Despite the increase in asynchrony, both breathing exercises were able to improve chest wall volumes without affecting dyspnea. The combination of exercises maintained the benefits but did not reduce the adverse effects of diaphragmatic breathing.

Subjects with chronic obstructive pulmonary disease (COPD) present breathing pattern and thoracoabdominal motion abnormalities that may contribute to exercise limitation. Twenty-two men with stable COPD (FEV 1 = 42.6 ± 13.5% predicted; age 68 ± 8 years; mean ± SD) on usual medication and with at least 5 years of diagnosis were evaluated at rest and during an incremental cycle exercise test (10 watts/2 min). Changes in respiratory frequency, tidal volume, rib cage and abdominal motion contribution to tidal volume and the phase angle that measures the asynchrony were analyzed by inductive respiratory plethysmography at rest and during three levels of exercise (30-50, 70-80, and 100% maximal work load). Repeated measures ANOVA followed by pre-planned contrasts and Bonferroni corrections were used for analyses. As expected, the greater the exercise intensity the higher the tidal volume and respiratory frequency. Abdominal motion contributed to the tidal volume increase (rest: 49.82 ± 11.19% vs exercise: 64.15 ± 9.7%, 63.41 ± 10%, and 65.56 ± 10.2%, respectively, P < 0.001) as well as the asynchrony [phase angle: 11.95 ± 7.24° at rest vs 22.2 ± 15° (P = 0.002), 22.6 ± 9° (P < 0.001), and 22.7 ± 8° (P < 0.001), respectively, at the three levels of exercise]. In conclusion, the increase in ventilation during exercise in COPD patients was associated with the major motion of the abdominal compartment and with an increase in the asynchrony independent of exercise intensity. It suggests that cycling exercise is an effective way of enhancing ventilation in COPD patients.

Background: Obesity is a worldwide health problem that may also induce respiratory dysfunction. Literature linking weight loss and maximum

This study evaluated the breathing pattern of 30 obese patients [32 ± 9 years old; body mass index (BMI): 42.72 ± 4.10 kg/m(2)] before and after bariatric surgery and compared them with 30 control individuals (31 ± 8 years old, BMI: 21.99 ± 2.22 kg/m(2)). Measurements were performed using calibrated respiratory inductive plethysmography. Six months after bariatric surgery, obese patients exhibited a significant reduction in tidal volume (V(T)), minute ventilation (V(E)) and inspiratory duty cycle (T(I)/T(TOT)) compared with pre-surgical values. The control group had a higher breathing frequency, V(E) and phase angle (PhAng). There were no significant differences in V(T)/T(I), percentage of rib cage motion (%RC) or abdominal motion (%AB). Obese patients exhibited changes in their breathing pattern and asynchrony after bariatric surgery without any changes in thoracoabdominal motion. Certain aspects of the breathing pattern of obese patients became more similar to those of the controls after surgery.

Chest wall volumes and breathing patterns of 13 male COPD patients were evaluated at rest and during inspiratory loaded breathing (ILB). The sternocleidomastoid (SMM) and abdominal muscle activity was also evaluated. The main compartment responsible for the tidal volume at rest and during ILB was the abdomen. During ILB patients exhibited, in addition to increases in the ratio of inspiratory time to total time of the respiratory cycle and minute ventilation, increases (p<0.05) in the chest wall tidal volume by an increase in abdomen tidal volume as a result of improvement of end chest wall inspiratory volume without changing on end chest wall expiratory volume. The SMM and abdominal muscle activity increased 63.84% and 1.94% during ILB. Overall, to overcome the load imposed by ILB, COPD patients improve the tidal volume by changing the inspiratory chest wall volume without modifying the predominant mobility of the abdomen at rest and without affecting the end chest wall expiratory volume.