The body speaks volumes about what ails it -- from obvious warnings like a fever that accompanies an infection to subtle clues like losing hair on the toes, which can be an early sign of vascular disease.

    Some signs that seem alarming may actually be harmless: Bright-red stools are more likely to come from eating beets than from intestinal bleeding. But some that seem minor can warn of a serious disorder. Small yellow bumps on the eyelid, for instance, may be fatty deposits that signal high cholesterol, which in turn raises the risk of heart disease.

    Other signs seem to make no logical biological sense: Eyebrows that no longer extend over the corners of the eyes can indicate an underactive thyroid, and a diagonal crease in the earlobe seems to herald a heightened risk of heart attack.

    Some body signs can have a confusing range of meanings: Does that bulging tummy signify middle-aged spread or the beginning of ovarian cancer?

    The problem is that many of us don't recognize the warnings, even when they're staring us in the face. Medical writer Joan Liebmann-Smith was losing weight rapidly. Her hair was falling out. Her heart was racing, and she couldn't sleep. She chalked up her symptoms to the stress of having a new baby, while a psychiatrist she consulted for insomnia told her to just 'count sheep.'

    Over lunch one day, a relative looked at her bulging eyes and the big lump in her throat and said, 'Joan -- you have a goiter!' A blood test confirmed that she had an advanced case of Grave's disease, an autoimmune disorder that causes the thyroid gland to swell and produce too much of the powerful hormone.

    'I had all the classic signs, and I ignored them,' says Ms. Liebmann-Smith, a medical writer, who resolved to write a guide for laymen to the warning signs of serious illnesses. 'Body Signs' -- written with Jacqueline Nardi Egan, a breast-cancer survivor -- came out in 2007 and has since been published in 26 countries.

    'We don't want people to panic and jump to conclusions,' Ms. Liebmann-Smith says. 'But it's important to pay attention to your body. Knowledge is power.'

    Before you race off to the doctor for every lump or discoloration, remember that anomalies you've had for years are more likely to be a harmless part of your genetic makeup. Signs and symptoms that are unusual for you, or painful or debilitating, are more likely to be significant. （Signs are external indicators that can be seen or felt; symptoms are internal sensations, such as pain, that only the patient can perceive.）

    Examining a patient from head to toe for such indicators is a key part of every nurse's training. 'It's the foundation of patient care,' says Susan Denman, a family nurse practitioner who teaches physical assessment at the Duke University School of Nursing. Knowing how to interpret all those signs and symptoms takes up much of a doctor's education and is refined over a lifetime of clinical practice.

    But many doctors and nurses alike say that patients, too, should be vigilant for anything new or unusual about their own bodies. 'The more engaged patients can be, the better,' says Ted Epperly, president of the American Academy of Family Physicians, who maintains a practice in Boise, Idaho.

    With major changes to the nation's health-care system looming, it may be more important than ever for people to keep track of their own physical health. Primary-care doctors could become increasingly pressed for time, and long-term doctor-patient relationships may be harder to sustain. The growing emphasis on preventive medicine may also place more responsibility on patients to head off illnesses before they become serious.

    Diabetes alone costs the nation an estimated $174 billion annually; people with diabetes have more than twice the average medical bills than those without. Signs of diabetes show up all over the body, from bleeding gums to tingling feet to darkened skin patches on the neck and underarms.

    Some of the most worrisome body signs are already well known, thanks to extensive education campaigns. Most women know to check their breasts regularly for lumps, dimples, swelling and discharge that can signify cancer, and to have regular mammograms. 'Not all breast lumps are bad, but they all need to get checked out,' says Jen Brull, a family physician in Plainville, Kan.

    Men can develop breast cancer too, with many of the same symptoms. Enlarged breasts in men, known as gynecomastia, generally indicates an imbalance of estrogen and testosterone, which can occur from puberty or aging -- or it could be a sign of kidney disease, or a pituitary tumor.

    Skin cancers have also gotten significant publicity. When evaluating a spot, remember 'ABCDE,' says Margaret Parsons, a dermatologist in Sacramento, Calif.: It may be malignant if it has A, for an asymmetrical shape; B for a jagged or irregular border; C for a suspicious color; D for a diameter larger than a pencil eraser; and E for being elevated and uneven. Basal-cell carcinomas and squamous-cell carcinomas tend to be red to pink and crusty, and bleed easily. 'If you see anything like that, you should be checked,' Dr. Parsons says.

    Excess belly fat is becoming notorious as a sign of a heightened risk of diabetes, high blood pressure, stroke, heart disease, gall-bladder disease and numerous cancers. Waist-to-hip ratios are especially telling: If a man's waist is larger than his hips, or a women's waist is more than four-fifths her hip circumference, that's a sign that dangerous visceral fat is surrounding an abdominal organ.

    A high body-mass index is a red flag in general to clinicians. But sudden, unexplained weight loss can be even more worrisome. 'In this day and age, people tend to gain weight. If somebody loses weight without trying, that could be a sign of depression or a gastrointestinal illness or a malabsorption syndrome. Even diabetes can cause you to lose weight,' says Dr. Brull.

    Many other signs of possible illness are less well-publicized. Thyroid disease can manifest itself in dry, brittle hair, brittle nails, and weight gain or loss. Losing hair on the rest of your body could be aging or menopause, or a metabolic disorder or circulatory problems.

    'If I see a patient with a horizontal line through the middle of the fingernails, I'll ask what happened three months ago -- were they horribly ill or did someone die? They think I'm brilliant,' says Dr. Parsons. The markings, called Beau's Lines, sometimes appear when the body is particularly stressed. 'Your body is busy, so your nails take a little break and then start growing again,' Dr. Parsons says.

    Nails tell other tales as well. White nail beds -- the skin underneath the nail -- can signify anemia. Nails that are white near the cuticle and red or brown near the tip can be a sign of kidney disease. Irregularly shaped brown or blue spots in the nail bed can be melanomas. Fingertips that are blue or clubbed can be a sign of lung disease -- although generally, there would be more significant signs as well.

    Many of the same signs occur in toenails. But the feet are critical for other reasons. 'Feet tell you a huge amount about the health of the circulation,' says Dr. Denman, the Duke nursing instructor. 'The first place that vascular disease can show up is where the blood vessels are the smallest and the farthest away from the heart.'

    Circulatory problems can manifest themselves as numbness and tingling in the feet; so can peripheral neuropathy, or damage to the nerves that often begins at the extremities. Both are signs of uncontrolled diabetes. With circulation compromised, even a minor scratch or sore on the feet can become infected easily; lack of sensation can make it easy to ignore, and gangrene can set in, requiring amputation. That's why people with diabetes are urged to check their feet every day for any kind of scratch or lesion.

    The mouth provides another window into overall health. That's what inspired New York University's College of Dentistry to team up with its College of Nursing to check patients at the university's free dental clinic for other health-related issues. More than 60% of the patients referred from the dental clinic met the criteria for hypertension, and 30% had diabetes or pre-diabetes. 'The tooth pain brings them in. Diabetes and hypertension are often silent diseases,' says Edwidge Thomas, the nursing school's director of clinical practice affairs.

    In rarer cases, gums can bleed and become inflamed from leukemia. Bulimia can leave telltale acid marks on the backs of teeth -- and missing teeth can be a sign of poor nutrition, advanced gum disease or long-term drug use.

    Some body signs are more statistical correlations than causal relationships. Short leg length has been linked to a higher risk for diabetes, atherosclerosis and heart disease, which could all be due to poor nutrition in utero or early childhood. Several studies have found that the shorter a man's index finger in relation to his ring finger, the more aggressive he's likely to be. One possible explanation is exposure to testosterone in the womb, but so far, that remains more a curiosity than a clue.

    Of course, being vigilant about your body signs can show you just how imperfect you are. 'You wouldn't believe what else I came down with writing the book,' Ms. Liebmann-Smith says. 'I developed an eye tic. I had a ganglion cyst and giant floaters. And my co-author complained that I was belching a lot. It turned out I was lactose intolerant. I also had GERD [gastroesophageal reflux disease], so I was hoarse all the time. Who would have thought that something to do with your stomach would cause hoarseness?'

    当你的身体遭遇病痛侵扰时，它都会给出相应的信号──从明显的发烧症状（表明你受到了感染）到不易察觉的脚趾毛发的掉落（可能是血管疾病的早期征兆）.

    有些看起来很可怕的信号其实也许是无关大碍的：粪便呈鲜红色很可能是因为你吃了甜菜，而不是什么肠道出血。而有些看似无关紧要的信号却很可能预示着身体有了严重的不适。比如，眼睑上那些小小的黄色肿块很可能是脂肪沉积物，表明你体内胆固醇过高，更易罹患心脏病。

    其他还有些信号从生物学的角度似乎无法解释的：眉毛没有长过眼角也许是因为甲状腺不够活跃，耳垂上的斜纹则预示着罹患心脏病的可能性大大提高。

    有些信号似乎有多重含义：大腹便便到底是因为你中年发福呢还是卵巢癌的前兆呢？

    你曾否察觉到身体发出的健康警示信号？问题在于，即便身体明确给出了这些警告，我们很多人却恍若不觉。医学作家琼？利布曼-史密斯（Joan Liebmann-Smith）曾经出现体重急剧下降、掉发、心跳加速、无法入眠的症状，她认为这都是因为自己刚生了宝宝后压力过大所致。而当她向一位精神科专家咨询失眠问题时，对方告诉她只需"数羊"就可以了。

    直到有一天吃午餐时，一位亲戚看着她肿胀的眼睛和咽喉部位的大肿块说："琼──你的甲状腺肿大！"验血结果证实，她患了甲状腺机能亢进，这是一种自身免疫疾病，会导致甲状腺肿大并分泌过多强力激素。

    史密斯说："我身上所有的典型症状都有，却被我忽视了。"身为一名医学作家，她决定撰写一本针对非专业人士的书籍，内容是预示重大疾病的身体信号。她与杰奎琳？纳尔迪？伊甘（Jacqueline Nardi Egan）──她是一位乳腺癌幸存者──合作撰写的《从头到脚的健康信号》（"Body Signs"）于2007年出版，已在26个国家发行。

    史密斯说："我们不希望人们看到身体的这些信号就惊慌失措，仓促得出结论，不过关注自己的身体真的是非常重要。知识就是力量。"

    身上有了肿块或是哪个地方颜色出现了异常时，不要急着跑去找大夫，请记住，如果这种异常已经有好几年历史了，那么它更有可能只是天生的、无伤大雅的。那些平时没有的迹象和征兆，或是疼痛或身体虚弱的表现更有可能会有问题。（体表的信号能看到或触摸到；身体内部的信号，比如疼痛，则只有病人自己才能感觉到。）

    从头到脚仔细检查病人的身体，寻找此类迹象，是护士培训的一项重要部分。家庭护理执业医师苏珊？丹曼（Susan Denman）在杜克大学护理学院（Duke University School of Nursing）教授身体评估课程，她说："这是病患护理的基础。"了解这些信号和症状的含义在医生的培训中占有很大的比重，医生还需在其整个职业生涯的临床实践中不断完善这个本领。

    不过很多医生护士都说，病人自己也必须对自身一些新的或者不同寻常的症状予以重视。爱达荷州博伊西（Boise）的执业医生、美国家庭医生学会（American Academy of Family Physicians）主席泰德？埃珀利（Ted Epperly）说："病人越上心越好。"

    美国医保体系即将进行重大变革，密切留意自己的身体健康状况也将变得前所未有地重要起来。初级保健医生会越来越紧缺，长久的医患关系会更加难以维系。预防医学将日益受到重视，患者本身可能会在及早发现疾病、防止疾病恶化方面承担更大的责任。

    美国每年仅花在糖尿病上的开销便有约1,740亿美元，糖尿病患者的医药费平均是其他人的两倍。糖尿病的前兆在身体的各个部位都有可能出现，包括：牙龈出血、脚痛、颈部及腋下部分皮肤变黑。

    在大规模宣传教育活动的作用之下，一些最危险的身体信号已广为人知。多数女性都知道，需要定期检查胸部是否有肿块、凹陷、肿胀及乳头溢液等乳腺癌的征兆，定期接受乳房X光检查。堪萨斯州普雷恩维尔的家庭医生健？布鲁欧（Jen Brull）说："不是所有的乳房肿块都是恶性的，不过只要是肿块都应当去接受检查。"

    男性也可能罹患乳腺癌，有很多症状同女性相似。男性乳房肿大，即通常所说的男子女性型乳房，通常表明男性雌激素与睾丸激素分泌不平衡，这种情况可能是由于青春期发育或年龄越来越大所致──要么就是罹患肾脏疾病或者垂体瘤的征兆。

    有关皮肤癌的宣传也非常多。加利福尼亚萨克拉门托（Sacramento）的皮肤病学家玛格丽特？帕森斯（Margaret Parsons）说，观察皮肤上的色痣时，要看是否有以下五种情况：形状不规则；边缘呈锯齿状或不规则状；颜色可疑；大小超过铅笔上的橡皮头；凸起且表面不平整。如有上述情况，那么它很可能就是恶性的。如果是基底细胞癌和鳞状细胞癌，色痣一般呈红色或粉红色，表面角化，容易流血。帕森斯医生说："如果你看到了这样的痣，一定要去检查。"

    大肚腩已经成了糖尿病、高血压、中风、心脏病胆囊疾病以及诸多癌症高发的信号。腰臀比尤其能说明问题：当男士的腰围大于臀围、女士的腰围超过臀围的五分之四时，说明其某个脏腑器官的脂肪过高。

    在临床医生看来，过高的体重指数（body-mass index）通常都是一个危险的信号。不过原因不明的体重突降也许更值得担 .布鲁尔医生说："在这个年纪，一般人体重都是增加，假使有人没有经过任何努力就减肥了，那有可能是患了忧郁症、胃肠疾病或者吸收不良综合症。糖尿病也可能会导致体重下降。"

    有关其他一些疾病信号的宣传相对要少一些。头发干枯易断、指甲易断、体重骤增或骤减可能是甲状腺疾病的征兆。身体其他部位毛发脱落可能是因为你步入老龄或绝经期，也可能是代谢紊乱或循环系统出了问题所致。

    帕森斯医生说："如果我看到病人的中指指甲上有一条横向的纹路，我会问病人三个月前发生过什么事情──是否有过严重的疾病，或者有亲近的人亡故了？他们都觉得我太神奇了。"这样的纹路称为博氏线（Beau's Line）,在人体承受极大压力的情况下时有出现。帕森斯医生说："你的身体太繁忙了，所以你的指甲就小休片刻，然后再接着生长。"

    通过指甲还能看出其他的问题。甲床──即指甲下方的皮肤──发白表明你也许有贫血。护膜附近的指甲呈白色、指尖附近的指甲呈红色或棕色可能是肾病的征兆。甲床上不规则的棕色或蓝色点可能是黑索瘤。指尖呈蓝色或者指尖粗大可能是肺部有问题──不过通常来说，如果真有肺病的话，身体会给出其他更为明显的信号。

    同样的信号也会出现在脚趾甲上。不过脚部会有其他一些更为重要的信号。丹曼医生说："脚部会有很多显示循环系统健康状况的信号。血管病最早会通过离心脏最远、最细的血管显示出来。"

    脚部的麻木感和刺痛感可能预示着循环系统的问题、外部神经的问题或者神经的损伤，神经的损伤通常都是从神经末梢开始的。循环系统及神经的问题都是糖尿病的征兆。因为循环系统有问题，所以即便是脚部最最轻微的刮伤或是溃疡都非常容易感染；神经系统的麻木则导致这样的感染容易被忽视，久之便发展为坏疽，需要进行截肢手术。正是出于这个原因，我们要提请糖尿病患者切记每天检查双脚，看是否有擦伤或伤口。

    口腔是另外一个了解身体综合健康状况的窗口。正因为此，纽约大学牙科学院（New York University's College of Dentistry）与护理学院携手在学校的免费牙科诊所为病人检查其他的健康问题。牙科诊所60%以上的病人符合高血压的标准，30%患有糖尿病或前驱糖尿病。护理学院临床实践事务主任爱德威治？托马斯（Edwidge Thomas）说："他们是因为牙疼才来看病的，而糖尿病和高血压的症状通常都不是那么明显。"

    此外还有一些罕见的病例：牙龈会因为白血病而出血、红肿。神经性贪食会在牙齿后部留下酸性的印记──掉牙也许是营养不良、晚期牙龈病或者长期服用药物所致。

    还有一些身体健康信号所指向疾病的结论更多的是基于统计数据而非实例得出的。腿短的人更有可能得糖尿病、动脉粥样硬化及心脏病，这些都是由于在母腹及婴幼儿时代营养不良所致。多项研究发现，男士的食指比无名指短得越多，他就更好斗。有一种解释是说因为这样的人在母腹中时接触了更多的 丸激素，不过到目前为止，这还只是一个猜测，尚无真凭实据。

    当然，时刻关注自己身体的各种信号只会让你发现，原来自己有那么多的缺陷。琼？利布曼-史密斯说："你都没法相信，我写这本书时得了多少种病。我得了眼痉挛，我得了腱鞘囊肿、飞蝇幻觉，眼前时常出现巨大的黑影。我的合着者说我经常打嗝，结果发现这是因为我有乳糖不耐症。我还有胃食管反流病，所以我的声音一直都很沙哑。谁能想到，胃里的毛病居然会导致嗓音沙哑呢？"