INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is characterized by an airflow limitation that is usually progressive. The progression of COPD expressed as the rate of an annual decline in FEV ₁ is very heterogeneous. Exercise capacity in COPD patients is often diminished and becomes worsened over the time. The purpose of the study was to examine how the change in FEV ₁ and exercise capacity would deteriorate over long-term observation.

MATERIAL AND METHODS: A total of 22 men with COPD were examined. At the beginning the average age was 59 ± 8.1 years and the mean post-bronchodilator FEV ₁ was 52 ± 14.9% predicted. Pulmonary function testing was performed at entry and then each year for 10 years, and exercise testing on a cycle ergometer was performed at entry and after 10 years.

RESULTS: FEV ₁ and maximum oxygen uptake (VO2max), maximum mechanical work (W _max ), maximum minute ventilation (V _Emax ) and maximum tidal volume (V _Tmax ) declined significantly over the observation time. The mean annual decline in FEV ₁ was 42 ± 37 mL, and the mean decline for VO _2max was 30 ± 15 mL/min/yr and 0.44 ± 0.25 mL/min/kg/yr. Regression analysis revealed that the changes in FEV ₁ do not predict changes in VO2max. We observed a correlation between the annual change in V _Emax and annual change in VO2max (r = 0.51 p < 0.05). The baseline FEV ₁ (expressed as a percentage of predicted and in absolute values) is the predictor of FEV ₁ annual decline (r = 0.74 and 0.82; p < 0.05).

CONCLUSIONS: We observed over time deterioration in exercise capacity in COPD patients which is independent of decline in airflow limitation. The long term follow-up of exercise capacity is important in monitoring of COPD patients in addition to pulmonary function.