Ask readers of this newspaper if they're getting adequate sleep, and many would probably say 'Ha!'

    Twenty percent of Americans sleep less than six hours a night, and nearly one-third have lost sleep worrying about financial concerns, according to the National Sleep Foundation, which recommends that adults get seven to nine hours. 'Our society thinks sleep is for slackers -- or suckers,' says Darrel Drobnich, the organization's chief program officer.

    But all that lost sleep is taking an insidious toll. Chronic, inadequate sleep raises the risk of cardiovascular disease, depression, diabetes and obesity. It impairs cognitive function, memory and the immune system and causes more than 100,000 motor-vehicle accidents a year. Sleep deprivation also changes the body's metabolism, making people eat more and feel less satisfied.

    Studies presented at the American Association of Sleep Medicine's annual meeting in Seattle recently also found that inadequate sleep is associated with lower GPAs among college students and with elevated levels of visfatin, a hormone secreted by belly fat that is associated with insulin resistance.

    What many people don't realize is that even if they log respectable time in bed （known as TIB among sleep researchers）, they may be getting poor-quality sleep, with not enough of the restorative phases. REM, the Rapid Eye Movement phase in which dreaming occurs, is crucial for consolidating memories, learning, creativity, problem-solving and emotional balance. Deep, or slow-wave sleep, when the body secretes human growth hormone, is critical for development and physical repair. Both REM and deep sleep decline with age and are highly vulnerable to disruptions, from caffeine and alcohol to anxiety and a variety of sleep disorders.

    One tip-off that you haven't gotten enough restorative sleep is trouble waking up and excessive daytime sleepiness （a condition known as EDS）. 'People say, 'Oh, I don't have a sleep problem. I can fall asleep anywhere, anytime' -- but that means you are excessively sleepy,' says Charles Czeisler, a professor of sleep medicine at Harvard Medical School.

    Other symptoms of sleep deprivation include mood changes, difficulty focusing or remembering and a chronic need for caffeine, which can then create a vicious circle of dependence and disruption. That would be me.

    Finding out what's going on in your sleep generally requires spending the night in a professional sleep lab hooked up to lots of wires and monitors. But I've been testing a new home-sleep monitor called the Zeo Personal Sleep Coach that lets people track their sleep patterns nightly in their own bedrooms.

    You sleep wearing a soft headband with sensors that monitor your brain waves and send signals wirelessly to a device that looks like a sleek clock radio. It displays whether you are awake or in light sleep, deep sleep, or REM sleep, in real time, all through the night.

    'If you can measure it, you can manage it,' says Stephan Fabregas, one of two recent Brown University graduates who invented the Zeo because they were looking for a way to wake up feeling less groggy after late nights.

    I knew I wasn't getting enough TIB, but I was stunned to see how little of my time in bed I was actually asleep. The Zeo showed that I woke up numerous times and was awake for long stretches of the night, without having any recollection. （Perception of time is often distorted at night -- many people with insomnia actually sleep more than they think they do.） Even though I was in bed for six or seven hours each night, I was averaging only about four hours of real sleep and very little REM or deep sleep. No wonder I feel so tired!

    The Zeo stores the information on a memory card you can upload to a Web site, which helps track your sleep patterns and sends daily coaching tips for getting better sleep. The $399 device comes with six months of daily email coaching, which can be extended at a cost of $99 for each additional six months. （Currently, it's available only online at www.myzeo.com.）

    To help you keep track of your sleep, the Zeo also gives you a 'ZQ' score every morning, based on the quantity and quality of your sleep the night before. There's no ideal ZQ -- you're comparing your own score from night to night. But the average for people in their 20s is 86; for those in their 40s, it is 74; and for those in their 50s, it is 67, since sleep quality declines with age.

    My ZQs bounced from the 40s to a dismal 15 the first week. Switching to decaf after 3 p.m. and making an effort to get to bed earlier helped me bring my score into the 50s the second week. （'Having caffeine even first thing in the morning can induce changes in brain activity during sleep,' says Kenneth Wright, director of the Sleep and Chronobiology Lab at the University of Colorado at Boulder and one of Zeo's scientific advisers.） I also noticed that the nights when I had the longest stretches of wakefulness were those when my column was due -- probably a sign that I was still thinking about it long after turning in.

    Everybody's sleep and sleep disruptors are different. Todd Johnson, a 40-year-old border-patrol agent in Caribou, Maine, and one of ZEO's early testers, found that reading before he went to bed helped reduce his wake time and bring his ZQ from the 20s into the 60s. 'You can try something that night and see the results in the morning,' he says. Another early tester, Tim Guirl, who teaches at a community college in Seattle, found that he had more restorative sleep if he didn't exercise too close to bedtime and eliminated a large late-night snack.

    Other recommendations from Zeo include reducing noise, light and disruptive influences like pets in the bedroom; having a 'power-down' hour before bedtime with no email, no Internet use, no cellphones and no BlackBerrys; and keeping a consistent sleep schedule. And if you find yourself awake and worrying, Zeo recommends getting out of bed and writing down what you're thinking about in a 'worry journal.'

    The Zeo's brain-wave results have proven similar to those from professional sleep labs -- but only about 140 people have tested it so far. And the Zeo isn't designed to diagnose actual sleep disorders, which plague an estimated 70 million Americans -- you need to see a doctor for that.

    To see if something besides drinking coffee and thinking great thoughts was affecting my sleep, I underwent a sleep study at the Sleep Health Center connected with Brigham and Women's Hospital in Brighton, Mass. A polysomnography, as such tests are called, measures brain waves like the Zeo, but also heart rate, respiratory rate, oxygen saturation, body positions and movements. It took about 45 minutes to have all of the sensors and wires attached -- and then a little longer to get comfortable enough to sleep.

    To my surprise, the study found that I had a fairly severe case of Periodic Limb Movements, episodes of involuntary muscle movements in the night. About 10% of adults have PLMs. Many don't even notice; sleep partners are often bothered more than the sleepers themselves. But PLMs can be very disruptive if they are accompanied by arousals from sleep. I was averaging 42 arousals per hour. According to David White, another Harvard sleep physician who prescribed the study for me, PLMs can be due to an iron deficiency or medication side effects, and they are often related to 'restless-leg syndrome,' which causes an irresistible urge to move the legs, day or night. Medications like Requip can minimize the movements; I'm going to give them a try.

    The study also showed I had some obstructive sleep apnea, in which the airway narrows, especially when the muscles relax in sleep. People with OSA stop breathing momentarily until a lack of oxygen alerts the brain, which wakes them up with a gasp. These mini arousals can occur as often as 70 times an hour, leaving the sufferer exhausted and at risk for heart disease, stroke and atherosclerosis. An estimated 4% of men and 2% of women have OSA. One telltale sign is having a shirt-collar size larger than 17 inches. Another sign is loud snoring, although I certainly don't do that. （'Women never snore -- they all deny it,' says Dr. White.）

    The most effective treatment is a Continuous Positive Airway Pressure machine, which blows air through the nose to keep the airway open. My OSA isn't that bad -- yet. Other remedies include a dental appliance that helps prop the airway open and losing weight, which helps reduce the airway blockage.

    Dr. White is also chief medical officer for Philips Home Healthcare, which makes a watch-like monitor, called an Actiwatch, that tracks whether the wearer is moving or still, roughly corresponding with sleep. The Actiwatch doesn't show sleep phases; it generally diagnoses problems with jet lag and body clocks. I wore one for a week, and although I'm still a night owl, it showed nothing amiss in that area.

    All in all, 'there are plenty of ways you can improve your sleep,' Jason Donahue, another Zeo founder, tells me cheerily. This week, I'm starting in on Zeo's tips on keeping disturbances in the bedroom to a minimum. The dog may have to find a new place to sleep.

    如果问《华尔街日报》的读者们睡眠是否充足，许多人或许会回答说："哈！"

    美国睡眠基金会（National Sleep Foundation）建议成年人每天的睡眠时间达到7至9个小时。不过根据该基金会的数据，20%的美国人每晚睡眠时间不足6小时，近三分之一的人因担心财务状况失眠。该机构负责人德洛？布尼奇（Darrel Drobnich）说，"美国社会认为只有懒虫──或者是傻瓜才会睡大觉。"

    不过睡眠不足正在严重损害着人类的健康。长期的睡眠不足会加大患心血管病、抑郁症、糖尿病和肥胖的风险，损害认知功能、记忆力和免疫系统，每年还会引发超过10万起机动车事故。睡眠不足还会改变身体的新陈代谢节奏，导致食量增大、饮食带来的满足感下降。

    美国睡眠医学学会（American Association of Sleep Medicine）最近在西雅图年会上公布的一些研究显示，睡眠不足会导致大学生GPA成绩下降，而且还与内脂素水平上升有关。内脂素是一种由肚子上的脂肪组织分泌的荷尔蒙，而这些脂肪与抗胰岛素有关。

    许多人没有意识到的是，即使他们躺在床上的时间足够多（睡眠研究者称之为在床时间TIB,Time in Bed）,也可能没有得到高质量的睡眠，不足以恢复精力。出现梦境的快速眼动睡眠期（REM）对于加强记忆力、学习能力、创造力、解决问题和平衡情绪的能力非常关键。深层睡眠，亦称慢波睡眠（slow-wave sleep）对于身体的生长和肌体恢复至关重要。而且在这一阶段，人体分泌出身体生长所需的荷尔蒙。快速眼动睡眠和深层睡眠时间都会随着年龄的增长而减少，而且对于从咖啡因、酒精，到焦虑和一系列睡眠障碍的干扰都非常敏感。

    没有得到足够的恢复性睡眠的一个特征是早上起不来，白天睡不醒（这一症状称作EDS）."人们会说，'哦，我没有睡眠问题。我随时随地都能睡着。'──不过这意味着你非常困倦，"哈佛医学院睡眠医学教授查尔斯？切斯勒（Charles Czeisler）说。

    其他睡眠不足的症状表现包括情绪多变、难以集中注意力、记忆力衰退和长期依赖咖啡因，而这些表现又造成了依赖和干扰的恶性循环。我就是这样的人。

    要想知道自己的睡眠情况，人们通常需要在专业的睡眠实验室呆上一晚上，身上接满各种线路和监视器。不过，我最近在家测试一种名为Zeo Personal Sleep Coach的新型家庭睡眠监测仪。它让人们可以在自己的卧室里跟踪自己夜晚的睡眠状况。

    你需要在睡觉的时候戴上一条柔软的发带。发带上面装有用来监测脑波的传感器，它能将信号无线传递到一个看上去像电子钟收音机的装置上去。该装置能够实时显示你的睡眠状态：比如你是醒着，处在浅睡、深度睡眠还是快速眼动睡眠状态。

    斯蒂芬？法布里加斯（Stephan Fabregas）说，"如果可以衡量睡眠，那么你就能够控制睡眠。"他和另外一名同样也是新近从布朗大学（Brown University）毕业的学生一道发明了Zeo.他们的初衷是想找到一个解决熬夜之后早上醒来时昏昏沉沉的办法。

    我心里清楚自己躺在床上的时间不够多，不过当我知道自己每天真正花在睡眠上的时间只有那么一点点，还是大吃了一惊。Zeo显示，我夜里醒来过很多很多次，而且在夜晚大段大段的时间里都没有睡着，而这些我却完全不记得。（时间感在夜晚通常会变得不准确──许多失眠者的睡眠时间实际上比他们预想得要多。）即便我每晚在床上的时间有6至7个小时，真正的睡眠时间平均下来也只有大约4个小时，而快速眼动睡眠和深层睡眠时间更是少之又少。难怪我会感觉疲劳！

    Zeo会将所有这些信息储存在一张记忆卡上，然后将信息上传到一个网站。该网站可以帮助你跟踪你的睡眠模式，还会每天发送指导建议教你如何改善睡眠。Zeo售价399美元，购买商品附送半年的每日电子邮件指导，额外订阅电子邮件的价格为每半年99美元（眼下，该服务仅通过www.myzeo.com网站在线提供）

    为了帮助你跟踪自己的睡眠情况，Zeo还会在每天早上根据前一晚的睡眠时间和睡眠质量为你评出一个"睡商（ZQ）"分数。睡商并没有优劣之分──你所要做的只是和自己作比较。不过，二十几岁年轻人的平均ZQ分是86,四十几岁的平均分是74,五十几岁67分，这是因为睡眠质量会随着年龄的增加而下降。

    我的睡商分数在第一个星期从40多分下降到令人沮丧的15分。下午三点以后改喝不含咖啡因的咖啡、尽量早点儿休息让我在第二周将分数提高到了50多分。（"即便每天早上一醒来就喝有咖啡因的饮品，在晚上睡觉时大脑活动还是会有变化，" 科罗拉多大学波尔得分校（ University of Colorado at Boulder）睡眠和生物钟实验室负责人肯尼思？怀特（Kenneth Wright）说，他也是Zeo的科学顾问之一。）我还注意到，我晚上失眠时间最长的时候都在我的专栏文章截稿日──或许这意味着我在交稿很久以后还在想着稿件的事。

    每个人的睡眠状况和影响睡眠的因素都不一样。40岁的托德？约翰逊（Todd Johnson）是美国缅因州的边境巡警，也是Zeo早期的测试者之一。他发现，每晚睡觉前读书有助于自己的睡眠，他的睡商分数也因此从二十几分提高到了六十几分。"你可以晚上尝试做些什么事情，然后早上看看效果如何，"他说。另一位早期测试者蒂姆？圭尔（Tim Guirl）在西雅图的一个社区大学教书。他发现，如果自己不在睡觉前锻炼，并取消晚上那一大份夜宵的话，就会得到更多恢复性的睡眠。

    Zeo的其他建议还包括：减少噪音、灯光和其他因素的干扰，比如卧室中的宠物；在睡觉前有一小时"不插电"的时间，也就是不收发电子邮件、不上网、不打手机、不用黑莓（BlackBerry）;保持一个固定的睡眠时间。如果你发现自己忧心忡忡、睡不着觉，Zeo建议你起床，并在"忧虑日记"里记下自己为什么担心。

    事实证明，Zeo的脑波结果和专业睡眠实验室的结论很接近──不过到目前为止只有大约140人接受过Zeo测试。此外，Zeo并不能用来诊断困扰七千万美国人的真正的睡眠失调──你需要去看医生。

    为了搞明白除了喝咖啡和思考"伟大思想"之外，还有什么事情影响我的睡眠，我到位于马萨诸塞州布莱顿（Brighton）的布里格姆妇女医院（Brigham and Women's Hospital）睡眠健康中心进行了一次睡眠测试。多导睡眠监测能够像Zeo一样测量脑波，此外还可以测试心率、呼吸频率、氧饱和度、身体姿态和动态情况。将所有监控仪和线路连接好花了大约45分钟的时间──我用了更长的时间才进入梦乡。

    让我惊讶的是，测试发现，我有相当严重的周期性肢体运动障碍──一种在夜间反复发生的不自觉的肌肉运动。大约10%的成年人患有周期性肢体运动障碍。许多人根本不知道自己有这个毛病；同床者往往比睡眠者更受干扰。不过，如果伴随有突然的觉醒，那么周期性肢体运动障碍造成的干扰会大得多。我每小时平均的觉醒次数是42次。根据另一位哈佛大学睡眠学家大卫？怀特（David White）的看法，周期性肢体运动障碍有可能是因为体内缺少铁质或者是药物治疗的副作用所致，这种症状还通常和"不宁腿综合症"有关。不宁腿综合症迫使肢体发生不自主的运动，无论白天还是黑夜。Requip等药物可以最大化地减少肢体的活动；我会试试这种药。

    测试还显示，我有睡眠呼吸暂停的症状，这是因为呼吸道受到松弛肌肉的阻塞。患有睡眠呼吸暂停的人呼吸会突然停止，直到缺氧的信号传递到大脑，将你唤醒。这些微觉醒每小时可以出现70次之多，导致患者精疲力竭，还有突发心脏病、中风和患动脉硬化的风险。大约有4%的男性和2%的女性患有睡眠呼吸暂停。患病的一个信号是衬衣领口号码大于17英寸。另一个信号是鼾声如雷，尽管我肯定不属于这一情况。（怀特说，"女人们从不打鼾──她们都不承认自己打鼾。"）

    最有效的治疗方法是使用持续正压通气机（Continuous Positive Airway Pressure）,通过将空气送入鼻腔来保持呼吸道畅通。我的睡眠呼吸暂停还没有那么严重──起码到现在为止。其他治疗方法包括使用牙科器械和减肥，前者能够帮助撑开呼吸道，后者能缓解呼吸道的阻塞。

    怀特还是飞利浦家庭医疗保健（Philips Home Healthcare）的首席医疗官。飞利浦生产一款名为Actiwatch、外型类似手表的监控器。它能够追踪佩戴者是在动还是保持静止，大致和他的睡眠相对应。Actiwatch并不能显示睡眠阶段；但能够用于诊断时差和生物钟问题。我佩戴了一个星期，尽管我还是个夜猫子，Actiwatch显示我在这些方面没有异常。

    总而言之，"改善睡眠的方式有很多，"Zeo另一位创始人詹森？多纳赫（Jason Donahue）高兴地对我说。从现在开始，我采纳了Zeo尽量减少卧室干扰的建议。我的狗或许需要找到个新地方去睡觉了。