Need a pre-workout beverage to sip to help you stay hydrated? Choosing green tea may serve double-duty. Green tea is increasingly recognized as a worthy beverage to sip based on its high levels of antioxidants called catechins. Catechins are the same antioxidants found in other healthy foods including apples, berries, and chocolate. A number of studies preliminarily support the health benefits of the catechins in green tea. Now a new study shows green tea could be the ideal pre-workout sip if you’re trying to lose body fat.
Exercise and Green Tea
In a study carried at Penn State, researchers placed mice on a high-fat diet. The mice also voluntarily exercised by running. Some of the mice were given decaffeinated green tea extract before their run. Other mice exercised without green tea supplementation.
Did the mice that got green tea have an advantage? In this study they did. The mice that got the green tea supplement in the form of green tea extract showed close to a 30% reduction in body mass along with almost a 40% reduction in abdominal fat. Not to mention their metabolic profiles improved. Insulin levels dropped by up to 65% and their blood glucose levels were reduced by 17%.
Interestingly, exercise without green tea supplementation and green tea supplementation without exercise showed less significant reductions in body mass and improvements in blood sugar and insulin in this study. Exercise and green tea extract appear to have some synergy, causing greater metabolic and weight loss benefits when used together.
Does Green Tea Extract Improve Exercise Endurance?
In 2005 another study in mice showed green tea extract improved exercise endurance. One way it seems to do this is by increasing oxidation of fatty acids to fuel muscle activity. When fats are used as fuel during exercise, it helps preserve muscle glycogen. This increases exercise endurance.
What’s interesting is occasionally drinking green tea or a green tea supplement before a workout doesn’t seem to have the same benefits as drinking green tea on a regular basis. Long-term consumption of green tea as a supplement seems to offer the greatest metabolic and fat loss advantages. Based on this study, at least in mice, green tea extract enhances the ability of muscle cells to use lipids as fuel, thereby increasing exercise endurance.
Another study carried out in young men showed green tea extract increased fat oxidation in men doing a moderate-intensity cycling workout. It also improved insulin sensitivity in this study. Researchers speculate it’s the catechins in green tea that offer many of the health benefits associated with green tea.
Another way green tea extract may improve fat oxidation and exercise capacity is by its effects on catecholamines, chemicals that activate the sympathetic nervous system. Catecholamines, like norepinephrine, are released in response to exercise by adrenal glands located above the kidneys. These hormones increase fat breakdown so muscle cells can use the fatty acids for fuel. They also increase blood flow to working muscles and to the heart. At the same time, catecholamines increase heart rate and the amount of blood your heart pumps with each beat. That’s just what you want when you’re exercising hard. How does green tea extract do this? It blocks an enzyme that breaks down norepinephrine. Therefore, norepinephrine stays in your bloodstream longer.
Can You Get the Same Benefits Drinking Green Tea?
Researchers in this latest study believe the same fat-burning benefits seen in mice that exercised and supplemented with decaf green tea extract will also hold true in humans. There is a potential drawback. The amount of green tea extract they used in the study was equivalent to drinking 8 to 10 cups of green tea daily. That’s a lot of green tea to drink daily! This is not to say you can’t get some of the benefits seen in this study drinking lesser amounts, although some people may feel anxious from consuming so much caffeine. On the plus side, decaffeinated green tea may have similar benefits.
Metabolic Benefits of Green Tea
A number of studies show green tea may have metabolic benefits in people who are overweight or obese by increasing insulin sensitivity. A study published in the American Journal of Clinical Nutrition recently showed people that drank green tea had lower levels of fasting blood glucose levels and a reduction in hemoglobin A1C, a longer-term marker for blood sugar control. Therefore, green tea may have added benefits for people with metabolic syndrome and type 2 diabetes. Some research also shows it reduces biomarkers for insulin resistance – all good things when it comes to your metabolic health.
The Bottom Line?
What’s the take-home message? In addition to the other health benefits of green tea, it may help you burn more fat during exercise. Whether these results hold true in humans and whether you can get the benefits of drinking less than 8 to 10 cups of green tea a day is still uncertain. At the very least, green tea is a healthy beverage to sip in moderation and it sure beats drinking soft drinks! Coffee also offers health benefits, but skip the espresso and order a cup of green tea for a change – or substitute green tea for the black tea you currently drink – and enjoy the added health benefits.
Science Daily. “Green Tea Extract Boosts Exercise Endurance 8-24%, Utilizing Fat As Energy Source”
Nutraingredients-USA.com. “Green Tea Extracts Plus Exercise May Boost Fat Metabolism”
Am J Clin Nutr March 2008 vol. 87 no. 3 778-784
Am J Clin Nutr. 2013 Aug; 98(2):340-8.
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