How Erections Work: The Importance of Nerve Function

Key Points

• Nerve function is one part of a complex system that produces erections.
• Some of the most small and fragile nerves in the body are the ones that run to the penis and help create an erection.
• Any nerve damage, including damage that results from diabetes, can contribute to or cause erectile dysfunction.

When we think about how erections work, one piece of the puzzle often gets overlooked: nerve function.

Nerves are only one component of a complex web of systems needed to produce solid and reliable erections. However, the crucial importance of nerve function is often overshadowed by more glamorous topics such as testosterone and blood flow.

We'll dig into what good nerve function means for your erections, some ways it may be impaired and how you can ensure your penis nerves maintain optimal functionality throughout your lifetime.

How do nerves help erections work?

The nervous system is a complex network that extends throughout the body and stems from the core of the central nervous system (CNS). The CNS consists mainly of the brain and spinal column, which act in tandem as the main processing center for the entire system.

Smaller branches, twigs and ever-smaller tendrils extend out to all parts of the body, growing tinier and more delicate. Some of the most diminutive, fragile nerves in the entire body extend into the penis, reaching into the corpus cavernosa, the chambers that fill with blood when an erection occurs.

"The erectile (cavernosal) nerves are responsible for initiating erections," said Scott D. Miller, M.D., the medical director of Wellstar Urology in Atlanta. "When a signal passes through these nerves to the penis, the nerve endings release nitric oxide (NO), which causes the cells in the erectile tissue to produce various chemicals that cause relaxation of smooth muscle lining the microscopic vascular channels. This triggers an increase in arterial blood flow to the penis."

Indeed, the subject of nitric oxide often features prominently in the relentless tidal wave of advertising for products claiming to help with erections. What those ads and manufacturers don't usually talk about, however, is how important healthy nerves are as the bedrock upon which erections are built and how that precious NO is useless without them.

"Without the erectile nerves, natural erections—even using PDE5 inhibitor drugs [such as Viagra]—are not possible," Miller said. "Fortunately, these nerves are well protected from outside harm. They're independent from two other sets of nerves involved in the sexual response—sensory (skin) and climactic."

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How can nerve damage cause erectile dysfunction?

Other types of nerves involved in the male sexual response can affect erectile and sexual function in a variety of ways. One of the most harrowing—albeit rare—involves spinal damage that results in spontaneous erections and even ejaculations without sexual desire, according to a 2010 study.

One man has been documented as having up to 100 unwanted orgasms per day for years following a slipped disc sustained while getting out of his chair.

However, more common nerve injuries can affect erections and sexual function in males due to various parts of the process being controlled by different nervous system actions.

"If, for example, there's damage to the pelvic nerves, like, say, during a prostatectomy, you might have difficulty obtaining the erection, but you can still achieve orgasm and ejaculation," said Katherine Rotker, M.D., a urologist with Yale Medicine in New Haven, Connecticut, who specializes in male infertility and reproductive health.

"Or, if your nerves are injured during a retroperitoneal lymph node dissection, or a triple-A—abdominal aortic aneurysm—repair near the bifurcation of the aorta, then you might have difficulty with ejaculation, or you might have a dry ejaculation, but you can have normal erections," she added.

How does diabetes affect nerve function and erections?

The most common topic of discussion when it comes to nerves and erectile dysfunction (ED) centers around diabetes. A significant percentage of men have surgery-related nerve damage that affects their sexual function. For millions of others, it's poorly controlled blood sugar that can negatively affect these tiny nerves.

In the United States alone, 37.3 million people—about 1 in 10—have diabetes, according to the Centers for Disease Control and Prevention (CDC). Another 96 million, or about one-third of all Americans, have pre-diabetes, about 80 percent of whom don't know they are pre-diabetic.

This is especially bad news for men in terms of erectile function.

"Diabetes, being the classic neuropathy-inducing or nerve-damaging disease, can have a one-two punch on erectile function," Rotker said. "It affects vasculogenic causes—it affects our blood vessels and makes blood supply more difficult—but it also classically affects those small nerves, those end nerves. This is why long-term diabetics can get neuropathy in the hands and feet, and it can also affect the ability to get and keep an erection."

With poorly controlled blood sugar and potential diabetes ensuing, not only do you get nerve damage, you also get reduced blood flow to the penis. That all-important NO we were just talking about? Yeah, it's also affected.

"Diabetes can contribute to the deterioration of any nerve, and the cavernosal nerves are no exception," Miller said. "Also, diabetic men have a significant decrease in nitric oxide production at these nerve endings."

The takeaways

Advances in nerve-sparing prostatectomy procedures can help most men avoid the worst erection-damaging nerve issues in that regard. The likelihood of another surgical procedure or some wild spinal accident damaging the nerves of your penis is very low.

However, millions of men are at risk of diabetic neuropathy, or nerve damage due to poorly controlled blood sugar. Good erections are worth a doctor visit and a quick blood draw to test for blood sugar levels, especially when you consider that once those tiny, delicate nerves are damaged, they're not coming back.

Remember, too, that you have a lot of power in your hands. A healthy diet with lots of natural, whole foods and a solid exercise program can go a long way toward maintaining your overall health—including your sexual health.