A、By reducing the blood pressure. B、By making the brain active. C、By reducing tension caused by work. D、By improving the awarene

Medical experts say most Americans do not get enough sleep and more Americans need to rest for a short period in the middle of the day. A slight sleep is suggested before continuing with other activities. A study for at least three times a week had a thirty-seven percent lower risk of dying from heart disease than those who did not nap. Study organizers said the strongest evidence was in working men. (27)The organizers said naps might improve health by reducing tension caused by work. Some European and Latin American businesses have supported the idea of napping for many years. They urge people to leave work, go home and have a nap before returning. In the United States, some companies let workers rest briefly in their offices(28)so as to reduce mistakes and accidents, and also increase the amount of work a person can do. Sleep experts say it is likely that people make more mistakes at work than at other times. They say people should not carry out important duties when Experts say this provides extra energy and can increase your effectiveness until the end of the day. But experts warn that a nap should last no more than twenty to thirty minutes. A longer nap will put the body into deep sleep. Waking up will be difficult.