In the present study, we found that QF is reduced in patients with IPF, and this weakness correlates with exercise limitation as well as lung function impairment in those patients. Among these variables, VC and QF were particularly significant contributing factors according to the stepwise analysis. To our knowledge, this is the first report clarifying the relationship between peripheral muscle performance and exercise capacity in patients with IPF.
Some factors and mechanisms that determine exercise capacity in ILD have been reported, although those in IPF have not been extensively studied. A decrease in exercise capacity has been reported even in ILD patients who have normal resting pulmonary function results. Thus, directly measuring exercise capacity of patients with ILD is important in evaluating impairment. Factors reported to correlate with exercise limitation in patients with ILD include VC, FEV1, TLC, Dlco, and, possibly, Pa02. Mechanism of exercise limitation in patients with ILD has also been explored. Marciniuk et al described expiratory flow limitation in all patients who stopped exercise due to dyspnea. In the remaining patients who discontinued exercise because of leg fatigue, no flow limitation was evi-dent. Harris-Eze et al reported that patients with ild were able to increase both peak ventilation and exercise performance with supplemental oxygen. This finding suggests a hypothesis that arterial hypoxemia, not ventilatory limitation, limits exercise. As another contributing factor, ventilation-perfusion mismatching, may contribute to exercise limita-tion. Diffusion limitation and circulatory limitation can also affect exercise tolerance of patients with ILD. Hansen and Wasserman reported that Dlco was the best correlate of Vo2max in ILD. It is also suggested that higher respiratory drive during exercise can be attributed to increased afferent reflexes originating from the lung or chest wall, which might thereby limit exercise tolerance. To become familiar with ordering procedure online you may go to the page using the link – canadian health care mall publications on wordpress.