英语六级阅读备考：快速阅读练习(4)

　　Passage 4

　　Set Your Bodys Time Clock

　　Our Body Operates Like a Clock

　　As the first rays of sunlight filter over the hills of Californias Silicon Valley, Charles Winget opens his eyes. It is barely 5 a.m., but Winget is raring only one-tenth of a degree in some cases but are significant. Youll probably find that your temperature will begin to rise between 3 a.m. and 6 a.m., reaching a peak sometime in the late morning or early afternoon. By evening the readings start to drop. They will steadily decline, reaching their nadir at around 2 a.m.

　　Learn to Use Your Bodys Pattern

　　Of course, individual variations make all the difference. At what hour is your body temperature oi the rise? When does it reach its highest point? Its lowest? Once you have familiarized yourself with you patterns, you can take advantage of chronobiology techniques to improve your health and productivity

　　We do our best physical work when our rhythms are at their peak. In most people, this peak lasts about four hours. Schedule your most taxing activities when your temperature is highest.

　　For mental activities, the timetable is more complicated. Precision tasks, such as mathematical work are best tackled when your temperature is on the rise. For most people, this is at 8 or 9 a.m. By contras! reading and reflection are better pursued between 2 and 4 p.m., the time when body temperature usually begins to fall.

　　Breakfast should be your largest meal of the day for effective dieting. Calories burn faster one hour after we wake up than they do in the evening. During a six-year research project known as the Army Die Study, Dr. Halberg, chronobiologist Robert Sothern and research associate Erna Halberg monitored the food intake of two groups of men and women. Both ate only one, 2000-calorie meal a day, but one group ate their meal at breakfast and the other at dinner. All the subjects lost weight eating breakfast, state; Sothern. Those who ate dinner either maintained or gained weight.

　　If foods are processed differently at different times of day, certainly caffeine, alcohol and medicines will be too. Aspirin compounds, for example, have the greatest potency in the morning, between 7 and 8. They are least effective between 6 p.m. and midnight. Caffeine has the most impact around 3 in the afternoon. Charles Walker, dean of the College of Pharmacy at Florida AM University, explains, Stimulants are most effective when you are normally active, and sedatives work best when youre naturally sedate or asleep.

　　Knowing your rhythms can also help overcome sleep problems. Consult your body-temperature chart. Your bedtime should coincide with the point at which your temperature is lowest. This is between 11 p.m. and 2 a.m. for most people.

　　Dr. Michael Thorpy of the Sleep-Wake Disorders Center at Montefiore Medical Center in New York City offers other circadian sleep tips: go to bed at the same time every night and get up at the same time every morning, even on weekends. Irregularity in sleep and waking times is the greatest cause of sleep problems, Dr. Thorpy says. The best way to recover from a bad nights sleep is simply to resume your normal cycle. Beware of sleeping pills. Most sleeping pills wont work for periods longer than two weeks, warns Dr. Thorpy. And there is real danger of drug accumulation in the blood. Visit a doctor or dentist as early in the day or as late in the evening as possible, since your highest pain threshold is between 8 p.m. and 8 a.m.

　　Winget and fellow NASA chronobiologist Charles DeRoshia also offer advice to diminish the debilitating effects of jet lag: a week or so before departure begin adjusting your daily activities so that they coincide with the time schedule of your destination. Eat a small, high-protein, low-carbohydrate meal just before your trip. Get plenty of sleep in the days before your trip. In flight, eat very little, drink lots of water and avoid alcohol and caffeinated drinks. When you arrive, walk around, talk to people, try to adapt to your environment. Before retiring, have a light meal, high in carbohydrates. Take a warm bath. Knowing your bodys patterns is no guarantee of good health. But what chronobiology reveals is the importance of regularity in all aspects of your life and of learning to act in synchronization with your bodys natural rhythms.