Topic guide · Updated November 8, 2026

Erections and blood flow

An erection is a blood flow event. That’s why erection problems are often one of the earliest signs that something is changing in your arteries.

The short version

  • Erections depend on nitric oxide relaxing the arteries in the penis.
  • Erectile problems often show up 2 to 5 years before heart symptoms.
  • Exercise, pelvic floor training, and fruit-rich diets all have research behind them.

How an erection works

When you’re aroused, nerves release nitric oxide in the penis. The arteries and spongy tissue relax and fill with blood. The pelvic floor muscles then help trap that blood so the erection holds. ED pills work on this same pathway: they make the nitric oxide signal last longer.

The early warning

The arteries feeding the penis are smaller than the ones feeding the heart. One leading explanation, called the artery size hypothesis, is that the same narrowing affects small arteries first. Research reviews find erectile problems often show up about 2 to 5 years before heart disease is diagnosed, and men with ED have roughly 40% higher risk of future heart events.

What the research supports

When to see a doctor

If erection problems are new or getting worse, it’s worth a checkup that includes blood pressure, cholesterol, and blood sugar. It can be an early chance to catch heart disease.

Sources

Educational information, not medical advice. Read our medical disclaimer.

Try one thing

See all