Phagocytic function in cyclists: correlation with catecholamines and cortisol

Flow cytometer measurements were made of the basal variations in peripheral blood functional monocytes and granulocytes over the course of a training season (January to November) of a cycling team. Parallel determinations wer e made of plasma concentration of catecholamines (chromatography) and corti sol (RIA) in a search for neuroendocrine markers. The results showed the gr eatest phagocytic capacity to occur in the central months (March, May, and July), coinciding with the greatest number and highest level of competitive events with good correlation with a peak in epinephrine during these month s (r(2) = 0.998 for monocytes and r(2) = 0.674 for granulocytes). No good c orrelations were found between phagocytosis and norepinephrine or cortisol. The highest values for phagocytosis and epinephrine concentration were fou nd in May. These results suggest that blood epinephrine concentration could be a good neuroendocrine marker of sportspeople's phagocytic response.