Relationship between salivary IgA secretion and upper respiratory tract infection following a 160-km race.
OBJECTIVE
The relationship between salivary IgA secretion rate and upper respiratory tract infection (URTI) was studied in 155 ultramarathoners (126 males, 29 females, mean age 46.5+/-0.7 y) who had qualified to run the 160-km 2003 Western States Endurance Run.


METHODS
Subjects provided saliva samples during registration, held the morning before the race, and within 5-10 minutes postrace (mean race time, 26.2+/-0.3 h). Unstimulated saliva was collected by expectoration for 4 minutes into 15-mL plastic, sterilized vials. Runners finishing the race and providing pre- and postrace saliva samples (n=106) turned in a health log specifying URTI episodes and severity of symptoms for the 2-week period following the race.


RESULTS
The total volume of saliva that the runners was able to expectorate during sample collection decreased 51% postrace compared to prerace values (P<0.001). Saliva protein concentration increased 20% (P<0.001) while the saliva protein IgA concentration decreased 10% (P<0.05). Salivary IgA secretion rate decreased 46% when comparing pre- to postrace values (P<0.001). Twenty-four percent of the runners finishing the race and providing salivary samples reported an URTI episode lasting 2 days or longer during the 2-week period following the race (mean number of days with symptoms was 5.4+/-0.6 days). The decrease in salivary IgA secretion rate (pre- to postrace) was 53% greater in the 25 runners reporting URTI (-355+/-45 microg/min) compared to the 81 runners not reporting URTI (-232+/-37 microg/min), (P=0.04).


CONCLUSIONS
In summary, nearly 1 in 4 runners reported an URTI episode during the 2-week period following a 160-km race, and the decrease in salivary IgA secretion rate was significantly greater in these runners compared to those not reporting URTI.
Nieman
D C
DC
Department of Health, Leisure and Exercise Science, Appalachian State University, Boone, NC 28608, USA. niemandc@appstate.edu
Henson
D A
DA
Dumke
C L
CL
Lind
R H
RH
Shooter
L R
LR
Gross
S J
SJ
D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012141:Respiratory Tract Infections / Q000276:immunology*; D012420:Running / Q000502:physiology*; D012463:Saliva / Q000276:immunology*
D007070:Immunoglobulin A