Embargoed Until September l9, 2000
Contact: Donna Krupa703.527.73457Cell: 703.967.2751[email protected]
PATIENTS WITH CONGESTIVE HEART FAILURE RESPOND FAVORABLY TO EXERCISE TRAINING
In spite of the fatigue and shortness of breath associated with congestive heart failure, CHF patients respond favorably to exercise training; results being presented at a meeting on exercise and physiology by international scientists during Olympics
Portland, ME -- One of the hallmark symptoms of congestive heart failure (CHF) is a reduced tolerance for exercise that is associated with the early onset of fatigue and shortness of breath. Research indicates, however, that even patients with CHF respond favorably to exercise training, says Timothy R. McConnell, Ph.D. Dr. McConnell, of the Section of Cardiology, Geisinger Health System, in Danville, PA, will present his research findings at the American Physiological Society's intersociety meeting, "The Integrative Biology of Exercise," being held September 20-23, 2000 in Portland, ME.
Background: Over 400,000 new cases of Congestive Heart Failure (CHF) are diagnosed each year. Currently, some five million Americans are affected. CHF is more common in older adults but can affect anyone at any age. Heart failure occurs when the heart loses its ability to squeeze blood and the blood gets pushed back into the lungs and the extremities, making daily tasks difficult. Individuals who suffer from congestive heart failure experience exertion-induced shortness of breath because the work of breathing is increased during exercise, respiratory muscle strength and endurance tends to be reduced, and muscles use significant amounts of oxygen with the demand for oxygen increasing during exercise and physical activity.
Methodology: To study the effects of exercise on CHF patients, Dr. McConnell and his colleagues enrolled 31 patients with CHF. Seven of these patients eventually were excluded from the study for various reasons, including cardiac arrest during exercise training, orthopedic limitations, and ventricular ectopy induced by exercise. The remaining 24 subjects participated in a 12-week supervised exercise program that met three times each week. All patients performed a cycle ergometer test to determine their peak exercise capacity and a breathing test to determine respiratory muscle endurance. Heart rate, minute ventilation (Ve), carbon dioxide production (VCO2), and oxygen consumption (VO2) were reported throughout the test.
Results: The results of the study indicated that exercise capacity significantly increased as a result of the exercise training by all measures used--oxygen consumption, ventilatory threshold, caloric expenditure during exercise class, and peak power output.
Improved exercise capacity may enable CHF patients to increase their walking speed from a "slow walking pace" to a more normal pace that is consistent with healthy individuals of the same age. This subtle change may ease the psychological burden of having to take breaks and "holding everyone else back."
Additionally, respiratory muscle endurance also improved as a result of exercise training even though they were still lower than normal, and study participants reported that the perception of effort of breathing during exercise was lower as well.
These changes are important for patients with heart failure, according to McConnell, because they permit the patients to perform their normal activities of daily living with less effort and less perception of effort. As a result, patients do not need to stop and rest as often, are not as tired at the end of the day, and feel less of a burden to others.
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Physiology research in exercise has been responsible for demonstrating that women are physiologically capable of running the marathon without the event being detrimental to their health and well being; the necessity of competing in a hydrated state, seeking frequent fluid replacement during endurance events; being acclimatized to heat before competition; scheduling competition in the early or late hours of the day; and providing fluids that contain a fixed concentration of glucose during the long distance events; the advantages to athletes -- particularly swimmers -- of tapering in their training before competition; the importance of the specificity concept in athletic training schedules and the acceptance by coaches of team sports (such as basketball and volleyball) that specific power and strength training principles must be followed to enhance performance.
The American Physiological Society is devoted to fostering scientific research, education, and the dissemination of scientific information. By providing a spectrum of physiological information, the Society plays a significant role in the progress of science and the advancement of knowledge.
Editor's Note: For further information or to schedule an interview with Dr. McConnell, contact Donna Krupa at 703.527.7357; cell: 703.967.2751; or at [email protected]; or visit the APS website at www.faseb.org/aps.
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