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 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. Results: Mean V V E was higher for CE compared to IE (85 ± 17 l.min - 1 vs 50 ± 8 l.min - 1, respectively; P < 0.001). Serum-based markers of epithelial cell damage remained unchanged during IE. Interaction of test × time was observed for SP-D (P = 0.02), CC16 (μg.l - 1) (P = 0.006) and CC16/SP-D ratio (P = 0.03). Maximum delta CC16/SP-D was significantly correlated with mean V V E sustained (r = 0.83, P < 0.001) during CE but not during IE. Conclusion: The 30-min CE performed at 70% WR max induced mild airway damage, while a time- or work-matched IE did not. The extent of the damage during CE was associated with the higher ventilation rate.
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- Minute ventilation
- Type of exercise