Exercise could reduce risk of asthma symptoms or attacks

The Cochrane LibraryMay 19 2012

Not only is it safe for people with asthma to exercise, but doing so could reduce their risk of asthma symptoms or attacks, according to a new evidence review in The Cochrane Library.

Many people with asthma report avoiding exercise because they're afraid it could trigger symptoms including shortness of breath, wheezing or a full-blown asthma attack, said review author Kristin V. Carson. These fears might be encouraged from misreading their symptoms, their family's beliefs about exercise and asthma, or even from their physicians.

Over time, Carson explains, patients can become out of shape, losing muscle mass and cardiovascular fitness. That makes any future attempts at physical activity significantly harder, increasing the chances that patients will become fatigued and breathless and further discouraging physical activity.

"This results in a spiraling cycle," she says, in which patients are even more likely to avoid exercise.

To determine whether exercise was a danger to asthmatics, Carson and her colleagues reviewed previous studies that looked at the effects of physical training on people with asthma , comparing patients who received no or minimal physical activity to those who exercised for at least 20 minutes, twice a week, over the course of four weeks.

The researchers found that the patients who had exercised—using physical training as varied as running outdoors or on a treadmill, cycling, swimming or circuit training—were no more likely to have a serious asthma-related problem than those who weren't exercising or who did light exercising such as yoga. Additionally, Carson said, their findings showed that patients in exercise programs improved their cardiovascular fitness, which in turn could reduce asthma symptoms over time. Some limited evidence from the included studies also suggested that exercise improved patients' quality of life, she added, which could contribute to other health benefits and improved psychological well-being.

"We found no reason for people with stable asthma to refrain from regular exercise," Carson said. "Physicians should encourage their patents with stable asthma to engage in physical training programs."

Len Horowitz, M.D., a pulmonary specialist at Lenox Hill Hospital in New York City who wasn't involved in this review, agrees that asthma patients shouldn't shy away from exercise. However, even though research suggests that exercise is safe for asthmatics, he says that many people will still use their asthma as a reason to avoid physical activity. "Not everyone wants to exercise," he said. "When patients think exercise makes them symptomatic or makes them risk an attack, it's a good excuse not to do it."

Horowitz notes that may professional athletes have asthma, which hasn't negatively affected their careers. However, he explains, some patients do have exercise-induced asthma, in which vigorous or prolonged exercise can trigger symptoms. He advises patients in his practice to take precautions if they're susceptible, including pre-treating themselves with an albuterol inhaler, avoiding exercise that exposes their lungs to cold, dry air (such as running outside in the winter) and building their activity levels gradually.