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?'

    當你的身體遭遇病痛侵擾時，它都會給出相應的信號──從明顯的發燒癥狀（表明你受到了感染）到不易察覺的腳趾毛發的掉落（可能是血管疾病的早期征兆）.

    有些看起來很可怕的信號其實也許是無關大礙的：糞便呈鮮紅色很可能是因為你吃了甜菜，而不是什么腸道出血。而有些看似無關緊要的信號卻很可能預示著身體有了嚴重的不適。比如，眼瞼上那些小小的黃色腫塊很可能是脂肪沉積物，表明你體內膽固醇過高，更易罹患心臟病。

    其他還有些信號從生物學的角度似乎無法解釋的：眉毛沒有長過眼角也許是因為甲狀腺不夠活躍，耳垂上的斜紋則預示著罹患心臟病的可能性大大提高。

    有些信號似乎有多重含義：大腹便便到底是因為你中年發福呢還是卵巢癌的前兆呢？

    你曾否察覺到身體發出的健康警示信號？問題在于，即便身體明確給出了這些警告，我們很多人卻恍若不覺。醫學作家瓊？利布曼-史密斯（Joan Liebmann-Smith）曾經出現體重急劇下降、掉發、心跳加速、無法入眠的癥狀，她認為這都是因為自己剛生了寶寶后壓力過大所致。而當她向一位精神科專家咨詢失眠問題時，對方告訴她只需"數羊"就可以了。

    直到有一天吃午餐時，一位親戚看著她腫脹的眼睛和咽喉部位的大腫塊說："瓊──你的甲狀腺腫大！"驗血結果證實，她患了甲狀腺機能亢進，這是一種自身免疫疾病，會導致甲狀腺腫大并分泌過多強力激素。

    史密斯說："我身上所有的典型癥狀都有，卻被我忽視了。"身為一名醫學作家，她決定撰寫一本針對非專業人士的書籍，內容是預示重大疾病的身體信號。她與杰奎琳？納爾迪？伊甘（Jacqueline Nardi Egan）──她是一位乳腺癌幸存者──合作撰寫的《從頭到腳的健康信號》（"Body Signs"）于2007年出版，已在26個國家發行。

    史密斯說："我們不希望人們看到身體的這些信號就驚慌失措，倉促得出結論，不過關注自己的身體真的是非常重要。知識就是力量。"

    身上有了腫塊或是哪個地方顏色出現了異常時，不要急著跑去找大夫，請記住，如果這種異常已經有好幾年歷史了，那么它更有可能只是天生的、無傷大雅的。那些平時沒有的跡象和征兆，或是疼痛或身體虛弱的表現更有可能會有問題。（體表的信號能看到或觸摸到；身體內部的信號，比如疼痛，則只有病人自己才能感覺到。）

    從頭到腳仔細檢查病人的身體，尋找此類跡象，是護士培訓的一項重要部分。家庭護理執業醫師蘇珊？丹曼（Susan Denman）在杜克大學護理學院（Duke University School of Nursing）教授身體評估課程，她說："這是病患護理的基礎。"了解這些信號和癥狀的含義在醫生的培訓中占有很大的比重，醫生還需在其整個職業生涯的臨床實踐中不斷完善這個本領。

    不過很多醫生護士都說，病人自己也必須對自身一些新的或者不同尋常的癥狀予以重視。愛達荷州博伊西（Boise）的執業醫生、美國家庭醫生學會（American Academy of Family Physicians）主席泰德？埃珀利（Ted Epperly）說："病人越上心越好。"

    美國醫保體系即將進行重大變革，密切留意自己的身體健康狀況也將變得前所未有地重要起來。初級保健醫生會越來越緊缺，長久的醫患關系會更加難以維系。預防醫學將日益受到重視，患者本身可能會在及早發現疾病、防止疾病惡化方面承擔更大的責任。

    美國每年僅花在糖尿病上的開銷便有約1,740億美元，糖尿病患者的醫藥費平均是其他人的兩倍。糖尿病的前兆在身體的各個部位都有可能出現，包括：牙齦出血、腳痛、頸部及腋下部分皮膚變黑。

    在大規模宣傳教育活動的作用之下，一些最危險的身體信號已廣為人知。多數女性都知道，需要定期檢查胸部是否有腫塊、凹陷、腫脹及乳頭溢液等乳腺癌的征兆，定期接受乳房X光檢查。堪薩斯州普雷恩維爾的家庭醫生健？布魯歐（Jen Brull）說："不是所有的乳房腫塊都是惡性的，不過只要是腫塊都應當去接受檢查。"

    男性也可能罹患乳腺癌，有很多癥狀同女性相似。男性乳房腫大，即通常所說的男子女性型乳房，通常表明男性雌激素與睪丸激素分泌不平衡，這種情況可能是由于青春期發育或年齡越來越大所致──要么就是罹患腎臟疾病或者垂體瘤的征兆。

    有關皮膚癌的宣傳也非常多。加利福尼亞薩克拉門托（Sacramento）的皮膚病學家瑪格麗特？帕森斯（Margaret Parsons）說，觀察皮膚上的色痣時，要看是否有以下五種情況：形狀不規則；邊緣呈鋸齒狀或不規則狀；顏色可疑；大小超過鉛筆上的橡皮頭；凸起且表面不平整。如有上述情況，那么它很可能就是惡性的。如果是基底細胞癌和鱗狀細胞癌，色痣一般呈紅色或粉紅色，表面角化，容易流血。帕森斯醫生說："如果你看到了這樣的痣，一定要去檢查。"

    大肚腩已經成了糖尿病、高血壓、中風、心臟病膽囊疾病以及諸多癌癥高發的信號。腰臀比尤其能說明問題：當男士的腰圍大于臀圍、女士的腰圍超過臀圍的五分之四時，說明其某個臟腑器官的脂肪過高。

    在臨床醫生看來，過高的體重指數（body-mass index）通常都是一個危險的信號。不過原因不明的體重突降也許更值得擔 .布魯爾醫生說："在這個年紀，一般人體重都是增加，假使有人沒有經過任何努力就減肥了，那有可能是患了憂郁癥、胃腸疾病或者吸收不良綜合癥。糖尿病也可能會導致體重下降。"

    有關其他一些疾病信號的宣傳相對要少一些。頭發干枯易斷、指甲易斷、體重驟增或驟減可能是甲狀腺疾病的征兆。身體其他部位毛發脫落可能是因為你步入老齡或絕經期，也可能是代謝紊亂或循環系統出了問題所致。

    帕森斯醫生說："如果我看到病人的中指指甲上有一條橫向的紋路，我會問病人三個月前發生過什么事情──是否有過嚴重的疾病，或者有親近的人亡故了？他們都覺得我太神奇了。"這樣的紋路稱為博氏線（Beau's Line）,在人體承受極大壓力的情況下時有出現。帕森斯醫生說："你的身體太繁忙了，所以你的指甲就小休片刻，然后再接著生長。"

    通過指甲還能看出其他的問題。甲床──即指甲下方的皮膚──發白表明你也許有貧血。護膜附近的指甲呈白色、指尖附近的指甲呈紅色或棕色可能是腎病的征兆。甲床上不規則的棕色或藍色點可能是黑索瘤。指尖呈藍色或者指尖粗大可能是肺部有問題──不過通常來說，如果真有肺病的話，身體會給出其他更為明顯的信號。

    同樣的信號也會出現在腳趾甲上。不過腳部會有其他一些更為重要的信號。丹曼醫生說："腳部會有很多顯示循環系統健康狀況的信號。血管病最早會通過離心臟最遠、最細的血管顯示出來。"

    腳部的麻木感和刺痛感可能預示著循環系統的問題、外部神經的問題或者神經的損傷，神經的損傷通常都是從神經末梢開始的。循環系統及神經的問題都是糖尿病的征兆。因為循環系統有問題，所以即便是腳部最最輕微的刮傷或是潰瘍都非常容易感染；神經系統的麻木則導致這樣的感染容易被忽視，久之便發展為壞疽，需要進行截肢手術。正是出于這個原因，我們要提請糖尿病患者切記每天檢查雙腳，看是否有擦傷或傷口。

    口腔是另外一個了解身體綜合健康狀況的窗口。正因為此，紐約大學牙科學院（New York University's College of Dentistry）與護理學院攜手在學校的免費牙科診所為病人檢查其他的健康問題。牙科診所60%以上的病人符合高血壓的標準，30%患有糖尿病或前驅糖尿病。護理學院臨床實踐事務主任愛德威治？托馬斯（Edwidge Thomas）說："他們是因為牙疼才來看病的，而糖尿病和高血壓的癥狀通常都不是那么明顯。"

    此外還有一些罕見的病例：牙齦會因為白血病而出血、紅腫。神經性貪食會在牙齒后部留下酸性的印記──掉牙也許是營養不良、晚期牙齦病或者長期服用藥物所致。

    還有一些身體健康信號所指向疾病的結論更多的是基于統計數據而非實例得出的。腿短的人更有可能得糖尿病、動脈粥樣硬化及心臟病，這些都是由于在母腹及嬰幼兒時代營養不良所致。多項研究發現，男士的食指比無名指短得越多，他就更好斗。有一種解釋是說因為這樣的人在母腹中時接觸了更多的 丸激素，不過到目前為止，這還只是一個猜測，尚無真憑實據。

    當然，時刻關注自己身體的各種信號只會讓你發現，原來自己有那么多的缺陷。瓊？利布曼-史密斯說："你都沒法相信，我寫這本書時得了多少種病。我得了眼痙攣，我得了腱鞘囊腫、飛蠅幻覺，眼前時常出現巨大的黑影。我的合著者說我經常打嗝，結果發現這是因為我有乳糖不耐癥。我還有胃食管反流病，所以我的聲音一直都很沙啞。誰能想到，胃里的毛病居然會導致嗓音沙啞呢？"