Chest, Vol 103, 745-750, Copyright © 1993 by American College of Chest Physicians

ARTICLES

Altered exercise gas exchange and cardiac function in patients with mild chronic obstructive pulmonary disease

R Carter, B Nicotra, W Blevins and D Holiday
Department of Medicine, University of Texas Health Center, Tyler 75708.

Patients with advanced COPD have significantly reduced gas exchange and pulmonary function; however, little is known regarding physical work capacity and exercise gas exchange in patients with mild COPD. A total of 39 individuals (20 men and 19 women) without evidence of COPD (controls) and 51 individuals (29 men and 22 women) with mild COPD (FEV1 > or = 60 percent of predicted; and ratio of FEV1 over forced vital capacity of 60 to 70 percent) were tested to determine resting pulmonary function and resting and peak exercise gas exchange in response to progressive maximal cycle ergometer testing. In general, those with mild COPD had similar smoking histories and essentially equivalent resting gas exchange studies as compared to the controls. Measured maximal oxygen consumption was less in both the male (p < 0.003) and the female patients (p < 0.001). This was due, in part, to a lower maximal ventilation in the men with obstruction (p < 0.04), resulting from a significant reduction in tidal volume (p < 0.05). Women presented with similar decreases in maximal ventilation (p < 0.04) and maximal tidal volume (p < 0.01), while no difference in maximal respiratory rate was noted in either group (p > 0.05). Breathing reserve was 32 percent and 53 percent less for the male and female patients with obstruction than for controls. Maximal heart rates were less in the individuals with obstruction, where they reached 93 percent (p < 0.02) and 96 percent (p < 0.003) of the age- and sex- specific maximal heart rates for men and women as compared to 101 percent and 99 percent obtained in the controls. Achieved absolute work loads for men and women (in kilogram.meters per minute) were lower in the groups with obstruction (p < 0.002 and 0.0003) as well. These results demonstrate that work capacity and gas exchange are significantly decreased in individuals with even mild COPD. The reduction in functional work capacity is secondary to a loss of pulmonary function, as well as chronic deconditioning. Increased dyspnea may be responsible for the premature cessation of exercise observed in patients with mild COPD. Thus, early intervention with exercise training may be warranted to counter the deleterious effects of deconditioning and declining pulmonary function in patients with mild COPD.

This article has been cited by other articles:

				V. M. Pinto-Plata, R. A. Celli-Cruz, C. Vassaux, L. Torre-Bouscoulet, A. Mendes, J. Rassulo, and B. R. Celli Differences in Cardiopulmonary Exercise Test Results by American Thoracic Society/European Respiratory Society-Global Initiative for Chronic Obstructive Lung Disease Stage Categories and Gender Chest, October 1, 2007; 132(4): 1204 - 1211. [Abstract] [Full Text] [PDF]

				A. Bobbio, A. Chetta, P. Carbognani, E. Internullo, A. Verduri, G. Sansebastiano, M. Rusca, and D. Olivieri Changes in pulmonary function test and cardio-pulmonary exercise capacity in COPD patients after lobar pulmonary resection Eur. J. Cardiothorac. Surg., November 1, 2005; 28(5): 754 - 758. [Abstract] [Full Text] [PDF]

				T. L. Petty Are COPD and Lung Cancer Two Manifestations of the Same Disease? Chest, October 1, 2005; 128(4): 1895 - 1897. [Full Text] [PDF]

				F. C. Sciurba Physiologic Similarities and Differences Between COPD and Asthma Chest, August 1, 2004; 126(2_suppl_1): 117S - 124S. [Abstract] [Full Text] [PDF]

				ATS/ACCP Statement on Cardiopulmonary Exercise Testing Am. J. Respir. Crit. Care Med., January 15, 2003; 167(2): 211 - 277. [Full Text] [PDF]

				T. L. Petty COPD in Perspective* Chest, May 1, 2002; 121(5_suppl): 116S - 120S. [Abstract] [Full Text] [PDF]

				K. O. Hadeli, E. M. Siegel, D. L. Sherrill, K. C. Beck, and P. L. Enright Predictors of Oxygen Desaturation During Submaximal Exercise in 8,000 Patients Chest, July 1, 2001; 120(1): 88 - 92. [Abstract] [Full Text] [PDF]

				M. J. BERRY, W. J. REJESKI, N. E. ADAIR, and D. ZACCARO Exercise Rehabilitation and Chronic Obstructive Pulmonary Disease Stage Am. J. Respir. Crit. Care Med., October 1, 1999; 160(4): 1248 - 1253. [Abstract] [Full Text]