Purpose: Exercise-induced hypoxemia (EIH) in highly trained athletes is ass
ociated with an increase in histamine release (%H) during exercise. Certain
cytokines, known as histamine-releasing factors, are capable of interactin
g with basophils and/or mast cells to cause the release of histamine. The a
im of this study was to determine whether the increased histamine release i
n highly trained athletes is related to a high plasma level in interleukin-
1 beta (IL-1 beta), IL-3, or IL-8 in arterial blood. Methods: These paramet
ers were measured in 11 endurance athletes (23.2 +/- 1.2 yr (mean +/- SEM))
known to develop exercise-induced hypoxemia and 11 control subjects (25.0
+/- 1.1 yr) at rest, during an incremental exhaustive exercise rest, and at
the fifth minute of recovery. Results: Histamine release increased between
rest and maximal exercise in the athletes (P < 0.01), showing a strong cor
relation with EIH (r = 0.76. P < 0.01) and was unchanged in the controls. I
L-3 plasma concentration was not altered with training and/or with exercise
. Circulating IL-8 levels were not different between trained and untrained
subjects at any testing level and increased at maximal exercise in both gro
ups (P < 0.01). IL-1 beta plasma levels were higher in athletes than in con
trols (P < 0.05) at each testing level and increased during exercise only i
n the athletes (P < 0.05). Conclusion: An elevated concentration of IL-1 be
ta in plasma and its association with increased IL-8 levels during exercise
may partly explain the increase in %H associated with EIH in highly traine
d athletes. Histamine, IL-8, and IL-1 beta releases during exercise reflect
an inflammatory reaction, which is probably involved in EM.