Drinking caffeine beverages before a hard workout might give one a psychological boost, but it does nothing to increase one's endurance or help the body burn off fat more easily, according to new research.
William Winder, a BYU professor of zoology, and BYU graduate student Josephine Arogyasami believe these findings dispel a longstanding myth that caffeine functions as an ergogenic aid, or a substance that can enhance athletic performance."We found there was no - absolutely no - carbohydrate-sparing energy-savingT effect in the muscle or liver due to the caffeine," the researchers said.
"During long-term exercise, there seems to be a correlation between the time an individual runs out of muscle glycogen and the time he fatigues," said Winder. Some researchers have theorized that caffeine makes fat more available for use by muscle, causing the body to use less energy and carbohydrates during long-term exercise, Winder explained. If this were true, a person taking caffeine could exercise longer without becoming fatigued.
However, the researchers found that the rats using caffeine in their studies didn't run any longer than the rats without caffeine. Both groups used glycogen (the body's primary energy source) at the same rate, indicating that the rats on caffeine didn't burn fat any better either.
Winder and Arogyasami conducted several studies to gauge how different dosages of caffeine affected trained and untrained rats, as well as rats that had gone without food. In every situation, the caffeine failed to make a significant change in the amount of glycogen utilized.
"There may be a difference between how the rat responds and how humans would respond," Winder noted. "These studies need to be repeated in human subjects using the muscle biopsy technique so glycogen can be measured in the muscles of human subjects."
In a 1978 study on humans, other researchers concluded that caffeine increased performance by accelerating utilization of fat by the muscles, giving the body more energy resources to draw from. However, the study didn't include actual muscle glycogen measurements, and no recent studies have been able to substantiate a carbohydrate-sparing (energy-saving) effect in human subjects, Winder added.