Sports drinks improve endurance...

Sports drinks containing protein appeared to improve endurance among cyclists compared to those drinking a carbohydrate-only beverage in a new study.

It is not clear whether the effects were merely a result of additional calories from the protein or because of specific protein-mediated mechanisms.

However the findings give some early indications of potential benefits of adding proteins to sports drinks.

The study of 15 male cyclists compared Accelerade, a sports drink containing carbohydrates and whey protein marketed by US-based PacificHealth Laboratories, with a carbohydrate-only drink, similar to many products on the market today.

The researchers based at James Madison University in Virginia, US asked cyclists to pedal to the point of exhaustion while replenishing with either the protein-added or carb-only drink every 15 minutes. The athletes performed a second, more demanding ride the next day. One to two weeks later, they went through the process again, this time with the other drink.

Writing in the journal Medicine in Science and Sports Exercise, the researchers report that the men lasted 29 per cent longer during the first test and 40 per cent longer during the second test when they drank the protein-containing drink.

There were also signs of less exercise-induced muscle damage, according to the researchers. After the exercise tests, the cyclists' blood levels of creatine phosphokinase — an enzyme released from muscles under stress — were lower when they consumed protein during the workout.

Reference
Saunders MJ, Kane MD, Todd MK. (2004). Effects of a carbohydrate-protein beverage on cycling endurance and muscle damage. Medicine and Science in Sports and Exercise, 36, 1233-1238