Physical:

• When older, it takes longer before the penis gets stiff and the man needs to be sexually stimulated for longer.
• Anomalies in the vessels, for example due to heart and vascular diseases like arteriosclerosis and high blood pressure.
• Surgery of the prostate.
• Diseases and medication for heart and vascular diseases, diabetes mellitus, multiple sclerosis and Parkinson's disease can be a cause. Medicines for depression and high blood pressure may cause erection problems (see also other question).
• Smoking, drugs and alcohol dependence.
• Anomalies of the penis.
• Hormonal anomalies.

It is important to know whether the body functions well. When an erection is possible: in the morning, while sleeping or when masturbating then physical problems can be excluded.

Erection problems are often a symptom of some other illness. Thus, if a man starts having erection problems, he should always get a general medical examination.