Written in consultation with Joanna Steinglass MD, Evelyn Attia MD, and Deborah R. Glasofer PhD.
In 1964, a moment in time in which more than half of all deaths in the US were due to cardiovascular disease, President Lyndon B. Johnson proclaimed February to be American Heart Month. In recent years, the month of February has been used to increase awareness about a range of related topics including women’s heart health, signs of a stroke, and “knowing your numbers” as they relate to cardiac health (such as pulse and blood pressure).
Here at the Columbia Center for Eating Disorders, when we think heart health, we cannot help but think of the way in which the heart is adversely, often dangerously, impacted by eating disorder symptoms. Approximately one-third of the deaths of patients with anorexia nervosa are due to cardiac complications. Behaviors to counteract food intake – “purging” – are also known to significantly increase the risk of a range of cardiac problems (as described below) in patients with anorexia nervosa and bulimia nervosa.
Eating Disorder Symptoms and The Heart
Dietary restriction – or “energy deprivation” – and the state of starvation seen in anorexia nervosa has profound consequences on the function and structure of the cardiovascular system.
One sign of a change in heart function is the presence of an abnormal heart rhythm referred to, broadly, as an arrhythmia. At low weight, a commonly seen arrhythmia is bradycardia. This abnormally slow heart rate is defined as fewer than 60 beats per minute. It is thought that a slowed heart rate and hypotension, a low blood pressure, signify the starved body’s attempt to decrease as much as possible how hard the heart has to work to keep the body alive, because resources are so limited.
The heart is a muscle, and muscles need fuel. When the heart is not properly fueled over extended periods of time, it decreases in mass (i.e, gets smaller) and weakens.
More specifically, a worrisome change associated with low weight may be the elimination of muscle mass in the heart’s left ventricle. Responsible for pumping fresh blood throughout the body, the left ventricle is the power chamber of the heart and muscle. Weakening in this region can lead to dizziness and low blood pressure, and can contribute to a less than optimally functioning mitral valve, since the valve is attached to the muscle wall in this area.
Both bradycardia and left ventricular weakness are reversible with improved nutrition and weight restoration.
Significant Weight Loss
Atypical anorexia nervosa is characterized by significant weight loss despite having a weight status that is not significantly low. People with atypical AN are at a lower weight than what their bodies may need and both physiological as well as psychological effects of this decreased weight state are possible. Someone with atypical anorexia nervosa can experience similar cardiac effects to those seen at objectively low weight, including a decreased heart size and slowed heart rate. These cardiac effects may be reversed with weight restoration to healthier weight for the affected person and ongoing adequate nutrition.
Purging refers to a range of behaviors that aim to reverse the effects of food intake or compensate for a subjectively or objectively large amount of ingested food. The most common form of purging behavior is self-induced vomiting. Misuse of laxatives, diuretic medications, or other diet agents is another common purging strategy.
Vomiting, laxative and diuretic medications contribute to dehydration and loss of crucial electrolytes in the body such as potassium and sodium, and these changes, in turn, can be dangerous for heart function. Electrolytes are essentially ions that all muscles, including the heart, use to function. If these ions are not present in sufficient amounts or in appropriate ratio to one another, the heart’s electrical activity may be negatively affected.
Electrical activity is critical for the heart to signal contractions. When the conduct of electrical activity is disrupted, it can keep the heart muscle from contracting when it is supposed to. This can lead to problems with blood flow, or to the heart stopping completely.
Dehydration as a result of repeated episodes of purging can result in an unusually high heart rate, termed tachycardia, low blood pressure, or rapid changes in blood pressure.
Electrolytes and the heart’s electrical activity will stabilize and normalize with maintained discontinuation of purging in tandem with adequate nutrition.
Exercise demands a lot from your heart – it has to speed up its contractions in order to keep up with the oxygen needs of the body. As described above, malnourishment can lead to loss of heart muscle. This can lead to less flexibility of the heart, making it harder for it to keep up with the demands being put on it.
Heart Health Assessment
Electrolytes are typically monitored via blood tests. Pulse (heart rate) and blood pressure can be tracked by physical exam by a clinician or self-monitored.
In addition to obtaining heart rate and blood pressure, it is recommended that the cardiac function of individuals with eating disorders is monitored by electrocardiogram (ECG or EKG).
An EKG uses the electrical pulses from the heart to create a tracing that provides feedback about the heart’s rate, rhythm, and conduction. It also yields information about whether there may be a part of the heart muscle that is not functioning normally.
One of the most common – and most dangerous – disruptions seen in anorexia nervosa is a prolongation of one part of the usual heart beat called the QT interval. This subtle slowing of the heart’s conduction is thought to indicate a dangerous vulnerability to other rhythm problems, and even sudden death. A significant prolongation of the QT interval in someone with anorexia nervosa may lead to further evaluation and monitoring, and should always indicate that nutritional rehabilitation is urgently needed.
A Word on “Knowing Your Numbers”
The American Heart Association’s “Know Your Numbers” initiative encourages adults to undergo routine physician screening to stay aware of cholesterol, blood pressure, and body weight.
For individuals with eating disorders, numbers may be misunderstood.
Individuals with anorexia nervosa have some paradoxical findings that are tricky to understand. For example, some underweight individuals with anorexia nervosa have high cholesterol levels despite their low weight and extremely limited consumption of dietary fat. This is thought to be due to poor liver function, or abnormal hormone levels (as normal estrogen levels help keep cholesterol levels relatively low in most women). For underweight individuals, the route to normalizing cholesterol actually involves eating a normal fat diet (i.e., 30%) and increasing weight to normal levels, optimally with resumption of menstrual activity.
Blood pressure is commonly low, due to dehydration in bulimia nervosa, or to low weight and a general slowing of metabolic function in anorexia nervosa. The phenomenon of dropping one’s blood pressure further with change in position from lying down or sitting to standing, also called orthostatic hypotension, is common with dehydration, and is therefore a worry in eating disorders where adequate fluid is not consumed or fluids are regularly lost due to vomiting or laxative use. Orthostatic hypotension is particularly worrisome because it can lead to dizziness and loss of consciousness.
The Heart of the Matter
The heartbreaking reality is that among the many medical complications that arise in the setting of an eating disorder, cardiac problems stand out because they are both incredibly common and very dangerous. That said, the cardiovascular consequences described above will in most cases normalize with improvements in eating, discontinuation of purging behaviors, and, in the case of anorexia nervosa and atypical anorexia nervosa, return to a healthy weight range. This heartens our Team, and we hope it will continue to inspire you too.