Background: While continuous exercise (CE) induces greater ventilation (_ V E) when compared to intermittent exercise (IE), little is known of the consequences on airway damage. Our aim was to investigate markers of epithelial cell damage-i.e. serum levels of CC16 and of the CC16/SP-D ratio-during and following a bout of CE and IE of matched work. Methods: Sixteen healthy young adults performed a 30-min continuous (CE) and a 60-min intermittent exercise (IE; 1-min work: 1-min rest) on separate occasions in a random order. Intensity was set at 70% of their maximum work rate (WR max). Heart rate (HR) and _ V E were measured throughout both tests. Blood samples were taken at rest, after the 10th min of the warm-up, at the end of both exercises, half way through IE (matched time but 50% work done for IE) as well as 30-and 60-min post-exercise. Lactate and CC16 and SP-D were determined.