Jówko, E. et al. Green tea extract supplementation gives protection against exercise-induced oxidative damage in healthy men. Nutrition research (New York, N.Y.) 31, 813-821, doi:10.1016/j.nutres.2011.09.020 (2011).