Lung Disease Patients Benefit from Cardio Exercise, Study Finds
By Michele McDonald
A mere three times a week on a treadmill can give patients with a debilitating and deadly lung disease a renewed spring in their step, according to a new Mason-National Institutes of Health (NIH) research collaboration.
Leighton Chan, MD, MPH, a tenured investigator and chief of rehabilitation medicine at the NIH Clinical Center; Steven Nathan, MD, director of the Advanced Lung Disease and Transplant Program at Inova Fairfax Hospital; and Randall Keyser, PhD, FACSM, associate professor in the Department of Rehabilitation Science at Mason, are collaborating on the project. The group recently received the Alfred Soffer Research Award from the American College of Chest Physicians for its work in this area.
Pulmonary hypertension is a serious but rare disease with a dismal survival rate. About three to five people are affected for every 100,000 people in the United States, with some 280,000 patients hospitalized a year. Nearly 40 percent die within the first three years of diagnosis.
“People who do survive really become debilitated because they have shortness of breath and they get fatigued,” Keyser says. “It’s very difficult to do the day-to-day activities of living. It’s difficult for them to work, although many of them do.”
According to Keyser, pulmonary hypertension robs the lungs of blood flow and causes stress on the heart because it takes more effort to move blood through the lungs. The disease can make a simple trip to the grocery store seem like an arduous trek.
Medications help some but not enough, Keyser says. Physicians didn’t recommend physical exercise because they were concerned about putting too much stress on the heart, but some studies indicate that may not be such a worry, he says.
“Our group wanted to determine if something as simple as walking on a treadmill three times a week for about 30 to 45 minutes each time could make a difference,” says Keyser. For the study, patients needed to boost their heart rate to a target range of 70 to 80 percent of capacity. “It’s very much what you or I would do for exercise,” he adds.
The results were surprising, even to Keyser.
“That cardio exercise could help was our hypothesis,” he says, “but I didn’t think we would be able to show it so early in our recruitment. When looking at preliminary interim results, the improvement just jumped off the page. Our study is one of the very first to indicate such an improvement.
“The muscles seem to improve their ability to extract oxygen from the blood and use it,” Keyser says. “We may have not actually done very much for the lung itself, but it seems that the muscles are starting to compensate for poor lung function. Instead of having more oxygen delivered to the muscles, the muscles take more oxygen out of the blood.”
The participants’ improvement on a six-minute walk test is key to the study’s success. “The test simply measures how far that person can walk in six minutes,” Keyser says. “We tell them to walk as fast as you can, as far as you can, in six minutes.”
After 10 weeks in the study, patients were able to walk 57 meters, or 187 feet, longer than they did at the study’s start. The number is significant because clinical improvement is measured at 40 meters, Keyser says.
Other studies suggest that after 40 meters, patients could live longer, Keyser says. “We can’t claim any of this as an outcome of our study because we have not yet measured it, but those are the potential implications. What we do know is that patients completing the study are able to perform better physically.”
Participants receive a slew of tests before they enter the study. In addition to the six-minute walk test, they are given a medical check-up and answer questions about their quality of life and how the disease affects them. The ability of the heart and lungs to deliver oxygen to the muscles and the muscles to extract oxygen from the blood and use it to supply energy is also measured.
So far, the randomized clinical trial has 21 subjects; the goal is 80.
“It’s a rare disease so recruitment is slow,” Keyser says.
Participants were divided into two groups. One group received education about their disease twice a week for 10 weeks. The second group had the education but also walked on treadmills three times a week for 10 weeks.
“What we observed is really no effect of the education-only program on our outcome variables,” Keyser says. “That’s not saying it doesn’t add value, it’s just our data are based on a physiological intervention.”
After the 10 weeks, patients received the same medical tests and questionnaires as they did in the beginning. The exercising patients reported a reduction in their symptoms, as well as improvements to emotional, psychological, and physical states.
Keyser’s ongoing study is in its third year, and the group is collaborating on a larger-scale nationwide study, which is currently under consideration and could be approved by the National Heart Lung and Blood Institute by the fall.
As the study enters its next phase, the researchers plan to work with institutions such as UCLA, Duke, and Harvard with a total of six centers participating. The nationwide study, if approved for funding, would follow the protocols established by the Mason-NIH-Inova investigational team.
Despite the encouraging findings, pulmonary hypertension sufferers shouldn’t decide to start exercising without medical oversight, Keyser stresses.
“We haven’t gotten to the point where we can say this is something patients can do on their own,” he says. “Maybe someday we’ll get there, but patients need medical supervision because of the seriousness of the disease.”