Why You're Most Likely to Have a Heart Attack in the Morning

Medically Reviewed By William C. Lloyd III, MD, FACS
Was this helpful?
Senior man with chest pain

Did you know people are more likely to have a heart attack in the morning than any other time of day? This may seem to run counter to what we think about heart attacks. We often hear about them occurring in the middle of a crisis, during intense physical activity, or when we are seriously stressed. But what is it about the morning that actually makes it a more likely time of day for a heart attack?

Causes of Heart Attacks

The most common cause of a heart attack is coronary heart disease (CHD). Plaque builds up over time along the walls of the artery, causing the blood vessel to narrow. Eventually, the narrowing becomes severe enough to reduce the blood flow to the heart or block it altogether. A blood clot traveling through the blood vessels can also cause a heart attack by plugging the artery and blocking the blood flow.

Why Mornings Are Riskier for Heart Attacks

Researchers have some theories they’re working on to explain why people may be more likely to have a heart attack in the morning than any other time of day. One theory looks at a protein in your blood called PA1, which prevents clots from dissolving. The results of a small study showed that healthy study participants had higher levels of PA1 around 6:30 a.m., after they woke up. This higher level of PA1 increases the risk of clot formation in a blood vessel, blocking blood flow to the heart. As the morning went on, the levels for those in the study dropped back to normal ranges.

Other researchers think early morning heart attacks could have other causes, such as an elevated amount of stress hormones. As you wake up, your body releases stress hormones to get your body up and going for the day. In addition, your body tends to be dehydrated by the time you wake up and for some people, this combination of added stress hormones plus dehydration may be enough to trigger a heart attack.

Aside from the increased risk of heart attacks in the morning, researchers have also found that morning heart attacks may cause more damage to the heart than those that occur during any other time of day. No matter the hour, it’s important to seek immediate treatment for symptoms of heart attack if you or anyone else experiences them.

Heart Attack Symptoms

The signs and symptoms of a heart attack can vary, especially between men and women. Women often report subtler signs, first believing they were caused by something else, such as stomach upset or stress. For anyone, the symptoms of a heart attack may come on strongly and suddenly, or they may come on gradually. The most common ones include:

If you experience any of these signs and symptoms, you must act immediately. Call 911 or your local emergency number right away, or have someone else drive you to the closest emergency room.

Heart Attack Prevention

Not all heart attacks can be prevented, but you can lower your risk of having one. Here are some ways:

  • Go for regular check-ups, particularly if you have been diagnosed with heart disease or you have a sibling, parent or grandparent who has heart disease or has had a heart attack.

  • Follow your treatment plan if you do have heart disease. Take your medication as prescribed and go for regular testing.

  • Manage any chronic diseases, such as diabetes.

  • Eat a heart-healthy diet, and lose weight if necessary.

  • Exercise regularly.

  • Reduce the amount of stress in your life as much as possible.

  • Avoid illegal drugs, as they can cause coronary artery spasms.

  • Ask your doctor if you should take aspirin regularly or take aspirin as soon as you experience any signs of a heart attack.

We don’t always feel our best first thing in the morning as we struggle to wake up and face the day. But if you experience any signs or symptoms of a heart attack, these should be taken seriously. Your odds of surviving increase dramatically with quick recognition and rapid treatment.

Was this helpful?
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 2
View All Heart Attack Articles
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Heart Disease: Scope and Impact. The Heart Foundation. http://www.theheartfoundation.org/heart-disease-facts/heart-disease-statistics/
  2. What Causes a Heart Attack? National Heart, Lung, and Blood Institute. Part of the National Institutes of Health. https://www.nhlbi.nih.gov/health/health-topics/topics/heartattack/causes
  3. Scheer FAJL, Shea SA. Human circadian system causes a morning peak in prothrombotic plasminogen activator inhibitor-1 (PAI-1) independent of the sleep/wake cycle. Blood. 2014;123(4):590-593. doi:10.1182/blood-2013-07-517060. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3901072/
  4. Surprising heart attack and stroke triggers—from waking up to volcanoes. Harvard Health Publications. Harvard Medical School. http://www.health.harvard.edu/press_releases/heart-attack-triggers
  5. Heart attack. Mayo Clinic. http://www.mayoclinic.org/diseases-conditions/heart-attack/basics/symptoms/con-20019520
  6. Suárez-Barrientos A, López-Romero P, Vivas D, Castro-Ferreira F, Núñez-Gil I, Franco E,  et al. Circadian variations of infarct size in acute myocardial infarction. Heart 2011;97:970-976 doi:10.1136/hrt.2010.212621