If you’re wondering how eating disorders affect the heart, you’re asking an important question. Eating disorders, including anorexia nervosa, bulimia nervosa, and other restrictive or purging behaviors, can change the way the heart works both immediately and long-term.
Two pathways explain most of the risk: malnutrition, which weakens cardiac muscle and lowers blood pressure and output, and electrolyte or fluid imbalances from vomiting, laxative or diuretic use, and dehydration, which can disrupt the heart’s electrical system and trigger dangerous arrhythmias.
Some people develop slow heart rates (bradycardia) or low blood pressure from long-standing restriction; others face sudden rhythm problems after severe electrolyte loss or during rapid refeeding.
The good news is that many cardiac effects are detectable and treatable when medical care, nutrition support, and psychiatric treatment are coordinated early. If you notice palpitations, fainting, chest pain, or significant dizziness, seek medical evaluation right away.
How Do Eating Disorders Affect the Heart?
Eating disorders can affect the heart in a few predictable and often avoidable ways. The problems usually come from three things: not eating enough, losing fluids and minerals through purging, and the way the body reacts when you start eating again after a long period of restriction. Those three paths can overlap, so someone who restricts food can still be at risk if they begin purging or are re-fed too quickly.
Not enough food (malnutrition)
When you don’t get enough calories for a long time, your body pulls energy from muscle, and that includes heart muscle. The heart can become smaller and weaker, which makes everyday activities feel tiring and can reduce the heart’s ability to pump blood. Deeply underweight people often have slow heart rates and low blood pressure because the body is conserving energy.
Purging, dehydration, and loss of minerals
Vomiting, laxatives, or diuretics can wash out key minerals like potassium and magnesium. Those minerals help the heart keep a steady beat. When they fall too low, you can get palpitations (a fluttering or pounding feeling), dangerous irregular heartbeats, and in rare cases, sudden heart failure. Long-term purging can also harm the kidneys and exacerbate these problems.
Restarting food too quickly (refeeding)
After prolonged restriction, the body shifts when food returns. That shift can pull minerals into cells and temporarily leave the blood very low in phosphate, potassium, or magnesium. If that happens suddenly, the heart can struggle, which is why refeeding should be done slowly with regular blood tests and medical oversight.
Quick note on rhythms
Some of these problems show up as changes on an electrocardiogram (ECG). Those changes can raise the risk of serious rhythm problems, so heart checks are a routine safety step for people at risk.
Bottom line
Cardiac risks depend on the type of eating behavior and how long it’s gone on, but many heart problems can be detected early and improved with careful medical and nutritional care. If you notice fainting, chest pain, very fast or irregular heartbeats, or extreme dizziness, get medical help right away.
What Symptoms or Warning Signs Should You Watch For?
If you or a loved one has an eating disorder, get immediate medical care for any of the following signs.
- New or noticeable changes in heartbeat, such as very fast, irregular, or unusually slow pulses, can be a red flag.
- Lightheadedness, fainting, or frequent near-fainting suggests inadequate blood flow or an arrhythmia.
- New or worsening shortness of breath with minimal activity, unexplained chest pain or pressure, and persistent, unexplained fatigue all merit urgent evaluation.
- Swelling in the legs, sudden fluid gain after stopping purging, or large shifts in weight during refeeding can indicate fluid or electrolyte problems.
These symptoms often reflect acute electrolyte disturbances or declining cardiac function and typically prompt an ECG, serum electrolyte testing, and a focused cardiac exam. If any of these occur, contact a clinician or emergency services right away.
How Cardiac Risk is Assessed and Managed
We take heart safety seriously and keep the steps straightforward. During intake and treatment, we use routine medical checks and lab work to monitor your body’s health. That includes monitoring vital signs and tracking electrolyte levels and other labs as needed. Nutrition is reintroduced carefully under medical and dietitian guidance, with frequent blood tests to make sure refeeding is progressing safely.
If a medical concern comes up, we coordinate with outside medical providers and hospital partners to get the right care quickly. In our residential setting, people who need closer supervision receive around-the-clock monitoring and support until their labs and overall medical status are stable.
After stabilization, we plan regular follow-up to catch issues early and reduce the likelihood of recurrence.
Getting Care Early Matters
Cardiac complications are one of the most serious medical risks linked to eating disorders, yet many of those risks are detectable and treatable when care is coordinated early.
If you notice warning signs such as fainting, chest pain, palpitations, or rapid weight shifts, contact your healthcare provider or a specialized eating disorder program right away. For help evaluating next steps, reach out to your primary clinician or a program that offers medical monitoring and nutrition support.
Frequently Asked Questions
Can an eating disorder cause permanent heart damage?
Many cardiac changes caused by malnutrition and dehydration improve with sustained nutritional rehabilitation and monitoring, including increases in left ventricular mass and improved blood pressure. However, prolonged, severe malnutrition can lead to lasting structural or functional changes in some people, so earlier treatment lowers the chance of permanent damage. Clinical reviews note that recovery is common but not guaranteed after very long or severe illness.
Why is low potassium so dangerous for the heart?
Potassium helps coordinate the heart’s electrical signals. When potassium falls too low, commonly due to vomiting, laxative use, or diuretic abuse, the heart’s rhythm can become unstable. Hypokalemia can cause weakness, palpitations, and severe arrhythmias that may progress to ventricular fibrillation. That is why prompt medical assessment and replacement of potassium under clinical supervision are essential for anyone with ongoing losses.
Is bradycardia (slow heart rate) always dangerous?
Mild bradycardia may be tolerated, especially during sleep, but very low resting heart rates accompanied by dizziness, fainting, lightheadedness, or low blood pressure need urgent evaluation. Bradycardia is common in restrictive eating disorders such as anorexia nervosa and often improves with nutritional rehabilitation, but severe or symptomatic cases sometimes require inpatient medical stabilization. Clinicians use ECGs and continuous monitoring when rates are dangerously low.
What happens during refeeding that affects the heart?
Refeeding shifts the body from starvation metabolism toward active nutrient use. Insulin release drives phosphate, potassium, and magnesium into cells, which can cause hypophosphatemia and other electrolyte drops. Those shifts reduce cardiac contractility and may lead to heart failure, respiratory failure, or arrhythmias if not managed. Refeeding syndrome is preventable with slow, protocolized nutrition increases, vitamin repletion, and frequent lab monitoring.
When should I seek emergency care?
If you notice any of the following, get medical help right away: crushing chest pain or pressure, fainting (or almost fainting), sudden severe weakness, very fast or wildly irregular heartbeats, or extreme shortness of breath from minimal activity. Signs of severe dehydration, such as very little urine, dizziness, or confusion, also deserve urgent attention. These symptoms can mean serious electrolyte problems or a failing heart and usually require an ECG, blood tests, and quick medical treatment. If you’re unsure, call your healthcare provider now or dial emergency services.