Exercise alters serum pneumoprotein concentrations

To determine the effect of exercise on serum levels of Clara cell protein ( CC16) and surfactant-associated protein A (SP-A), serum was collected from 14 healthy subjects 1 h after maximal and sub-maximal exercise. Healthy vol unteers participated on separate occasions in a control (no exercise) sessi on, simulated firefighting tasks for 30 min (n = 14), and intermittent trea dmill exercise at near maximal heart rates for 60 min (n = 10). Serum sampl es and induced sputum samples were collected I h post exercise. Induced spu tum fluid was analyzed for tumor necrosis factor alpha (TNF-alpha), an infl ammatory mediator produced by pulmonary macrophages. Serum CC16 levels incr eased significantly with both firefighting tasks (15 +/- 13 mug/L vs. 9 +/- 4 mug/L, P = 0.047) and treadmill exercise (15 +/- 8 mug/L vs. 9 +/- 4 mug /L, P < 0.01). Serum SP-A concentrations did not change compared to control with either firefighting tasks (247 +/- 106 mug/L vs. 247 +/- 96 mug/L, P = 0.84) or treadmill exercise (251 +/- 89 mug/L vs. 285 +/- 87 mug/L, P = 0 .44). TNF-alpha concentrations in sputum supernatant showed no significant difference from controls. These results show an increase in serum CC16 afte r exercise. This must be considered when utilizing serum CC16 to determine the presence of lung injury in settings that combine exercise and toxic exp osures. (C) 2001 Elsevier Science B.V. All rights reserved.