Tea and Endurance Sports

In a constantly changing "flavor the of the week" enviornment around nutritional performance enhancers, tea seems to withstand the test of time. Regardless of the magazine issue or dietary trend of the month, tea always works its way into the equation. For this week, I asked Randee Bloom (thanks for the guest contribution!!), an RN and tea collector/enthusiast why this is the case. Here is what she had to say:

Intense exercise or everyday normal function requires the replacement of vital nutrients and fluids. The careful selection of which dietary sources to consume and when is critical to restoration and performance. Endurance athletes are especially concerned with selecting foods and beverages that pack a punch by offering multiple benefits; such as both hydration and nutrients. Tea, the most consumed beverage in the world after water, may be a good choice.

All natural tea, including the white, green, and black varieties begins life from the same plant. It is the manufacturing process, including fermentation, which results in the different amounts of available nutrients. Because green tea is unfermented or not oxidized (the leaves are instead steamed) it does not undergo the process known to eliminate or severely reduce the naturally occurring polyphenols, including the most common and powerful, flavonoids. Compounds such as flavonoids have received considerable attention by healthcare providers and researchers as potentially offering anti-carcinogenic, anti-diabetic, anti-fungal, and even anti-viral properties. Research around the globe on animals and humans has and continues to be conducted to isolate specific benefits.

Focusing upon endurance exercise, no conclusive benefits have been reported:One research study tested green tea’s potential to improve endurance during exercise. The controlled study measured the running times to exhaustion in mice. Findings reported in the American Journal of Physiology in 2006 revealed that those animals fed green tea extract (“GTE”) had higher running times to exhaustion and higher muscle glycogen contents as compared with the exercised but not GTE-fed group. That said, no such findings have been replicated in humans. In a study published in 2010 in the International Journal for Vitamin and Nutrition Research, multiple respiratory and circulatory measurements of nine endurance-trained men were taken before, during and after exercise. Those who consumed GTE did not demonstrate performance or energy metabolism improvement. Unfortunately, the sports-science community seems to be at a mouse roadblock, for the time being anyways.

Green tea’s affect on fat oxidation:
One area of green tea’s potential benefit to all individuals, including those highly trained and seeking maximal metabolic function, is fat oxidation. A study published in the American Journal of Clinical Nutrition in 2008 found that young healthy men who consumed the equivalent of 3 ½ cups of green tea prior to their cycling measured higher fat oxidation rates, a measurement of how fat is broken down. Researchers suggested that green tea creates higher concentrations of noradrenaline, thereby stimulating fat metabolism which in turn is transported to the muscle providing fuel during exercise. This could be particularly beneficial for longer-course endurance athletes, who often race distances that deplete carbohydrate stores and require burning fat as fuel. In non-race situations, green-tea could be a helpful tool in achieving a particular body composition, by stimulating the burning of fat before during training sessions. That said, take caution (and see articles of the week) when attempting what have become known as “starvation workouts,” which while thought to increase fat-burning, may have minimal benefit and could be detrimental to training and fitness progression.

Green tea’s nutritional benefits:Rather obvious but possibly overlooked, green tea offers certain benefits as a daily fluid because of what it does not contain. Compared with common beverages of choice, green tea has relatively low levels of caffeine (certainly markedly lower than coffee, black tea, and traditional cola soft drinks). As a natural plant-based food, green tea offers a significant combination of vitamins, including more Vitamin C than black or oolong varieties. And maybe most notably, green tea contains many necessary minerals and compounds known as antioxidants. Research has demonstrated that the antioxidants in green tea are powerful enough to slow the oxidative damage to cells, possibly blocking the oxidation of LDL (bad) cholesterol and increasing HDL (good) cholesterol and improving artery function. Studies have suggested green tea drinkers reduce their risk of stroke and coronary artery disease. However, the FDA has rejected manufactures’ requests to permit labeling the beverage as “heart-healthy.” Few harmful effects have been reported following green tea consumption in otherwise healthy adults. In addition to these more general health benefits, anti-oxidants found in green tea may have a powerful effect on reducing the byproducts (e.g., crap released in the body during intense training and recovery) of oxidative stress endurance athletes place on their bodies.

In summary, as a highly available, inexpensive, and delicious beverage, green tea appears to be a safe, even smart choice, for seeking hydration. Few cautions are offered for green tea drinkers, especially noting the relatively limited amount of caffeine compared with that usually measured in black tea. However, claims that actual physiological changes can be obtained which benefit either exercise endurance or overall cardiovascular, muscular, or hematological changes have yet to be documented. It appears that the complexity of this plant and the interactions of multifaceted human biological processes challenge the study of green tea’s potential. The isolation of either a single component or a recommended dosage for optimum health or performance remains hard to find. Further studies are sure to follow, but for the time being, it seems like Green Tea is likely to help, and not do harm; something many (more expensive and highly marketed) supplements can’t necessarily say.