How anorexia nervosa can affect heart rates

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Those who struggle with anorexia nervosa (AN) severely restrict what they eat due to an intense fear of gaining weight and distorted perception of their bodies. Extreme caloric restriction can cause serious health complications, including affecting heart rates, and damaging the heart. But early intervention and effective treatment can help restore health and lead to recovery.

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Heart complications in anorexia nervosa

Severely limiting the amount and types of food a person eats deprives the body of the valuable nutrients and sources of energy it needs to function. The extreme caloric restriction a person with anorexia engages in can harm the body and its organs, especially the heart. 

Cardiovascular complications a person who has AN can experience include: (1,2,3)

  • Dangerously low heart rate (bradycardia) 
  • Precipitously high heart rate (tachycardia)
  • Heart attack
  • Low blood pressure (hypotension)
  • Heart palpitations 
  • Fluid retention in the heart (pericardial effusion)
  • Heart failure

Because diagnosing AN can be elusive, these heart problems can go untreated for years. And because of this, anorexia has the highest mortality rate among all eating disorders (ED). (1) Prolonged weight loss causes cardiac muscle cells to atrophy dangerously. This results in decreased heart wall thickness, which reduces the volume the heart can pump per contraction (low cardiac output), which then results in reduced exercise capacity and excessive fatigue. (3)

Dangerously high and low heart rates 

When the heart rate is persistently low (bradycardic) or high (tachycardic), it becomes more prone to developing an irregular heartbeat, or arrhythmia. Add any electrolyte abnormalities that may result from not getting enough nourishment, and any arrhythmic episode could result in a heart attack, or cardiac arrest. (3)

Research has found bradycardia anorexia in up to 44% of hospitalized patients in one study, and hypotension in 16% of patients in another. (6,7) 

The heart must pump so many times per minute and create a high enough blood pressure to get blood to tissues within the body, including our vital organs. When the heart rate is too low, blood does not circulate throughout the body. Tissues and organs can go without freshly oxygenated blood only for a few seconds before they become oxygen deprived and die. (3)

While low heart rate is an adapted response to prolonged starvation and negative energy balance, those with AN can have episodes of high heart rate as well. This can be from severe iron deficiency (anemia) or because of an infection, which the body is more prone to when it isn’t getting adequate nourishment. 

Things like pneumonia, cellulitis, and appendicitis cause our immune and cardiovascular systems to increase the heart rate. When someone with AN develops a resting high heart rate, a work-up should begin in the hospital setting to investigate for the infectious cause. (5)

Most studies show that cardiac changes ensue when someone has lost approximately 80%-85% of his or her body weight. (3,5) The weakened heart tissue can improve with weight gain, however, this can take months, and usually must be done under the direct supervision of a physician in a hospital setting. When the body lives in this state of severe starvation for a long time, suddenly consuming calories again can cause refeeding syndrome and life threatening electrolyte abnormalities. (1,2,3)

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Within the heart, there are four chambers and four valves. Blood moves through the heart in a one way circuit. The two lower chambers, called the ventricles, have thick muscular walls with enough power and force necessary to expel blood throughout the body. Valves between each chamber prevent blood from regurgitating, or flowing backward.

When the body consumes cardiac muscle cells during prolonged starvation, the overall size of the heart shrinks. The collagen structure of the mitral valve remains the same size despite the decreased heart mass, resulting in mitral valve prolapse (MVP). It produces a clicking sound that can be heard with a stethoscope, and often results in slight amounts of regurgitated blood. This anatomical abnormality can be imaged on a cardiac ultrasound. (3)

One ultrasound study performed on 40 people with AN found MVP in 20% of the sample size (8 people). 8 According to the well renowned Framingham Heart Study, MVP occurs at a rate of 2.4% in the general population. (9)

Someone with AN and MVP will experience chest pain or heart palpitations in the setting of a very low heart rate, or bradycardia anorexia. Regurgitation of blood through the mitral valve, in one study, was shown to be rare, and no cases have been reported to date that required someone undergoing mitral valve surgery. Most everyone can resolve MVP in the setting of AN with slow, incremental, inpatient facilitated weight gain. (4)

Heart failure

Many layers of tissue surround the heart. In the setting of various diseases, sometimes excess pockets of fluid accumulate between these layers. If enough fluid accumulates, it restricts how well the heart can fill with blood and contract. This is called a pericardial effusion. 

In minor cases the person will not feel any symptoms. If the pocket of fluid grows however, a rubbing sound will be heard through a stethoscope, and the person will experience symptoms of fatigue, breathlessness, with concomitant hypotension and tachycardia. (3)

Prolonged starvation causes widespread protein deficiencies in all tissues, most notably the heart. The thyroid can no longer produce enough thyroid hormone. Researchers believe these two factors are what cause those with AN to develop pericardial effusions. (3,10)

Pericardial effusions, electrical disruptions, MVP, blood pressure dysregulation, and protein wasting all contribute to eventual heart failure. If caught in the early stages, heart failure can be reversed with inpatient monitored refeeding. In moderate to severe cases, heart failure is irreversible. (3,9,10)

It is recommended that you speak with your healthcare provider if you have concerns regarding your heart rate. Our team at Within Health can help with the treatment of anorexia nervosa, or any other eating disorder. Learn more about our commitment to compassionate care by calling our team, or reading about our first steps.

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Disclaimer about "overeating": Within Health hesitatingly uses the word "overeating" because it is the term currently associated with this condition in society, however, we believe it inherently overlooks the various psychological aspects of this condition which are often interconnected with internalized diet culture, and a restrictive mindset about food. For the remainder of this piece, we will therefore be putting "overeating" in quotations to recognize that the diagnosis itself pathologizes behavior that is potentially hardwired and adaptive to a restrictive mindset.


  1. Yahalom, M., Spitz, M., Sandler, L., et al. (2013). The Significance of Bradycardia in Anorexia Nervosa. Int J Angiol, 22(02), 83-94. Accessed 28 Jan, 2022. DOI: 10.1055/s-0033-1334138.
  2. Portilla, M.G. (2011). Bradycardia: an important physical finding in anorexia nervosa. J Arkansas Med Soc, 107(10), 206-208. PMID: 21739848.
  3. Mehler, P. Anorexia nervosa in adults and adolescents: Medical complications and their management. UpToDate. Article last updated: 7 April, 2021. Accessed 28 Jan, 2022. 
  4. Mehler P.S., Krantz, M. (2003). Anorexia nervosa medical issues. J Womens Health, 12(4), 331. PMID: 12804340. 
  5. Krantz, M., Mehler, P. (2004). Resting tachycardia, a warning sign in anorexia nervosa: case report. BMC Cardiovasc Disord, 4, 10.
  6. Mehler, P.S., Blalock, D.V., Walden, K., et al. (2018). Int J Eat Disord. 2018;51(4):305. Epub 2018 Feb 8. Accessed on UpToDate 29 Jan 2022. PMID: 29417593
  7. Miller, K. K., Grinspoon, S. K., Ciampa, J., Hier, J., Herzog, D., & Klibanski, A. (2005). Medical findings in outpatients with anorexia nervosa. Archives of internal medicine, 165(5), 561–566.
  8. Olivares, J. L., Vázquez, M., Fleta, J., Moreno, L. A., Pérez-González, J. M., & Bueno, M. (2005). Cardiac findings in adolescents with anorexia nervosa at diagnosis and after weight restoration. European journal of pediatrics, 164(6), 383–386.
  9. Freed, L. A., Levy, D., Levine, R. A., Larson, M. G., Evans, J. C., Fuller, D. L., Lehman, B., & Benjamin, E. J. (1999). Prevalence and clinical outcome of mitral-valve prolapse. The New England journal of medicine, 341(1), 1–7.
  10. Giovinazzo, S., Sukkar, S.G., Rosa, G.M. et al. (2019). Anorexia nervosa and heart disease: a systematic review. Eat Weight Disord 24, 199–207.
  11. Mehler, P. S., Blalock, D. V., Walden, K., Kaur, S., McBride, J., Walsh, K., & Watts, J. (2018). Medical findings in 1,026 consecutive adult inpatient-residential eating disordered patients. The International journal of eating disorders, 51(4), 305–313.


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