To Finish Strong
Coffee: Athletes who swear by the jump-start that coffee provides have reason to gloat. Endurance athletes ran on a treadmill to exhaustion in 32 minutes, but were able to last an additional 10 minutes after drinking coffee with a good dose (250 milligrams) of caffeine, according to the Journal of Applied Physiology.
The caffeine in coffee likely stimulates the nervous system, helping you ignore fatigue and recruit more muscles for intense exercise, says registered dietitian Mary Lee Chin of Nutrition Edge Communications. Greater concentration may help your performance as well, she adds. However, coffee has the potential to reduce iron absorption, and low iron stores can leave you slow and tired. If your iron levels run low, drink coffee an hour or so before meals.
Don't worry about the supposed dehydrating effects of caffeine. The Institute of Medicine of the National Academies concluded that the liquid in the beverage cancels out the mild diuretic effect of the caffeine.
Tea: Ounce for ounce, there's less caffeine in tea, so expect the performance edge to be less, too. Count on 16 ounces of black tea to contain 60 to 100 milligrams of caffeine. (An equal amount of coffee has 150 to 330 milligrams of caffeine.) In other words, you'd have to down about three cups of tea to equal one cup of joe.
However, this decreased amount of caffeine may be easier on a nervous stomach, especially on race-day morning.
To Gain the Mental Edge
Coffee: You know that the caffeine in a cup of high-grade brew will wake you up, but did you know that coffee can help boost brainpower? Chemicals in coffee may improve memory, says Dr. Peter R. Martin, director of the Institute for Coffee Studies at Vanderbilt University. A European study found that over 10 years, participants who drank three cups of coffee daily had less than half the cognitive decline of non coffee-drinkers.