Hope in Dope for “Athletes” with Heart Failure
October 8, 2008
by Julia Hess
Image: Simon Maybaum (Cardiology), Associate Professor and director of the Montefiore Einstein Center for Advanced Cardiac Therapy.
Swimmer Jessica Hardy withdrew from the Beijing Olympics when drug tests revealed clenbuterol in her system. Runner Kara Goucher, with her eye on the 2008 New York City marathon, sleeps in an altitude-simulation tent as part of the training that led to her recent upset of world marathon record-holder Paula Radcliffe. Legal and not, the same doping methods that capture as much public attention as Michael Phelps’ 12,000-calorie-a-day diet may benefit an unlikely class of athlete: those with chronic heart failure.
Simon Maybaum, Associate Professor of Cardiology and medical director of the Montefiore Einstein Center for Advanced Cardiac Therapy, is currently investigating how clenbuterol and altitude training could improve skeletal muscle function, cardiac function, and exercise capacity in patients with chronic heart failure.
Once advised against physical activity due to doctors’ concern that any stress on the heart would exacerbate the disease, many heart failure patients are now encouraged to exercise moderately to delay the disease’s accompanying skeletal muscle atrophy and impaired muscle metabolism. “Improving skeletal muscle function to enhance exercise performance is particularly crucial for these patients,” said Maybaum. “It makes physiological sense—when they feel better, they’ll be able to exercise more effectively, starting an upward spiral.”
Maybaum, a heart failure/transplant specialist who has run the New York City marathon, began examining athletic performance enhancers that might work for his patients. He ruled out anabolic steroids due to their adverse effects including liver tumors and decreased HDL cholesterol, choosing instead clenbuterol, a beta agonist conventionally used for asthma and popular among athletes, models, and horse trainers for its ability to burn fat and increase lean muscle mass. A study led by Emma Birks, a senior lecturer at Imperial College London, had already shown that clenbuterol improved heart muscle recovery in patients with left ventricular assist devices (LVADs). Maybaum ran subsequent trials and found that clenbuterol increased skeletal muscle mass and strength in both LVAD patients and stable patients with chronic heart failure. However, while these patients grew stronger from taking the drug, their endurance did not increase.
Clenbuterol mimics the effect of weightlifting, increasing muscle power by promoting conversion of “slow-twitch” (endurance) muscle fibers to “high-twitch” (strength) fibers. Low endurance training slows this transition, giving muscles more time to build the capacity to extract oxygen and consume amino acids, one of the reasons the drug is abused by athletes. Athletes combine clenbuterol with training to increase both strength and endurance and maximize effect, a combined strategy now being evaluated in Maybaum’s heart failure patients.
Trial participants perform about 25 minutes of circuit training three times a week while taking clenbuterol in a pulsed regimen. In this randomized, placebo-controlled study, the regimen’s effectiveness is measured through changes in peak oxygen consumption, skeletal and heart muscle function, body composition, exercise capacity, and quality of life.
In a forthcoming trial, Maybaum will have patients spend ten 3-to-4-hour sessions in a Hypoxico altitude simulation enclosure (the same kind used by Shalane Flanagan), then examine the effect of this exposure on their exercise performance. Simulated altitude will start at 1500 meters and gradually be increased to a maximum of 2700 meters, slightly above the pressurization of an airplane cabin. Athletes who follow this “live high train low” concept—extended periods of altitude exposure while training at sea level—experience increased blood and tissue oxygenation, higher red blood cell counts, improved ventilation, stronger cardiac muscle performance, and a boost in physical performance in as few as 3-4 weeks. Such physiological changes would be great for heart failure patients, Maybaum believes.
How would these doping methods benefit a cardiologist who hopes to run another marathon? “I never took clenbuterol,” said Maybaum, “But I’ll probably try the tent. Since I moved out of the city I haven’t been able to do all the New York Road Runners races, so I’ll need all the help I can get for 2009.