Interleukins 1-beta,-8, and histamine increases in highly trained, exercising athletes

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.