Description
Intervention design: After baseline screening and testing, all 60 eligible participants were allocated to the BTE (breathing exercises) or IMT (inspiratory muscle training) group by a third person in a blinded manner (i.e., only using the subject number without knowledge of any other identification or baseline test result) using block randomization targeting group sizes of n = 30.
During the 12-week program, the BTE group participated in 25-min sessions twice a week. The sessions focused on stimulating nasal and diaphragmatic breathing, increasing the expiratory time, slowing the respiratory flow, and regulating the breathing rhythm. At the beginning of each session, the participants performed exercises to stretch the muscles of the thoracic wall. These exercises were followed by respiratory exercises and exercises to strengthen the abdominal and diaphragmatic muscles. All of the exercises were associated with diaphragmatic breathing and pursed-lip breathing.
Participation in the IMT group required 30 dynamic inspiratory efforts two times per day, five days per week, for 12 weeks. The intensity of each breath was 50–60% of maximal inspiratory pressure (PImax). The participants were instructed to initiate each breath from residual volume and to continue the inspiratory effort until the maximal lung pressure was attained for at least one second. This procedure was repeated three times. A nose clip was worn during all breaths, and the participants were instructed to maintain a low breathing frequency to avoid hyperventilation. The initial training loads were set by the investigators, and all of the inspiratory efforts were trained using a pressure-threshold device. The participants were instructed to periodically increase the resistive load such that the completion of 30 breaths approximated the limit of inspiratory muscle tolerance.
People involved: Sixty thoracic outpatients, who were attending a follow-up clinic at a regional medical center in northern Taiwan in age between 40 and 65 years, diagnosed with asthma for more than six months by a specialist doctor.
G1: 30 (BTE), G2: 30 (IMT), Age: G1: 55.1 (±7.72), G2: 55.1 (±6.68)
The exclusion criteria were: (1) chronic obstructive pulmonary disease or other lung diseases; (2) lung cancer or other terminal tumors; (3) long-term use of oxygen therapy at home; (4) long-term use of a noninvasive positive pressure breathing apparatus; (5) unable to consent and cooperate; (6) active tuberculosis or other infectious diseases; (7) acute pneumonia infection in the past month; (8) untreated hypertension; (9) stroke; (10) presence of any diseases related to the brain, lungs, or cardiovascular system; and (11) ongoing dialysis treatment.
Identified barriers: The number of samples in this study was small, so the findings may be difficult to generalize to all asthma patients. Larger samples should be collected in the future.
The long-term effects of the training are still unknown. Whether the training had differential effects based on different training times and training intensities remains to be revealed. In future studies, the effects of the intervention can be followed up for a longer time to be validated as clinical indicators.
Sustainability
Transferability: asthma patients