One of Men’s Health’s top experts, T.E. Holt, M.D., a physician in North Carolina, tells this story about one of his patients:

A man came in, dragged by his daughter because, she explained, he had been steadily losing weight and was covered in big lumps. The lumps had been growing for 2 years, maybe more, she said.

I had no doubt, from the moment I saw him, that this man was dying. He had lumps as big as my fist on his forehead and his back, and as I came closer and moved around him, more came into view. When I pressed deeply into his belly, I felt a solid rock where there should have been yielding space.

It was metastatic sarcoma, a rare cancer of the connective tissue. Four months later, the man was dead.

When it comes to their health, says Dr. Holt, guys are notorious for doing too little, too late. As men, we’re told to play through the pain, tough it out, shake it off, and suck it up. There are a dozen other variations of the same message, and they’re all code for: Ignore your symptoms.

And why not? What doesn’t kill us makes us stronger, right?

Here’s the problem: Things kill us all the time. Even when we're young. In fact, guys between the ages of 20 and 40 are twice as likely to die as women, says Dr. Holt.

Most of us, I'd hope, would call a doctor if we were struck by blinding head pain, suddenly couldn't feel one side of our body, or, frankly, noticed fist-size bumps emerging from our foreheads. But some symptoms aren't so obviously dire. We asked writer Allen St. John to put together a list of surprising symptoms you should never ignore. Why? Because your life may literally be hanging in the balance. Call your doctor immediately if you feel . . .

1. SEVERE BACK PAIN
What it feels like: Similar to the kind of agony you'd expect if you'd tried to bench press an armoire. The usual remedies—heat, rest, OTC painkillers—offer no relief.

What it could be: "If it's not related to exercise, sudden severe back pain can be the sign of an aneurysm," says Sigfried Kra, M.D., an associate professor at the Yale school of medicine. Particularly troubling is an abdominal aneurysm, a dangerous weakening of the aorta just above the kidneys. If it bursts, you’ll die within minutes.

A less threatening possibility: You have a kidney stone, in which case you'll only wish you were dead.

How to fix it: Aneurysms can be treated with blood-pressure medication or surgery to implant a synthetic graft.

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