Impaired exercise ventilatory efficiency in smokers with low transfer factor but normal spirometry

Extract

It has long been established that severe decrements in transfer factor for carbon monoxide (T_LCO) are associated with negative outcomes in patients with chronic obstructive pulmonary disease (COPD), including exertional hypoxaemia and poor exercise tolerance [1]. More recently, exercise capacity has been found to be diminished in smokers both with and without airflow limitation, with mild-to-moderate decrements in T_LCO [2–4]. The mechanisms that link reduced T_LCO to low exercise capacity in smokers without COPD, even in the absence of increased hypoxic drive or overtly abnormal lung mechanics remain unknown.