Exercise and diet improve asthma controlin non-obese asthma patients - a randomised controlled trial

Background: Behavioural interventions focusing on physical training and healthy diet have been found to improve asthma control in obese asthma patients, but if these interventions also improve asthma control in non-obese patients remains unclear. Objective: In a randomised, controlled parallel-group design, we studied the effects of an 8-week intervention of either diet (high protein/low glycaemic index plus at least 6 servings of fruit and vegetables/day), exercise (high intensity interval training three times/week) or a combination of the two, on asthma control, quality of life and clinical outcomes in non-obese asthma patients. Methods: 149 non-obese adult asthma patients were randomised to one of four groups: an exercise group, a diet group, an exercise+diet group or a control group (usual care). Level of asthma control (ACQ), asthma related quality of life (AQLQ), forced expiratory volume in one second (FEV1), airway hyperresponsiveness (AHR) and fractional exhaled nitric oxide (FeNO) levels were measured pre- and post intervention. Results: 125 patients completed the study and were included in the data analysis. Patients in the exercise+diet group had a significant reduction in ACQ and a significant improvement in AQLQ (mean change (95%CI) compared to change in the control group (-0.6 (-1.0;-0.2), (p<0.01) and (0.5 (0.1;0.9, p<0.01), respectively. There were no significant changes within any groups in FEV1, AHR or FeNO. Conclusion: Eight weeks of combined exercise and diet improves asthma control in non-obese asthma patients, but does not affect objective measurements of airway pathophysiology.