Impotence, while not to be taken lightly, isn't a life-threatening condition on its own. Men don't actually need sex to stay alive (no matter what they may tell their wives). But impotence, also known as erectile dysfunction, can in fact portend some deadly health problems.
Dependable erections are not necessarily a sure sign of excellent health, but a penis that won't rise to the occasion is a warning that something may be awry.
In treating men with erectile dysfunction, doctors worry most about heart disease. "Any form of cardiovascular disease is more likely to occur in men who have erectile dysfunction," says Ira Sharlip, MD, a urologist in San Francisco and past president of the Sexual Medicine Society of North America.
Erections depend on healthy blood flow to the penis. During an erection, vessels in the penis become engorged with blood to produce an erection. Many diseases that affect the blood vessels can interfere with blood flow to the penis. Atherosclerosis (hardening of the arteries) and high blood pressure (hypertension) can cause abnormal blood flow to the penis and can affect a man's ability to have an erection.
That's not to say that everyone with heart disease is impotent, or vice versa. "It's not a simple relationship between the two conditions by any means," says Ira Nash, MD, spokesman for the American Heart Association and associate professor of medicine at the Mount Sinai School of Medicine in New York City.
"There are certain cardiovascular drugs that have the potential to induce impotence," he says. For example, medications used to treat high blood pressure can also cause erectile dysfunction. So can other medications, such as those used to treat depression.
All things considered, doctors treating men with erectile dysfunction must always keep in mind that heart disease may be lurking in the background. "I always arrange for them to see a primary care physician or an internist for a cardiac evaluation," Sharlip says.
Running Low on Testosterone
In addition to healthy blood circulation, the male sex hormone testosterone is important for erections and for sex drive. Men with erectile dysfunction may have low testosterone levels.
"Most of us think that one of the measurements one must do when you have a patient with newly diagnosed [erectile dysfunction] is look at testosterone levels," says Glenn Cunningham, MD, spokesman for the Endocrine Society and a professor at Baylor College of Medicine in Houston.
Many things can cause testosterone levels to be low, such as problems with the pituitary gland, which regulates the production of the sex hormone; thyroid abnormalities; liver problems; and abnormalities within the testes themselves. So if you're unable to get an adequate erection, it's possible that something is causing trouble with your body's testosterone production.
Most commonly, however, low testosterone is a result of aging. "[Male sex hormone] deficiency occurs with greater frequency in older-aged men," Cunningham says, but doctors don't know exactly why. "There are theories, but it's not well understood at this point."
If low testosterone is the only cause of a man's erectile dysfunction, it can be treated with testosterone replacement therapy.
Missed Signals
As with all bodily functions, erections depend on signals from the brain that say when to start and when to stop. The inability to get an erection can sometimes result from a problem with the nerves carrying signals from the brain to the penis.
Erectile dysfunction may be a sign of undiagnosed or poorly managed diabetes. People with diabetes who don't keep their blood sugar levels under control can develop nerve damage (neuropathy). Often it's the nerves of the extremities, such as the hands and feet, that are damaged. But the genitals can be affected, too.
According to the National Institute of Diabetes & Digestive & Kidney Diseases, it's estimated that about one-half of all people with diabetes have some kind of neuropathy. It becomes more common in those who are older, overweight, and those with high blood pressure.
Besides diabetes, which is very common in the U.S. today, there are other, somewhat rarer things that affect the nervous system and can in turn cause erectile dysfunction.
"I see a lot of HIV patients that have erectile dysfunction, which is due to neuropathy," Sharlip says. "The virus causes neuropathy, and the antiviral agents that are used for treatment also themselves cause neuropathy."
Multiple sclerosis and spinal cord injuries are diseases of the nervous system that can cause impotence, although impotence is not one of the main symptoms of either disease.
Sometimes men who abuse alcohol and drugs that depress the central nervous system may find themselves unable to achieve erections, too.
About 90% of the time, the cause of erectile dysfunction is physical. But erectile dysfunction can also be caused by psychological problems such as stress or performance anxiety. Men whose erectile dysfunction is mainly a psychological problem are able to get an adequate erection but not when they want to.
The classic test to find out whether the problem is psychological or physical is to measure "nocturnal tumescence." This involves wrapping a strip of paper or tape around the flaccid penis at night. If the strip is broken in the morning, an erection likely occurred during sleep and impotence is most likely a psychological one.
When the problem is psychological, the underlying depression or anxiety is what should be treated.
Lifetime Piling Up
Erectile dysfunction seems to have become the proverbial canary in a coal mine, especially for older men. That's because it can be caused by any combination of various health problems that strike men later in life.
Men who might not otherwise be diagnosed with something potentially fatal may become aware of the problem when they go to the doctor seeking a prescription.
That's one argument doctors may bring up if drug companies ever lobby to make erectile dysfunction drugs available over the counter. Impotence isn't a problem that exists in a vacuum; and although the drugs to treat it appear to be safe for most men, doctors believe they need to keep a close eye on those who are taking them.
Sharlip says he thinks it's dangerous to take your doctor out of the loop by buying Viagra on the Internet, for example. "Internet acquisition of these drugs is the same thing as over-the-counter," he says. "They say there's a physician that's overseeing it, but there's no physician overseeing it very carefully."
