Usually when a man is sexually aroused:
1. The brain sends an impulse telling the arteries in the penis to widen.
2. As a result, more blood flows to the penis.
3. When this happens, the penis expands and hardens. This causes an erection.

When a man has ED, the nerves or blood vessels in the penis don't work properly.
This prevents blood from flowing to the penis which can prevent an erection.

Causes of ED
ED is often related to other health issues that can affect the flow of blood to the penis.
No matter what the cause, treatment is usually effective.

Find out why these issues can affect blood flow:

High blood pressure
High blood pressure makes the heart work harder. This puts strain on the blood vessels, which then harden and narrow.
This can prevent blood from getting to the penis which makes it more difficult to get or keep an erection.

More than 65% of men with high blood pressure also have ED.

High cholesterol
High blood cholesterol can clog your arteries. This can slow blood flow to the penis.
As a result, it can affect the quality of your erections.

Having high cholesterol raises your risk of ED by 80%.

Heart disease
Heart disease also is known as coronary artery disease.

For a person with heart disease, blood does not flow as easily throughout the body as it should.
That's because the arteries are clogged or narrowed. This may slow blood from getting to the penis
and prevent a firm erection.

Diabetes
Diabetes is a condition where there is too much sugar, or glucose, in the blood. Over time, high blood sugar levels
can damage nerves and blood vessels like those that produce erections. When this occurs, diabetes often leads to ED.

Up to 85% of men with diabetes have some erection difficulty.

Prostate problems
The prostate is a small gland near your bladder. It is next to the nerves that are needed for erections. That's why certain treatments for prostate problems can lead to ED.

Depression
For men with depression, the cause of ED may be psychological, physical, or both. ED can lower self-esteem and strain your relationship with your partner. And certain medicines that treat depression can cause ED.

Spinal injury
An injury to the spine can affect almost every function in the body. For men with spinal injuries, ED is the most common sexual problem.

Certain medicines
There are many medicines that can cause ED. The most common are:

• Certain medicines that lower blood pressure
• Some heart medicines
• Some cancer medicines
• Certain medicines for depression

Stress
Stress and anxiety can affect your ability to get an erection. However, they often are not the primary cause of ED. It's more likely to be a physical problem.

When a physical problem causes erection difficulty, men become more anxious about sex. This can increase the severity of ED.

Smoking and alcohol
Smoking and drinking too much alcohol can lead to ED. Drinking alcohol can temporarily impair the ability to get an erection. To help avoid symptoms of ED, it's best not to drink large amounts of alcohol before having sex.

If you smoke, you should consider stopping. Smoking can cause cancer, emphysema, chronic obstructive pulmonary disease (COPD), and other illnesses. It also can damage blood vessels. This may prevent blood flow to the penis and can cause ED.