What Is Ischemia?

Medically Reviewed by James Beckerman, MD, FACC on June 14, 2021

Food, water, exercise, sleep: Your body needs many different things to keep it going. One of those things happens every time you breathe -- every “in” breath pulls oxygen into your lungs, where it enters your blood. It then travels throughout your body in your blood vessels, veins, and arteries.

Some of those blood vessels are big, like highways. Others are small, like back roads. But if any of them gets stopped up, you have a serious problem called ischemia. This means some part of your body isn’t getting enough blood, so it’s not getting enough oxygen, either. It can happen in your brain, legs, and just about everywhere in between.

You usually get ischemia because of a build-up or blockage in your arteries. What it feels like and how it affects you depends on where you get it. But it can lead to life-threatening problems like a heart attack or stroke.

Why Does It Happen?

One of the main causes of ischemia is atherosclerosis. That’s where plaque collects in your arteries. Plaque is a hard, sticky substance that’s made mostly of fat. It builds up slowly, so you don’t even know it’s there at first. But over time, it can harden and narrow your arteries. This slows your blood flow because your blood has less space to move through. It’s a lot like old plumbing in a house -- when there’s gunk in the pipes, water drains slowly and everything clogs up.

You can also get ischemia because of a blood clot. Plaque itself is a problem. But sometimes, it can bust open and form a clot. This causes a sudden and serious stoppage to your blood flow. A piece of a clot can sometimes break off and cause problems in another part of the body, too.

What Problems Does Ischemia Cause?

A number of them -- and some can be life threatening, depending on where you get it. For example:

  • Heart: This may lead to a heart attack, heartbeat that’s not regular, and heart failure. It can also cause chest pain (doctors call it “angina”), or sudden cardiac death. You may hear it called ischemic heart disease, myocardial ischemia, or cardiac ischemia.
  • Brain: This can cause a stroke.
  • Legs: Doctors call this “critical limb ischemia.” It’s a severe condition you can get with peripheral artery disease (PAD). That’s a condition where you have plaque build-up in the arteries of your leg. It causes intense pain, even when you’re resting. If it’s not treated, you could lose your leg.
  • Intestines: This is called mesenteric ischemia. It can cause a hole in your intestine or part of your intestine to die. It can happen in both the small and large intestines.

Are There Symptoms?

Not always. Some people have silent ischemia in the heart or brain. This is when you have ischemia, but no pain or any other signs or symptoms. It can lead to a heart attack or stroke that seems to come out of the blue.

If you do get symptoms, they vary based on where you have ischemia. If you think you might have it, get medical help right away. Here are areas where ischemia can happen and the symptoms you might experience:



  • Headache that comes on hard and fast, sometimes along with dizziness or throwing up
  • Passing out
  • Problems moving your body (weakness, numbness, or you can’t move your face, arm, or leg on one side of your body)
  • Slurred speech and a hard time understanding others


  • Coldness and weakness in your legs
  • Pain in your feet
  • Severe pain in your legs, even when resting
  • Shiny, smooth skin on your legs and feet
  • Sores that won’t heal


Can I Prevent It?

You can help lower your chances of ischemia by making healthy lifestyle choices. These include:

It’s also helpful to see your doctor for regular checkups. They can check for issues like high blood pressure, high cholesterol, and diabetes. This might help you catch problems early, before you even have symptoms.

Show Sources


American Lung Association: “How Lungs Work.”

KidsHealth: “Heart and Circulatory System.”

Vascular Disease Foundation: “Focus on Ischemia.”

Mayo Clinic: “Myocardial Ischemia,” “Peripheral Artery Disease (PAD),” “Intestinal Ischemia,” “Stroke,” “Stress Management.”

American Heart Association and American Stroke Association: “Ischemic Strokes (Clots).”

American Heart Association: “Silent Ischemia and Ischemic Heart Disease,” “Understanding Your Risks to Prevent a Heart Attack.”

Texas Heart Institute: “Silent Ischemia.”

UC Davis Vascular Center: “Critical Limb Ischemia (CLI).”

NIH, National Heart, Lung, and Blood Institute: “Explore Peripheral Artery Disease.”

American Stroke Association, Stroke Connection: “Healthy People and ‘Silent Strokes.’”

Columbia University Medical Center: “Cerebral Ischemia.”

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