Lt. Mackinnon et Dg. Jenkins, DECREASED SALIVARY IMMUNOGLOBULINS AFTER INTENSE INTERVAL EXERCISE BEFORE AND AFTER TRAINING, Medicine and science in sports and exercise, 25(6), 1993, pp. 678-683
Endurance athletes have been shown to suffer a high incidence of upper
respiratory tract infection (URTI). Previous studies have shown that
concentration and flow rate of secretory immunoglobulin A (IgA), the m
ajor effector of host resistance to URTI, decrease after intense endur
ance exercise. The purpose of this study was to determine whether sali
vary IgA concentration and flow rate decrease after brief intense inte
rval exercise, and whether the response to exercise changes with train
ing. Twelve male subjects performed five 60-s bouts of supramaximal in
terval exercise at 0.075 g.kg-1 body mass on a cycle ergometer; each b
out was separated by 5-min rest. Subjects then trained for 8 wk by per
forming the same interval exercise protocol three times per week. Time
d, whole unstimulated saliva samples were obtained before and after th
e interval exercise protocol, before and after training. Salivary IgA,
IgG, and IgM concentrations were measured by ELISA and flow rates cal
culated. IgA and IgM concentrations relative to total protein decrease
d after each exercise session; IgG concentration relative to total pro
tein did not change after exercise. IgA, IgM, and IgG flow rates decre
ased 50-65% after interval exercise. There was no effect of training o
n any immune parameter measured, although total work performed in the
five 60-s bouts increased after training. These data show that the out
put of salivary IgA and IgM decrease after brief supramaximal interval
exercise. and that the decreased output is due, at least partially, t
o the decrease in saliva flow. In addition, there appears to be a spec
ific effect of intense exercise on IgA concentration greater than that
due to decreased saliva flow alone. These data suggest that decreases
in secretory IgA output after repeated bouts of supramaximal exercise
may be one mechanism contributing to the high incidence of upper resp
iratory tract infection among athletes.