Part of getting an erection involves blood vessels in the penis relaxing and widening so that the penis can fill with blood. Any condition that makes your blood vessels less likely to relax and widen can make getting an erection difficult, no matter how much you may want it to happen.
Hardening of the arteries
One condition that impairs blood flow to the penis is hardening of the arteries (atherosclerosis), where fat builds up on the inside of blood vessels, making them narrow and more rigid.
Conditions affecting the heart and blood vessels
Other conditions affecting the heart and blood vessels can also indicate that the blood vessels in your body are not as healthy as they once were and can increase the likelihood of erection problems. These include:
high blood pressure (hypertension)
heart disease
some types of stroke
previous heart attack
high cholesterol: Men with high cholesterol levels have an 80% increased risk of erection problems.
Medical conditions that affect the nerves
For the blood vessels of the penis to relax, a healthy nerve supply is needed. Therefore, conditions that affect the nerves also affect your erections.
Spinal cord injury and conditions such as Parkinson’s disease or multiple sclerosis could potentially cause erection problems.