Men: What Your Sex Life Says About Your Health

Sex scene #3: More and more often, you can't hold an erection.

It might be: A heart problem (the cardiovascular kind, not the romantic kind)

Say you're a relatively healthy midlife guy, a little overweight, and you start having erectile trouble. Count yourself lucky. It might be your tip-off that you're three to five years away from coronary artery disease, says Mulhall. "Two-thirds of men who have had heart attacks had erectile dysfunction (ED) that predated angina by at least three years," he says. "Men are increasingly being diagnosed with ED due to low blood flow, which increases their chance of heart disease."

What to do: Get your cholesterol checked. It's abnormal in 75 percent of men with ED, Mulhall says. "ED isn't just about having bad sex; it's a window to your vascular health," he says. And before things worsen, start exercising and lose weight.

Sex scene #4: You suddenly can't get it up -- but you were fine last month.

It might be: A blocked artery, especially if your leg mysteriously hurts too

The occasional limp penis is a casualty of naturally decreasing hormone levels as men age and experience changes in relationships, says Adam Tierney, a urologist with Dean Health Systems in Madison, Wisconsin. But what happens when ED comes on suddenly? An unusual but worrisome cause is aortoiliac occlusive disease, or Leriche's syndrome, a narrowing of a heart artery due to blockage.

Hallmarks of Leriche's syndrome: erectile problems that come on suddenly (one week you're fine, and the next you have persistent issues) and are accompanied by pain in the leg (especially the calf) or the buttock, especially when you walk or exercise. People with problems of the nervous system (Parkinson's disease, multiple sclerosis, diabetes) are at higher risk, as are smokers and those with high blood pressure.

What to do: Report this unusual combination of symptoms to your doctor. "It's another kind of blood flow issue," Tierney says.