THE ACUTE IMMUNE-RESPONSE TO EXERCISE - WHAT DOES IT MEAN

The purpose of this article is to provide information about the exerci se-induced alteration of cellular immune parameters depending on the i ntensity related to the individual anaerobic threshold (IAT) and durat ion of exercise. Immunological parameters were differential brood coun ts (CD14, CD45), monocyte subpopulations (CD14, CD16), lymphocyte subp opulations (CD3, CD4, CD8, CD45RO, CD19, CD16, CD56, HLA-DR) and natur al killer cells (CD3, CD16, CD56), oxidative burst activity of neutrop hils, and phagocytosis of neutrophils (flow cytometry). The main resul ts were: (a) ''Moderate'' exercise (duration < 2 h at about 85% of the IAT corresponding to a lactate steady state at about 2 mmol.l(-1), < 30 min at the IAT corresponding to a lactate steady state of 4 mmol.l( -1)) elicits lower changes in cell concentrations and hormonal respons es than strenuous exercise [exhaustive exercise at 100% IAT or above; (exhaustive) long-term (> 2-3 h) endurance exercise]. Similar investig ations about cell functions to decide about the positive or negative n ature of these observations will have to follow in the future. (b) The neutrocytosis following exercise is more dependent on the duration th an on the intensity of exercise. Especially exercise sessions that lea d to a strong incline of the adrenocorticotropic hormone, beta-endorph in and cortisol are associated with this neutrocytosis. (c) Neutrophil s' function during the exercise-induced neutrocytosis indicated by pha gocytosis and oxidative burst activity is unchanged or reduced followi ng strenuous endurance exercise, whereas bacterial URTI leads to simil ar neutrophil counts but significantly increased cell activities indic ating the diverse meaning of the leukocytosis in infections (primed ce lls, enhanced cell activity, stimulated defense mechanism) and followi ng exercise (impaired cell function, suppressed defense mechanism). (d ) Regular monocytes (early differentiation stage) are strongly recruit ed into the circulation during long-term aerobic exercise, whereas mat ure monocyte cell counts (premacrophages) increase most with highly in tensive (an)aerobic exercise above the IAT. Infections induce a matura tion from regular to mature monocytes as a response to the infectious antigenic stimulus, whereas exercise does not, indicating the diversit y between change of cell counts and function. (e) Long-term endurance diverse meaning reads to increases of activated CD45RO(+) T cells (mem ory cell phenotype) but compared to the incline of cell concentrations and activation levels (% HLA-DR+ T-cells) during infections like infe ctious mononucleosis this effect is small indicating only minor effect s on T cell function by exercise. The effect of single bouts of exerci se on immune cell counts is large but the effects on the cell function is - i.e. compared to bacterial URTI - relatively small.