It's a stereotype, to be sure, but one based on some truth. Just as men won't stop and ask for directions even when they are lost, they also won't go to the doctor even when they suspect something is wrong with their health.

Whether it's just being macho or a whopping case of denial, they even ignore the big and obvious symptoms. "I call it the ostrich phenomenon," Dr. Harvey Simon, associate professor of medicine at Harvard Medical School and editor of the Harvard Men's Health Watch newsletter, told CNN. "Guys are very prone to sticking their head in the sand and hoping when they emerge everything will be back to normal. It's a very, very bad idea."

CNN medical correspondent Elizabeth Cohen polled several medical doctors to find out the most important symptoms men should never--ever--ignore no matter how great their tendency to deny anything is wrong and hope that will make it go away.

The five potentially life-threatening symptoms men should never ignore:

1. Chest pain
WHAT? Men ignore chest pain? Apparently it happens all the time. They chalk it up to indigestion or stress. "I tell my medical students that the most common symptom of a heart attack is chest pain, and the second most common one is denial," Simon quipped to CNN. If you experience chest pain of any kind, including tightness or shortness of breath, seek medical attention immediately.

2. A big belly
A big belly is a sign of danger. Not only does it mean a man has low levels of testosterone, but also it indicates a higher risk for type 2 diabetes and coronary artery disease. Instead of going on a diet or admitting they have gotten too big for their britches, they deny they have a big belly by just lowering their belts.

3. An unenthusiastic penis
While many cases of impotence are indeed psychological, impotence can also be a symptom of cardiovascular disease. "The penis is the dipstick of the body's health," Dr. Harry Fisch, a professor of clinical urology at Columbia University, told CNN. For the penis to function as it should, it needs healthy arteries to supply blood. If the penis isn't getting that blood, the heart and brain might not be getting it either.

4. More frequent urination
Frequent urination can be a symptom of prostatitis, which is an inflammation of the prostate gland. Men, if you're getting up two or three times at night to urinate, call your doctor.

5. Prescription drug addiction
It's possible to become addicted to prescription drugs, such as Vicodin and Oxycontin, and not even realize it. A man can take medication for back pain and then realize several years have gone by and now he can't function without it--even though the back pain is long gone. If that happens, it's time to get help.

--From the Editors at Netscape