Anorexia nervosa is a serious eating disorder characterized by an intense fear of gaining weight and a distorted perception of one’s body, often leading individuals to severely restrict their food intake. This condition can have widespread effects on nearly every organ system, including the cardiovascular system. While many people might associate anorexia with a weakened, slow heart, the relationship between anorexia and blood pressure is complex. Low blood pressure is more common, but specific circumstances can lead to high blood pressure.
Typical Cardiovascular Responses to Anorexia
The body’s response to severe calorie restriction in anorexia nervosa typically involves physiological adaptations aimed at conserving energy. A common cardiovascular response is low blood pressure (hypotension) and a slowed heart rate (bradycardia). Bradycardia is particularly prevalent, affecting up to 95% of individuals, with some patients exhibiting heart rates as low as 20 beats per minute.
These changes reflect the body entering a state of energy conservation, similar to hibernation. The metabolic rate decreases, reducing the body’s energy needs. This leads to a decrease in cardiac output, the amount of blood the heart pumps per minute. The primary mechanism behind this slowed heart rate is an increase in vagal tone, part of the parasympathetic nervous system, alongside a downregulation of the sympathetic nervous system. These adaptive responses help the body cope with prolonged insufficient nutritional intake.
Circumstances Leading to Elevated Blood Pressure
While hypotension is a hallmark of anorexia nervosa, certain situations can lead to elevated blood pressure. One significant factor is refeeding syndrome, a potentially dangerous condition that can occur when severely malnourished individuals begin to receive nutrition after a period of starvation. Rapid refeeding can cause sudden shifts in fluid and electrolyte levels, such as phosphorus, potassium, and magnesium, which can strain the cardiovascular system. These metabolic changes can sometimes contribute to fluid retention and an increase in blood pressure.
Renal dysfunction, or kidney problems, can also play a role. Prolonged malnutrition and dehydration can impair kidney function, leading to the kidneys retaining more fluid and sodium. This increased fluid volume in the body can directly contribute to higher blood pressure readings. Physiological stress, including anxiety and the body’s “fight or flight” response, may also contribute to temporary or sustained increases in blood pressure in some individuals.
Additionally, pre-existing medical conditions not directly caused by anorexia, such as essential hypertension or kidney disease, can complicate the clinical picture. Certain medications prescribed for co-occurring mental health conditions or other health issues in individuals with anorexia might also have side effects that include elevated blood pressure. High blood pressure is not the typical presentation, but it represents a serious complication that requires careful monitoring during treatment and recovery.
Broader Cardiovascular Complications
Beyond blood pressure fluctuations, anorexia nervosa can inflict a range of other cardiovascular complications due to the profound impact of malnutrition on the heart and circulatory system. One such issue is cardiac muscle atrophy, where the heart muscle can shrink and weaken. This reduction in heart mass can impair its ability to pump blood effectively. Studies have shown a significant reduction in left ventricular mass in individuals with anorexia.
Electrolyte imbalances are another serious concern, frequently leading to arrhythmias (irregular heartbeats). Essential minerals like potassium, magnesium, sodium, and calcium are crucial for proper heart function and electrical signaling. When these are depleted due to restrictive eating or purging behaviors, the heart’s electrical system can become unstable, increasing the risk of life-threatening arrhythmias.
Other structural changes can also occur, including alterations in the size of heart chambers and, in some cases, mitral valve prolapse. Fluid can also accumulate around the heart in pericardial effusion, which can restrict the heart’s ability to fill and pump efficiently. The cumulative strain from these various complications can weaken the heart to the point of heart failure, where it can no longer adequately supply blood and oxygen to the body’s organs and tissues. These widespread cardiovascular issues underscore the severe systemic impact of anorexia nervosa.