Erectile dysfunction (impotence) is the inability to get and keep an erection firm enough for sex.

The penis contains two cylindrical, spongelike structures (corpora cavernosa). During sexual arousal, nerve impulses increase blood flow to both of these cylinders. This sudden influx of blood causes an erection by expanding, straightening, and stiffening the penis. Erectile dysfunction occurs when there is no increased blood flow to the penis or if the blood flow is insufficient.

Having erection trouble from time to time isn't necessarily a cause for concern. If erectile dysfunction is an ongoing issue, however, it can cause stress, affect your self-confidence and contribute to relationship problems. Problems getting or keeping an erection can also be a sign of an underlying health condition that needs treatment and a risk factor for heart disease. The cause can be caused by physical or psychological issues,

Symptoms

Erectile dysfunction symptoms might include persistent:

• Trouble getting an erection
• Trouble keeping an erection
• Reduced sexual desire

When to see a doctor

A family doctor is a good place to start when you have erectile problems. See your doctor if:

• You have concerns about your erections or you're experiencing other sexual problems such as premature or delayed ejaculation
• You have diabetes, heart disease, or another known health condition that might be linked to erectile dysfunction
• You have other symptoms along with erectile dysfunction

Physical causes of erectile dysfunction

In many cases, erectile dysfunction is caused by something physical. Common causes include:

• Heart disease
• Clogged blood vessels (atherosclerosis)
• High cholesterol
• High blood pressure
• Diabetes
• Obesity
• Metabolic syndrome -- a condition involving increased blood pressure, high insulin levels, body fat around the waist, and high cholesterol
• Parkinson's disease
• Multiple sclerosis
• Certain prescription medications
• Tobacco use
• Peyronie's disease -- the development of scar tissue inside the penis
• Alcoholism and other forms of substance abuse
• Sleep disorders
• Treatments for prostate cancer or enlarged prostate
• Surgeries or injuries that affect the pelvic area or spinal cord
• Low testosterone

Psychological causes of erectile dysfunction

The brain plays a key role in triggering the series of physical events that cause an erection, starting with feelings of sexual excitement. A number of things can interfere with sexual feelings and cause or worsen erectile dysfunction. These include:

• Depression, anxiety, or other mental health conditions
• Stress
• Relationship problems due to stress, poor communication, or other concerns