50-MILE WALKING RACE SUPPRESSES NEUTROPHIL BACTERICIDAL FUNCTION BY INDUCING INCREASES IN CORTISOL AND KETONE-BODIES

To examine the effect of intensive aerobic exercise on the interaction between endocrine and immune systems, we studied in ten normal health y male subjects the effect of a 50-mile walking race on blood concentr ation of hormones (insulin, GH, ACTH, cortisol, adrenaline, noradrenal ine, and dopamine), ketone bodies, specific immunological functions (I gG, IgM, and PHA/Con A-induced lymphocyte blastformation test), and no nspecific immune (CH50, and neutrophil bactericidal functions). Neutro phil bactericidal activity was measured as chemiluminescences amplifie d by luciferin analog (CLA-DCL) and luminol (L-DCL). The race increase d cortisol and ketone bodies, and decreased insulin, CLA-DCL, and L-DC L (all parameters; P<0.01). However, other parameters were not signifi cantly changed. There were significant negative correlations between c hanges of ketone bodies/cortisol and CLA/L-DCL (P<0.05), however there was no significant correlations between changes of insulin and CLA/L- DCL. These data indicate that extensive aerobic exercise causes impair ed neutrophil bactericidal function, probably due to the induced incre ases in both cortisol and ketone bodies. This impaired neutrophil func tion may cause the susceptibility to infection after an extensive exer cise.