A、Introducing readers to unfamiliar situations. B、Reminding readers of the truth. C、Informing people new scientific development.

Recently, (35) researchers in England discovered that simply rinsing your mouth with a sports drink may fight fatigue.  In the experiment, which was published online in February in the Journal of Physiology. eight well-trained cyclists completed a strenuous, all-out time trial on stationary bicycles in a lab.  The riders were hooked up to machines that measured their heart rate and power output.  Throughout the ride, the cyclists were with various liquids in their mouths but did not swallow. (33) Some of the drinks contained carbohydrates, the primary fuel used during exercise. (33) The other drinks were just flavored, sugar-free water. By the end of the time trials, (33) the cyclists who had rinsed with the carbohydrate drinks—and spit them out—finished significantly faster than the water group. Their heart rates and power output were also higher. But when rating the difficulty of the ride, on a numerical scale, their feelings about the effort involved matched those for the water group. In a separate portion of the experiment, (34) the scientists found that areas within the brain that are associated with reward, motivation and emotion were activated when subjects were with a carbohydrate drink.  It seems that the brains of the riders getting the carbohydrate-containing drinks sensed that the riders were about to get more calories, which appears to have allowed their muscles to work harder even though they never swallowed the liquid.