What causes ED?
Erectile dysfunction has many underlying physical and psychological causes, most of which are treatable, and is not an inevitable consequence of aging. Getting and keeping an erection requires a complex chain of events. To produce an erection, your blood flow, testosterone, nervous system, and frame of mind must all work together. If something goes wrong with any link in the chain, ED can result.

High blood pressure, diabetes, dyslipidemia and depression are examples of common medical conditions that can cause ED. Medications to treat these disorders can also cause ED, as can other chronic illnesses and side effects from some surgery, particularly prostate surgery.

Underlying conditions associated with erectile dysfunction include the following:

Vascular Disease or Blood Flow Problems
Blood flow problems can be caused by blockages in the blood vessels inside the penis or in an artery that carries blood to the penis. If too little blood flows into the penis, you won't get erections. Arteriosclerosis, the hardening and narrowing of the arteries, causes a reduction in blood flow throughout the body and can lead to ED. It is associated with age and accounts for 50 to 60 percent of ED in men over 60.

Long distance bike riding on a standard bike seat could also damage blood vessels. Other low blood flow causes can include diabetes, smoking, medications and radiation treatment to the prostate or pelvis.

Diabetes
High blood sugar associated with diabetes can damage small blood vessels and nerves throughout the body, which can impair nerve impulses and blood flow necessary for erection. About 60 percent of men with diabetes experience some sexual dysfunction. Patients who have had pelvic surgery, such as prostatectomy or colorectal surgery, can have ED as a result of nerve damage as well.

Hormone Imbalances
Hormone disorders account for 5 percent of the cases of ED. Testosterone deficiency can result in a loss of libido (sexual desire) and loss of erection. Among other conditions, an excess of the hormone prolactin, caused by a pituitary gland tumor, reduces levels of testosterone. Hormone imbalances can also result from kidney or liver disease.

Drugs
Some commonly prescribed medications can contribute to ED, including drugs for high blood pressure, heart medications, antidepressants, and sedatives. A number of over-the-counter medications also can lead to ED. Long-term use of alcohol and illicit drugs may affect the vascular and nervous systems and are associated with erectile dysfunction.

Pelvic Trauma, Surgery
Spinal cord injuries, brain injuries, and stroke can cause ED. Other nerve disorders such as Multiple Sclerosis, Parkinson's and Alzheimer's disease may also result in ED. Trauma to the pelvic region or spinal cord can damage veins and nerves needed to achieve and maintain erection.

Peyronie's Diseanse
This is a rare inflammatory condition that causes scarring of erectile tissue. The scarring produces curving of the penis that can impede sexual function and cause painful erections.

Venous Leak
When the veins in the penis are not able to prevent the blood from leaving the penis during erection, erection cannot be maintained. A Venous leak can be an outcome of injury, disease, or damage to the veins in the penis.

Psychological Conditions
Stress, guilt, worry and anxiety can all contribute to loss of libido and erectile dysfunction. When a man experiences loss of erection, he begins to worry that it will happen again. This concern can create anxiety associated with performance and could lead to chronic problems during sex. A cycle is created and if this cycle is not broken, it can result in chronic impotence.

Nerve Problems
Spinal cord damage, uncontrolled diabetes or surgery on the rectum, prostate or bladder, can all cause damage to the nervous system. An injury along the path prevents the signals from getting through.