Grant: Master's Award: Canada Graduate Scholarships

Chronic Obstructive Pulmonary Disease (COPD) is a debilitating lung condition most often caused by years of heavy smoking. Patients experience chronic lung hyperinflation, which greatly increases their work of breathing even at rest, such that light exercise becomes nearly intolerable. Patients experience difficulty performing such daily tasks as walking up stairs or washing their hair. 27% of COPD patients in Canada are also obese. Paradoxically, epidemiological and clinical studies have shown that overweight and obese COPD patients may have survival and exercise-performance advantages over normal-weight patients of matched COPD severity. Other studies have confirmed that overweight and obese COPD patients exhibit reduced hyperinflation and improved inspiratory capacity compared to normal-weight controls due to greater restrictive force of the chest wall and lung tissue in the obese state. The objective of my proposed research is to determine if the apparent ""mechanical advantage"" of excess weight in COPD extends from stationary-cycling exercise tests to weight-baring activities such as walking, which are likely to be more important determinants of a patient's quality of life. My proposed study involves incremental exercise tests on both the treadmill and the cycle ergometer for COPD patients of the normal-weight, overweight, and obese BMI categories. Ventilatory parameters and arterial blood pH will be recorded and assessed throughout each trial, the former as an indicators of oxygen consumption and change in tidal volume, and the later as a measure of lactic acid formation. This research is important because the high prevalence of both obesity (24%) and COPD (4%) in Canada leads to a sizeable number of patients with both disorders. Investigation into the physiological consequences of combined obesity and COPD is imperative if comorbid patients are to be appropriately advised and treated.