Prolonged endurance challenge at moderate altitude: effect on serum eosinophil cationic protein, eosinophil dynamics, and lung function.
BACKGROUND
Eosinophils contain granule proteins such as eosinophil cationic protein (ECP) that have proinflammatory effects on airways. ECP may be released on activation of eosinophils into the plasma and is widely used as a marker of bronchial hyperreactivity and allergic inflammation. Environmental factors as well as intense physical exertion may influence eosinophil-related bronchial hyperreactivity.


OBJECTIVE
To investigate the effect of endurance exercise at moderate altitude on levels of circulating eosinophils, serum ECP, serum osmolality (sOS), and dynamic pulmonary function parameters in healthy mountaineers.


METHODS
Alpine field study performed in the Alps of Upper Styria in Austria. Type of exercise: Ascent of a mountain at maximal speed.


METHODS
Thirty healthy male volunteers from a troop of military mountaineers.


RESULTS
Mean ECP concentration increased by 66% at the summit checkpoint (H2) and remained at 63% above baseline (base checkpoint [H0]) after descent (H4), while the blood eosinophil count decreased concomitantly from 250/microL at H0 (preexercise) to 118/microL (53%) at H2 and to 22/microL (81%) at H4. The total serum ECP concentration adjusted to sOS correlated negatively with blood eosinophil count (r = - 0.37; p < 0.0001) and PaO(2) (r = - 0.34; p < 0.001), but positively with the peak expiratory flow (PEF) [r = 0.45; p < 0.0001]. Although sOS correlated with serum ECP at H2 (r = 0.47; p = 0.02) and at 12 h after the start of the experiment (H12) [r = 0.57; p = 0.003], the relationship between total ECP and sOS (r = 0.19; p = 0.034) was less pronounced. FEV(1) in percentage of FVC (%FEV(1)/FVC) [the Tiffenau test], forced expiratory flow rate at 25% of vital capacity, and PEF were significantly higher at H2 than at H0 and H4. %FEV(1)/FVC decreased to 88% (p < 0.01) and 83% (p < 0.001) predicted at H12 and 24 h after start of the experiment, respectively.


CONCLUSIONS
Results provide strong evidence for nonspecific activation of blood eosinophils during prolonged intense aerobic exercise at moderate altitude, modifying both eosinophil dynamics and regulation of ECP release in healthy subjects.
Domej
Wolfgang
W
Department of Internal Medicine, Graz University M. S. and Hospital, Graz, Austria.
Schwaberger
Günther
G
Tilz
Gernot Peter
GP
Földes-Papp
Zeno
Z
Demel
Ulrike
U
Lang
Johanna
J
von Duvillard
Serge Petelin
SP
D000328:Adult; D000532:Altitude Sickness / Q000175:diagnosis / Q000503:physiopathology*; D001798:Blood Proteins / Q000378:metabolism*; D016535:Bronchial Hyperreactivity / Q000175:diagnosis / Q000503:physiopathology; D047091:Eosinophil Granule Proteins; D004804:Eosinophils / Q000502:physiology*; D005080:Exercise Test; D005541:Forced Expiratory Volume / Q000502:physiology*; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D009051:Mountaineering; D010807:Physical Endurance / Q000502:physiology*; D012260:Ribonucleases; D012307:Risk Factors; D014797:Vital Capacity / Q000502:physiology*
D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D012260:Ribonucleases