Grant: Operating Grant

Chronic Obstructive Pulmonary Disease (COPD) is defined as a respiratory disorder largely caused by smoking and characterized by airway obstruction. While originally considered a disease specific to the lung, typified by breathlessness with exercise, it is now appreciated that there are important secondary issues that develop as a result of COPD such as cardiovascular disease. COPD patients are almost three times more likely to die of heart failure than smokers not diagnosed with COPD, indicating that it is something specific to the disease of COPD, and not simply smoking history that is causing cardiovascular disease. COPD patients have increased resting sympathetic activity. While initially beneficial, chronically elevated sympathetic activity results in cardiovascular disease and increased mortality. Importantly, the exact cause for the increased sympathetic activity in COPD is unknown. We believe that the carotid chemoreceptors (CC) are important in regulating the sympathetic nervous system and cardiovascular function in COPD. Like heart failure, we believe that there is an increased sympathetic nervous response to exercise in COPD due to increased CC activity, which reduces muscle blood flow and decreases exercise capacity. We will perform experiments to modify CC activity at rest and during exercise to determine how this affects sympathetic activity and blood flow in COPD. Exercise training is now recognized as an important therapy for COPD. Exercise training has been shown to improve exercise capacity, quality of life and may even improve mortality in COPD; however, the physiological adaptations from rehab are not well understood. Based on previous work, we believe that exercise training will improve: CC activity, sympathetic activity and cardiovascular function in COPD. These studies will help to understand why COPD are at increased risk of developing cardiovascular disease, and help us understand how to improve functioning in COPD.