Charles Winget opens his eyes. It is barely 5 a.m., but Winget is raring to go. Meanwhile, his wife pulls up the covers and buries her face under the pillow. “For the past fifteen years,” says Winget, “we?ve hardly ever gotten up together.”
2. The Wingets? situation is not uncommon. Our bodies operate with the complexity of clocks, and like clocks, we all run at slightly different speeds. Winget is a morning person. His wife is not at her best until after nightfall.
3. Behavioral scientists long attributed such differences to personal eccentricities or early conditioning. This thinking was challenged in the late 1950s by a theory labeled chronobiology by physician-biologist Franz Halberg. In a Harvard University laboratory, Dr. Halberg found that certain blood cells varied predictably in number, depending on the time of day they were drawn from the body. The cell count was higher at a given time of day and lower 12 hours later. He also discovered that the same patterns could be detected in heart and metabolic rates and body temperature. 4. Halberg?s explanation: instead of performing at a steady, unchanging rate, our systems function on an approximately 25-hour cycle. Sometimes we are accelerating, sometimes slowing down. We achieve peak efficiency for only a limited time each day. Halberg called these regular patterns “circadian rhythms.”
5. Much of the leading work in chronobiology is sponsored today by the National Aeronautics and Space Administration. Charles Winget, a NASA research physiologist and authority on circadian rhythms, says that circadian principles have been applied to astronauts? work schedules on most of the space-shuttle flights.
6. The space-age research has many useful applications here on earth. Chronobiologists can tell you when to eat and still lose weight, what time of day you?re best equipped to handle the toughest challenges, when to go to the dentist with your highest threshold of pain and when to exercise for maximum effect. “It?s a biological law of human efficiency: to achieve your best with the least effort, you have to coordinate the demands of your activities with your biological capacities,” Winget says.
7. Circadian patterns can be made to work for you. But you must first learn how to recognize them. Winget and his associates have developed the following approach to help you figure out your body?s patterns.
8. Take your temperature one hour after getting up in the morning and then again at four-hour intervals throughout the day. Schedule your last reading as close to bedtime as possible. You should have five readings by the end of the day.
9. Now add your first, third and fifth readings and record this total. Then add your second and fourth readings and subtract this figure from the first total. That number will be an estimate of your body temperature in the middle of the night. Consider it your sixth reading.
10. Now plot all six readings on graph paper. The variations may seem extremely small — only one-tenth of a degree in some cases — but they are significant. You?ll 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 lowest points at around 2 a.m.
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11. Of course, individual variations make all the difference. At what hour is your body temperature on the rise? When does it reach its highest point? Its lowest? Once you have familiarized yourself with your patterns, you can take advantage of chronobiology techniques to improve your health and productivity.
12. 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 demanding activities when your temperature is highest.
13. 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 contrast, reading and reflection are better pursued between 2 and 4 p.m., the time when body temperature usually begins to fall.
14. 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 Diet 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,” states Sothern. “Those who ate dinner either maintained or gained weight.”
15. If foods are processed differently at different times of the day, certainly caffeine, alcohol and medicines will be too. Aspirin compounds, for example, produce the greatest effect in the morning, between 7 and 8. (So does alcohol.) 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 A & M University, explains, “Stimulants are most effective when you are normally active, and sedatives work best when you?re naturally sedate or asleep.”
16. Knowing your rhythms can also help you 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.
17. 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 night?s sleep is simply to resume your normal cycle. Beware of sleeping pills. “Most sleeping pills won?t work for periods longer than two weeks,” warns Dr. Thorpy. And there is real danger of drug accumulation in the blood.
18. Knowing your body?s 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 body?s natural rhythms.
▇ 课文参考译文
设定你的生物钟为你效劳
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芭芭拉·罗斯
1 当第一缕曙光映照在加利福尼亚硅谷小山上空，查尔斯·温格特就睁开了双眼。刚早晨五点钟，温格特就急不可待地要出门。此时，他的妻子把被子往上一拉，把脸埋在枕头下。温格特说，“在过去15年里，我们几乎从未同时起床过。” 2 温格特夫妇这种情况并非罕见。我们身体的工作原理也具备时钟运行的复杂特性。不同的个体，身体的运行速度也如不同时钟一样，略有差异。温格特习惯早起，而他的妻子则在夜幕降临后才精神饱满。
3 长期以来，行为科学家们把这种差异归结为个人怪癖或早期训练。这一见解到了20世纪50年代后期遭遇一个新理论的挑战。生物学家兼内科医生弗朗兹·哈尔伯格称这个理论为“时间生物学”。在哈佛大学的一间实验室里，哈尔伯格博士发现，因当天从身体抽取血液的时间不同，某些血细胞数量上就有可预见性的差异。细胞数量在一天里某个特定时间多一些，而在12小时后会少一些。他还发现，心率、新陈代谢的速度以及体温变化都可以检测到同样的规律。 4 哈尔伯格这样解释：我们的身体系统运行的周期大约是25小时，速度并非稳定不变。我们有时加速，有时减速。我们的最高效状态只出现在每天某个有限的时间段。哈尔伯格把这种有规律的模式称为“生理节奏”。
5 今天，时间生物学领域大部分最重要的研究由国家航空航天局资助。查尔斯·温格特是航空航天局研究生理学家，也是生理节奏方面的权威。他说，在大部分航天飞机飞行中，生理节奏的原理已经被应用在航天员工作日程的安排上。 6 航天时代的研究在地面上也已经有许多有益的应用。时间生物学家能告诉你，何时吃东西仍然能减肥，一天中什么时间你最有能力去应付最严峻的挑战，什么时候看牙医最不容易感到疼痛，什么时候运动效果最好。温格特说，“人的效率有一个生物法则：若想花费最小的力气获得最好的效果，必须将你的活动要求和身体能力协调起来。”
7 你可以让生理节奏模式为你服务。但是，你必须首先学会识别它们。温格特和他的同事们提出如下的方法来帮你找到你的身体节奏模式。
8 早上起床一小时后，测量体温，然后这一天内每隔四个小时测量一次。最后一次的时间尽可能靠近就寝时间。一天结束前你应该有五次测量的读数。 9 将第一、三、五次的读数相加，记录总和。然后将第二、四次的读数相加，用前面的总和减去这个数字，所得的差大约就是你半夜时分的体温。把它设为第六个读数。
10 现在把这六个读数绘在坐标纸上。表面上看，差异或许极小——有时相差只有十分之一度——但这些差异不可忽视。你很可能会发现，你的体温在凌晨三点到六点之间开始上升，在中午前后达到顶峰。到傍晚时，读数开始下降。读数稳定地下降，到凌晨两点左右达到最低点。
11 当然，个体差异关系重大。你的体温在什么时辰上升？何时达到最高点？何时达到最低点？你一旦熟悉了自己的模式，就可以利用时间生物学的方法增进健康、提高效率。
12 当我们的节奏处于高峰时，我们的体力活做得最好。对于大多数人来说，这样的高峰期会持续大约四个小时。把费力的活动安排在你体温最高的时候。 13 若是脑力活动，时间安排就比较复杂了。诸如数学计算这样高精密度的工作，若在体温处于上升阶段时处理，效果最好。对大多数人来说，这时段就在上午八点到九点之间。相比之下，阅读和思考在下午两点到四点之间进行比较好，这段时间体温通常开始下降。
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14 要想有效节食，在一天内早餐应最丰盛。我们起床后一小时，卡路里燃烧的速度远比晚上快得多。在为期六年、名为“军队饮食调查”的一个研究项目中，哈尔伯格博士、时间生物学家罗伯特·萨森和助理研究员厄纳·哈尔伯格一起监控两组男女成员的食物摄入量。两个组均一日一餐，食物热量为2000卡，但是一个组的食物作早餐，另一个组作晚餐。“所有吃早餐的研究对象都减了体重，”萨森说，“那些吃晚餐的成员，体重要么保持原样要么增加。”
15 在一天不同的时间里，若食物的消化吸收程度存在差异，那么咖啡因、酒精、药物也如此。比如，复方阿司匹林在上午七点到八点之间会产生最强的药效（酒精也一样），而在下午六点到半夜药效最差。咖啡因在下午三点左右作用最强。查尔斯·沃克是佛罗里达州农机大学药学院的院长，他解释说：“当你处于通常的活跃状态时，兴奋剂发挥最大的效力；当你处于自然的镇静或睡眠状态，镇静剂产生最好的效果。”
16 懂得你身体的节奏也可以帮你解决睡眠问题。查看你的体温图表。你的就寝时间应该和你体温的最低点相一致。对大多数人来说，这是在夜里十一点到凌晨两点。
17 纽约蒙特菲奥里医学中心睡眠--觉醒障碍研究所的迈克尔·索皮博士也提供了其它符合生理节奏的睡眠指导：每天晚上同一时间上床睡觉，每天早上同一时间起床，周末也不例外。索皮博士说：“睡眠时间、清醒时间上的不规律性是睡眠问题的最大诱因。”一宿睡眠不足，最佳弥补方式是继续正常的周期，仅此而已。慎用安眠药。索皮博士告诫说：“大多数安眠药的助眠效果不超过两个星期。”况且，药物确实有在血液里积聚的风险。
18 了解身体节奏模式并不能保证良好的健康状况。但是，时间生物学所揭示的是以下两方面的重要性，一是保持生活诸方面的规律性，二是学会和身体的自然节奏保持一致。
Good Usage (Paras. 1-2) the first rays of sunlight is raring to go pulls up the covers
buries her face under the pillow is not uncommon
run at slightly different speeds a morning person
is not at her best until after nightfall
Good Usage (Para. 3)
attributed such differences to in the late 1950s blood cells
varied…in number at a given time of day
Good Usage (Paras. 4-5)
function on an approximately 25-hour cycle
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