"It's safe for patients with asthma to exercise regularly," according to lead reviewer Felix S.F. Ram, M.D., of Massey University in New Zealand. "In our study, those who did showed an increased ability to take up oxygen. They improved their ventilation, which led to improved cardiopulmonary fitness. We found no evidence to suggest that regular exercise worsens asthmatic symptoms. There's no reason for people with asthma to avoid regular physical activity."
The systematic review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research.
Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
The review combines results from 13 studies, which together involved 455 participants above age 8 who had asthma. All were randomized controlled trials involving 20- to 30-minute aerobic exercise sessions done two to three times weekly for at least four weeks.
A significant effect occurred with physical training on four measures: maximum ventilation the patient can achieve, maximal oxygen uptake, work capacity and maximum heart rate.
Exercise did not bring about a significant effect in other measures such as expiratory air-flow rate, expiratory volume and days of wheezing.
The researchers found no usable data on bronchodilator drug usage, exercise endurance, walking distance or quality of life.
"Achieving a normal lifestyle are realistic goals for most people with asthma," said Gail Shapiro, M.D., a professor with the University of Washington School of Medicine. "Normal exercise tolerance is an important element of this. People with asthma almost always have some degree of exercise-induced asthma," she said. "Regular exercise will improve muscle efficiency and the amount of work that can be done with a specific effort. It will not take away the airways' reactivity that causes exercise-induced asthma (or EA). However there are good medications that can prevent EA."
The Cochrane researchers noted that subjectively many people with asthma report feeling better then they are fit but that the "physiologic basis of this perception has not been systematically investigated."
Ram called for more randomized clinical trials on the effects of physical training on asthma management. "It's particularly important to measure whether the improved exercise performance that follows physical training translates into improved quality of life," he said.
Ram concluded that clinicians "should encourage patients with asthma to exercise regularly. It improves their cardiopulmonary fitness to the same extent that it does for people without asthma. It's comforting that physical training doesn't have an adverse effect on lung function or wheezing in asthmatic subjects." Ram added that it would be advisable for patients to receive counseling on ways to prevent and treat exercise-induced asthma.
For More Information
Health Behavior News Service: 202-387-2829 or http://www.hbns.org.
Interviews: Contact Felix S.F. Ram at fax
64-9-441-8165 or fsfram@yahoo.co.uk.
Ram, FSF, et al. Physical training for asthma (Review). The Cochrane Database of Systematic Reviews 2005, Issue 4.
The Cochrane Collaboration is an international nonprofit, independent organization that produces and disseminates systematic reviews of health care interventions and promotes the search for evidence in the form of clinical trials and other studies of interventions. Visit http://www.cochrane.org for more information.
By Milly Dawson, Contributing Writer
Health Behavior News Service