Erectile dysfunction (ED) is the inability to get or keep an erection firm enough to have sexual intercourse. It’s also sometimes referred to as impotence. Occasional ED isn’t uncommon. Many men experience it during times of stress. Frequent ED can be a sign of health problems that need treatment. It can also be a sign of emotional or relationship difficulties that may need to be addressed by a professional.
An erection is the result of increased blood flow into your penis. Blood flow is usually stimulated by either sexual thoughts or direct contact with your penis. When a man becomes sexually excited, muscles in their penis relax. This relaxation allows for increased blood flow through the penile arteries. This blood fills two chambers inside the penis called the corpora cavernosa. As the chambers fill with blood, the penis grows rigid. Erection ends when the muscles contract and the accumulated blood can flow out through the penile veins. ED can occur because of problems at any stage of the erection process. For example, the penile arteries may be too damaged to open properly and allow blood in.