News at Mason
Lung Disease Patients Benefit from Cardio Exercise, Study Finds
January 27, 2012
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 new Mason research.
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 makes a simple trip to the grocery store seem like an arduous trek, according to Randall Keyser, associate professor in Mason’s Department of Rehabilitation Science in the College of Health and Human Services.
Keyser wanted to test 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. 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 says.
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. When looking at preliminary, interim results, the improvement just jumped off the page at us.”
Dubbed the NIH Exercise Therapy for Advanced Lung Disease Trial (HEALD), it’s one of the first studies to indicate such an improvement, he says.
“The muscles seem to be improving their ability to extract oxygen from the blood and use it,” says Keyser. “We haven’t 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.”
Keyser’s ongoing study is in its third year and could go nationwide by the fall.
A Serious but Rare Disease
Pulmonary hypertension is a serious but rare disease with a dismal survival rate. About three to five people for every 100,000 Americans are affected. Nearly 40 percent die in the first three years of diagnosis. There are some 280,000 hospitalizations a year due to the disease, Keyser says.
“People who do survive really become debilitated because they have shortness of breath and they get fatigued,” says Keyser. “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.”
Medications help some but not enough, Keyser says. Physicians typically didn’t recommend physical exercise because they were concerned about putting too much stress on the heart. Some studies indicate that may not be such a worry, he says.
Improvement on the six-minute walk test was 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.”
Measurable Improvement in Physical Performance
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 because we have not yet measured it, but those are the potential implications. What we do know is that they are able to perform better physically.”
Keyser is working with Leighton Chan, investigator and chief of rehabilitation medicine at the NIH Clinical Center, and Steven Nathan, director of the Advanced Lung Disease and Transplant Program at Inova Fairfax Hospital. The team recently won the Alfred Soffer Research Award from the American College of Chest Physicians for this work.
Participants received a slew of tests before they entered the study. In addition to the six-minute walk test, they were given a medical checkup and answered questions about their quality of life. 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 were also measured.
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,” says Keyser. “That’s not saying it doesn’t add value, it’s just that our data is 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.
So far, HEALD has 21 subjects. The goal is 80. “It’s a rare disease, so recruitment is slow,” says Keyser.
Keyser and his colleagues plan to work with the University of California, Los Angeles; Duke University; and Harvard University as the study enters its third phase and goes nationwide to a total of 10 centers. The nationwide study would follow the protocols established by Keyser.
Keyser stresses that despite the encouraging findings, pulmonary hypertension sufferers shouldn’t decide to start exercising without medical oversight. “We haven’t gotten to the point where we can say this is something you can do on your own,” he says. “Maybe someday we’ll get there, but patients need medical supervision because of the seriousness of the disease.”