Six symptoms you should never ignore.

If your car's muffler were hanging by a thread, you'd probably rush right over to the mechanic and have it serviced. Yet many people are much more casual about their health, even when symptoms scream as noisily as a muffler in distress. But there are some symptoms you should never ignore.

1. Chest Pain

A hundred years ago "indigestion" was a common cause of death. Today doctors realize that those supposed cases of indigestion were actually the pain and pressure of a heart attack. Even so, many people, especially men, are willing to assume that "it's just something I ate."

Chest pain should never be taken lightly. It is one of the most reliable signs of coronary artery disease. The pain arises when the heart muscle is not getting enough blood or oxygen, and it could mean the start of a heart attack.

"You don't have to be very old to have chest pain," says Masood Akhtar, M.D., director of arrhythmia (irregular heartbeat) service at Sinai Samaritan Medical Center in Milwaukee. "It's a serious symptom, and your doctor must exclude the possibility of coronary disease." Untreated coronary artery disease can lead to sudden death or heart attack.

* When to act: If you experience chest pain that seems unusual or more intense than anything you've experienced before, consult your doctor.

2. Recurrent Headaches

Everyone gets headaches. But when a headache persists and seems resistant to treatment by over-the-counter medication, it's time to seek medical attention.

On rare occasions, headache signals a very serious health threat. Brain tumors and weakened blood vessels in the brain (aneurysms) can trigger the pain. Fortunately, most headaches have less-worrisome origins.

The three most common types of headaches are migraine, chronic tension-type, and cluster headaches. A migraine headache tends to affect one side of the head, and sufferers often feel nauseous. Chronic tension-type headaches recur daily and seem unaffected by aspirin or other pain relievers. Cluster headaches affect primarily males and are concentrated around the eye. Sufferers usually experience several severe headaches a day, with nasal congestion and tearing of the eye.

* When to act: Seek your doctor's help if your headaches are accompanied by a numbness or weakness, vision disturbances, or a loss of sensation. Similarly, if headaches keep you home from work, school, or social activities, or if they are brought on by exertion or sexual or physical activity, see your physician.

3. Vision Disturbances

Any sudden change in our eyesight calls for an immediate visit to an ophthalmologist. Rapid vision loss may indicate a stroke in the retina, the tissue at the back of the eye that forms the "screen" on which images are focused.

Another condition indicated by sudden vision disturbance is a detached retina. Sufferers usually have a sudden vision loss or see flashing lights or a cloud of dust to the side of their eye. These two conditions, with sudden symptoms, may result from aging or from trauma to the eye. They are less common than conditions such as cataracts, in which vision interruption occurs more slowly.

Because vision loss from cataracts is gradual, many people go for years without noticing any change. Untreated cataracts are not life-threatening, but they may reduce the quality of your life.

Another major eye disease that results in gradual vision loss is glaucoma.

* When to act: Be wary of any sudden or unusual eye-sight symptoms, including halos around lights, inability to see in dim light, and flashes of light or blurred vision.

4. Breast Discharge

For years women have been urged to examine their breasts each month for lumps that may indicate breast cancer. But another symptom of breast cancer is a milky white discharge from the nipple. Leaking from the nipple may indicate that a tumor has infiltrated the breast's milk ducts.

Breast cancer can occur in men as well. A man should see a doctor if he detects a thickening of tissue around his breast or notices any other abnormalities.

* When to act: See a doctor immediately if you detect any type of breast discharge, including blood. Also, report any changes in your breast, including a retracted nipple, misshapen areola (the dark area around the nipple), or a change in breast shape or skin texture.

5. A Changing Mole

Most moles remain moles. But on occasion, particularly in people who have had burning exposures to the sun, a mole will become the starting point for cancer. Malignant melanoma is a potentially deadly form of skin cancer.

Found early, melanomas can be cut from the skin. Left untreated, they're life-threatening.

* When to act: See your doctor any time an existing mole changes shape or exudes a discharge. For complete safety, examine your legs, chest, arms, and upper back periodically, and see your doctor immediately if a new mole shows up.

Cancerous moles are often larger than one-fourth inch across and are usually not symmetrical or evenly colored.

6. Fainting Spells

Several conditions lead to fainting spells. The most common relates to circulation. The temporary loss of consciousness occurs when the brain doesn't get enough oxygen-rich blood. The heart may be beating too fast (and without enough pressure) or too slowly. Another culprit: blood may be pooling in the lower parts of the body.

* When to act: Repeated fainting, regardless of how quickly it passes, should be evaluated by your doctor.