London, June 15 (IANS): Aerobic exercise may help curb the severity of asthma symptoms and improve quality of life, says a new research.

While people with asthma often avoid exercise for fear of triggering symptoms, new research suggests that aerobic exercise should be routinely added to the drug treatment of moderate to severe asthma.

"These results suggest that adding exercise as an adjunct therapy to pharmacological treatment could improve the main features of asthma," said the authors of the study published online in the journal Thorax.

Celso Carvalho from University of Sao Paulo, Brazil and colleagues compared the impact of aerobic training and breathing exercises on the severity of symptoms in 58 people with moderate to severe asthma.

All the participants, who were aged between 20 and 59, were randomly assigned to either a 30-minute yoga breathing exercise twice a week for 12 weeks, or the breathing exercise plus a 35-minute indoor treadmill session twice weekly for three months.

Their bronchial hyperresponsiveness, or BHR for short, was tested at the beginning and end of the three month monitoring period. BHR indicates the speed of airway constriction and inflammation, a hallmark of asthma.

Levels of proteins (cytokines) generated during the inflammatory response were also assessed before and after the trial. And they filled in a validated quality of life questionnaire for asthma.

Forty-three people (21 in the breathing group and 22 in the breathing plus aerobic exercise group) completed the study.

At the end of the study, BHR had fallen in those in the aerobic exercise group. But BHR did not change in those just given the breathing exercises. Levels of some cytokines also fell significantly among those in the aerobic exercise group, while the number of symptom free days increased. And bouts of worsening symptoms were fewer than in the breathing group.

Quality of life score rose significantly in 15 people in the aerobic exercise group, while maximum oxygen intake and aerobic power increased.