What Happens During a Heart Attack?

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Leslie Minton

What Happens During a Heart Attack?

During a heart attack, the heart can’t get enough oxygen to keep beating and to supply blood to the rest of the body.

In the United States, someone has a heart attack every 40 seconds. Because heart attacks are so common, it’s important to understand exactly what causes them. And we might understand this best if we take a look at the heart from the inside.

Illustration of red blood cells in a blood vessel

Did you know the heart can pump nearly 2,000 gallons of blood every day? This illustration shows blood cells traveling through a blood vessel.

Imagine you are a tiny, round, and flat red blood cell. It is your job to carry oxygen through the entire human body. You take oxygen from a human’s lungs, and zoom through arteries to drop off that oxygen in muscles all around the body. Heart muscles are very important muscles that keep blood moving through the body. Heart muscles use oxygen to make energy so they can keep beating.

Blood can only get to the heart muscles through coronary arteries. This means coronary arteries are very important paths that need to stay open to keep the heart beating. But sometimes there are blockages along the way to the heart. These blockages are made of fatty deposits called plaque. When too much plaque builds up, you and other red blood cells can’t get by to deliver oxygen. Soon, so many cells pile up that it forms a blood clot.


The heart beats up to 100,000 times a day. To do this, it needs a steady supply of oxygen, which it can only get through the coronary arteries. Click for more detail.

If you become a clot and stop moving, the heart won’t get the oxygen it needs to keep beating. And when a heart loses oxygen, it can’t pump enough blood to power the rest of the body. This can throw off the heart’s normal rhythm, and the heart can sometimes stop beating completely. This is called a heart attack.

Heart attacks can feel different to different people. Some experience chest pain, shortness of breath or pain in their left arm. Others feel nauseous, weak or tired. A human experiencing these symptoms should always see a doctor. Eating a heart-healthy diet low in sugar and full of whole grains, vegetables and lean proteins will help red blood cells do their job. Exercising helps, too.

Additional images via Wikimedia Commons. Red kangaroo image by Adamantios. Front view of heart by BruceBlaus.

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Bibliographic details:

  • Article: What Happens During a Heart Attack?
  • Author(s): Dr. Biology
  • Publisher: Arizona State University School of Life Sciences Ask A Biologist
  • Site name: ASU - Ask A Biologist
  • Date published: February 14, 2018
  • Date accessed: June 12, 2024
  • Link: https://askabiologist.asu.edu/questions/heart-attacks

APA Style

Dr. Biology. (2018, February 14). What Happens During a Heart Attack?. ASU - Ask A Biologist. Retrieved June 12, 2024 from https://askabiologist.asu.edu/questions/heart-attacks

American Psychological Association. For more info, see http://owl.english.purdue.edu/owl/resource/560/10/

Chicago Manual of Style

Dr. Biology. "What Happens During a Heart Attack?". ASU - Ask A Biologist. 14 February, 2018. https://askabiologist.asu.edu/questions/heart-attacks

MLA 2017 Style

Dr. Biology. "What Happens During a Heart Attack?". ASU - Ask A Biologist. 14 Feb 2018. ASU - Ask A Biologist, Web. 12 Jun 2024. https://askabiologist.asu.edu/questions/heart-attacks

Modern Language Association, 7th Ed. For more info, see http://owl.english.purdue.edu/owl/resource/747/08/
A resting kangaroo, image links to Top Question page

Humans aren't the only animals that get heart attacks. Kangaroos and other animals can also suffer from sudden cardiac arrest.

See more top questions

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