UF Researchers: Heart Patients Who Exercise Have Lower Levels Of Harmful Hormones

November 12, 1996

GAINESVILLE—Rest may not be best for patients diagnosed with chronic heart failure, University of Florida researchers say.

Moderate exercise actually may help counteract the harmful effects of high hormone levels that cause a patient’s failing heart to work too hard, researchers reported Nov. 11 at the American Heart Association’s annual meeting in New Orleans.

Elevated levels of the hormones angiotensin II, aldosterone and vasopressin are hallmarks of heart failure. Initially, these hormones help the body compensate for the syndrome by increasing blood volume and helping the heart maintain adequate blood pressure.

“But when these hormones continue to be released in high levels, they becomes detrimental for the patient,” said Dr. Randy Braith, an assistant professor of exercise physiology and cardiology at UF’s College of Medicine.

The hormones cause patients to retain excessive water and increase the work of the failing heart. High levels are associated with poor long-term prognosis and overall survival, Braith said.

“These hormones increase the work of the heart; they increase what we call vascular resistance or high blood pressure,” he said. “If a patient already has a failing heart, these hormones make that failing heart work even harder. That’s why we say people with high levels of these hormones are more apt to have a negative outcome.”

Heart failure is prevalent: Nearly 500,000 new cases are diagnosed every year in the United States, Braith said. Coronary artery disease is the most common cause of heart failure. Many such patients have had at least one heart attack, causing a portion of the heart muscle to die. The heart’s pumping action becomes less efficient, and eventually it begins to fail.

UF researchers studied patients whose mean age was 61; all had coronary artery disease leading to heart failure. One group of patients exercised and another group of heart failure patients served as a control group that did not exercise.

After four months of cardiovascular exercise — walking on a treadmill at 50 to 70 percent of peak heart rate three days a week — Braith and Dr. Carl J. Pepine, co-director of cardiovascular medicine at UF’s College of Medicine, noted the patients had a 30 percent reduction in these hormones across the board.

“We can’t tell you for a fact there will be fewer cardiac-related problems as a consequence of reducing these hormones, but we’d like to think so,” Braith said. “One thing is for sure: High levels of these hormones and bad outcomes go hand-in-hand.”

Cardiologists began recommending exercise rehabilitation for heart failure patients only recently.

“Exercise was not advised just a few years ago, for fear the risk of exercise was greater than the benefits,” Braith said. “These patients only have 20 to 30 percent of heart function left, and for many years cardiologists believed these patients should not exercise at all.

“Recent evidence suggests they can indeed exercise at low to moderate intensity, and that the benefits include a reversal of many of their heart failure symptoms.”