Malnutrition and the Heart Rate

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Malnutrition has many causes. While lack of affordable food and poverty may cause malnutrition in the United States, 8 million people suffer from some type of eating disorder, which can also cause malnutrition, according to Mississippi College. Lack of appetite in the elderly, anorexia nervosa or complications from gastric bypass surgery cause many cases of malnutrition in developed countries. Obesity can also cause malnutrition if protein intake falls below normal. Conditions like severe heart disease, kidney disease, and short gut syndrome can also cause malnutrition. Malnutrition has potentially fatal effects on the heart.


Malnutrition shrinks the heart muscle just as it shrinks other muscle groups. Both the overall volume of the heart and the muscle mass of the left ventricle, which pumps blood out to the rest of the body, decrease in size. Decreased muscle mass results in a smaller amount of blood pumped out with each heartbeat. Electrolyte imbalances are also common in malnutrition.


Bradycardia, an abnormally slow heart rate, often occurs in malnutrition as the body attempts to conserve energy. As many as 95 percent of patients hospitalized for anorexia have bradycardia, the Ohio State University Medical Center reports. Blood pressure falls as the heart rate slows. Irregular heartbeat, medically termed arrhythmia, commonly occurs in people with malnutrition because of electrolyte imbalances. Potassium plays an important part in the electrical conduction system of the heart, Mississippi College adds. Around one-third of anorexia people have anemia as a result of a decrease in red blood cell volume, OSU notes.


Treatments for malnutrition depend on the cause. Medications to combat depression can help those with psychological eating disorders. Hospitalization and feeding through a tube may be necessary in some cases. Behavior-modification therapy is essential for people whose malnutrition has a psychological cause.


The most serious complication of malnutrition is sudden death from cardiac arrest. A low potassium level leads to irregular heartbeats that culminate in death, MassGeneral Hospital for Children reports. As many as 5 to 10 percent of anorexics die within 10 years of their diagnosis, Mississippi College warns. While up to 10 percent of body weight can be lost without ill effects, loss of 40 percent of total body weight is usually fatal, the Gale Encyclopedia of Medicine cautions.


Malnutrition requires recognition before treatment can begin. Between 5 to 10 percent of all anorexia nervosa patients are males, the Ohio State Medical Center warns — a group not traditionally associated with the disease. Many elderly people with malnutrition go undiagnosed — even though 25 percent of them suffer from it, the Gale Encyclopedia of Medicine reports. Once a person develops an irregular heartbeat, death can occur suddenly.