Like most creatures on earth, humans come equipped with a circadian clock (生物钟), a roughly 24-hour timer that keeps our sleep patterns in line with our planet. Even though the average adult needs eight hours of sleep per night, there are “short sleepers”, who need far less, and morning people, who, research shows, often come from families of other morning people. Then there’s the rest of us, who rely on alarm clocks.
For those who dream of greeting the dawn, there is hope. Sleep experts say that with a little discipline (纪律), most people can reset their circadian clocks. But it’s not as simple as forcing yourself to go to bed earlier. You can’t make a wide-awake brain sleep.
To start, move up your wake-up time by 20 minutes a day. If you regularly rise at 8 a.m., but really want to get moving at 6 a.m., set the alarm for 7:40 on Monday. The next day, set it for 7:20 and so on. Then, after you wake up, don’t stay in bed. Hit yourself with light. In theory, you’ll gradually get sleepy about 20 minutes earlier each night, and you can make this easier by avoiding extra light exposure from computers or televisions as you near bedtime.
But resetting your circadian clock requires more commitment — in the form of unwatched football games or lost time with loved ones — than many people care to give. For some, it’s almost impossible. Very early risers and longtime night owls (夜猫子) have a hard time changing, says David F. Dinges from the University of Pennsylvania’s Perelman School of Medicine. Night-shift workers also struggle, he says, because they don’t get the environmental and social cues (暗示) that help adjust the circadian clock. The most important of these cues, called zeitgebers (German for “time givers”) is sunlight. But a zeitgeber could also be children coming home from school in the afternoon.
Besides computer screens, the biggest enemy for an aspiring (有抱负的) morning person is the weekend. Staying up later on Friday or sleeping in on Saturday sends the brain an entirely new set of information. By Monday, a 6 a.m. alarm will feel like 4 a.m. “If the old habit was practiced for a long time.” Dinges says, “the biology has a kind of memory of this.” In other words, he says, “It takes self-discipline.”
【小题1】Which of the following may have an effect on our circadian clock?| A．The noise of alarm clocks. | B．The advice of short sleepers. |
| C．The movement of the planet. | D．The habits of our family members. |
| A．Sleep as early as possible. | B．Make adaptations gradually. |
| C．Try a wide-awake brain sleep. | D．Use computers less in the daytime. |
| A．They can’t get adjusting signals. | B．They get kids disturbing their sleep. |
| C．They aren’t self-disciplined people. | D．They value time spent with loved ones. |
