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 were made of plasma concentration of catecholamines (chromatography) and cortisol (RIA) in a search for neuroendocrine markers. The results showed the greatest 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 months (r(2) = 0.998 for monocytes and r(2) = 0.674 for granulocytes). No good correlations were found between phagocytosis and norepinephrine or cortisol. The highest values for phagocytosis and epinephrine concentration were found in May. These results suggest that blood epinephrine concentration could be a good neuroendocrine marker of sportspeople's phagocytic response.

Physiology and biochemistry: influence of exercise on phagocytosis.

Phagocytic cells constitute the organism's first line of defence against external aggression. These cells carry out their non-specific defence function through what is known as the phagocytic process. This can be split up into several stages: adherence, chemotaxis, attachment, ingestion and killing of the foreign agent. The influence of exercise on the phagocytic process is dependent on the step considered, but in general, different responses have been observed in the adherence and chemotaxis capacities depending both on the intensity of exercise and on the phagocyte (neutrophil or monocyte-macrophage) studied. However, with respect to the attachment and ingestion of antigen, exercise generally induces an increase in every "situation", independent of the intensity of physical activity and the involvement of neutrophils or macrophages. The results with regard to the microbicide capacity that have been obtained up to the present time are very contradictory, showing perhaps a greater dependence on the phagocyte studied and on the intensity of exercise. This fact may be due to different methods used in the studies. One could conclude that exercise stimulates certain stages of the phagocytic process. This stimulation could counterbalance the decreased lymphoid activity after certain types of exercise that some authors have reported.