That's right: Researchers from Granada University in Spain published results from a recent study that tested the hydration powers of water versus beer, and a results were surprising.

After students performed strenuous exercise until exhaustion in 104 degree Fahrenheit temperatures, one group was given two pints of beer while the other group drank the same amount of water. Both groups were then allowed to drink as much water as they wanted and their hydration levels were tested soon after. The tests revealed a slightly better measurement in the beer drinkers than those who drank water. Surprising? According to common principles of nutrition, this finding may be scientifically grounded. However, the same science may keep you from downing a six pack after your next run.

During exercise, the average person may lose close to a liter of water in sweat, through which a person can lose significant amounts of electrolytes like sodium and potassium. Depending on the intensity of the exercise, one can also deplete significant amounts of the fuels used to power physical activity. While activities of lower intensity tend to utilize fat as a primary fuel source, more demanding activities rely on glycogen, a storage form of glucose, which is found primarily in muscles. The degree to which muscle glycogen can be re-synthesized after exercise is a key component in recovering from strenuous aerobic exercise and is a marker for how well people can perform during their next workout.

Depending on a beverage's carbohydrate content and how quickly after exercise it is consumed, certain drinks will replenish glycogen stores better than others. Sports drinks consisting mainly of water and a glucose-fructose syrup will always be the best choice for post-exercise recovery. Drinking products such as Gatorade and Powerade are especially good hydrators because they contain key electrolytes such as sodium, which aid in fluid retention and encourages drinking. Pure water, on the other hand, may succeed in quenching thirst and replacing fluids to some degree, but beverages laden with carbohydrates will always have an advantage over water when it comes to replenishing glycogen. So how does beer, which contains about 10 grams of carbohydrate per 12 ounces, compare to these stereotypical thirst quenchers in its ability to hydrate and replenish glycogen?

A review paper published by the School of Sport and Exercise Sciences at Loughborough University, UK, states that synthesis of glycogen in both the muscles and the liver of animals is impaired, even when relatively low levels of alcohol are consumed. Alcohol slows both digestion and absorption of glucose, the key ingredient used to make glycogen, so if alcohol is used to replace a high carbohydrate meal after exercise, beer will simply not make the cut. While a pint of beer might be a better means of hydration than one glass of water, water does not show the same potential to slow the synthesis of glycogen, nor does it show the same potential to dehydrate if consumed in larger amounts.

"Low alcohol beverages aren't too bad for hydration, especially if you begin a bit dehydrated, but higher alcohol content beverages are detrimental," said Janet Rankin, a Virginia Tech professor of sports nutrition.  

Alcohol has a significant diuretic effect on the body, and beverages like beer, which contain around 4 percent alcohol per volume, tend to delay the recovery process by promoting urine loss. This effect is amplified with each beer you drink and is even greater when you drink liquor or wine. While one pint of beer may not produce significant urine loss, this is still an interesting piece of information for those who like to go out drinking after a Friday afternoon workout.

Despite Granada's findings, it is hard to recommend a cold beer to someone as a means of proper recovery after a workout, and it's just not a smart choice when the goal is optimal recovery. Alcohol has been shown to inhibit optimal glycogen synthesis after exercise and also to impair hydration when consumed in higher amounts, but the small amount of beer suggested in Granada's study would probably not be enough to elicit these effects. However, if your goal is to come back strong during your next workout, the best choice will always be a sports drink for post-exercise recovery.