EFFECT OF A SINGLE BOUT OF MODERATE INTENSITY EXERCISE ON LEVELS OF SALIVARY IMMUNOGLOBULIN A IN WOMEN EXERCISERS

Gail Kasiri¹, Steve Bird², James Balmer³, Michael Gleeson⁴, 1 Department of Sport and Exercise Science, Canterbury Christ Church University College, Canterbury, United Kingdom, CT1 1QU, 2 Centre for Rehabilitation, Exercise and Sport Science, Victoria University, Melbourne, MC8001, Australia, 3 Liverpool Hope University College, Hope Park, Liverpool, United Kingdom, L16 9JD, 4 School of Sport and Exercise Sciences, University of Birmingham, United Kingdom, B15 2TT.

The purpose of the study was to assess the acute effects of single bouts of moderate intensity exercise on levels of s-IgA. Fifteen women (mean ± s: age 33.5 ± 6.9 years) participated in the study. On two occasions, saliva samples were collected within 5 min of commencing and 5 min of finishing a one hour step aerobics class. On two non-exercise days, subjects provided further saliva samples taken at times corresponding to the pre- and post-exercise class collections. Saliva samples were collected using a cotton swab (Salivette, Sarstedt, Leicester, England) placed under the tongue for 5 min and then stored at -20°C. Prior to analysis the frozen cotton swabs were thawed and centrifuged at 1500·g for 5 min to extract the saliva. Each sample was analysed for s-IgA concentration using a sandwich-type ELISA, saliva flow rate and s-IgA secretion rate. Repeated measures 2 way ANOVA (Exercise vs Control and Pre vs Post) indicated statistically significant interactions, with the exercise condition producing increased s-IgA concentration (mg·l^-1) (mean ± s) (Exercise pre = 28 ± 15, Exercise post = 41 ± 31, Control pre = 35 ± 29, Control post = 31 ± 23, P = 0.015), increased s-IgA secretion rate (µg·min^-1) (Exercise pre = 10 ± 6, Exercise post = 12 ± 8, Control pre = 12 ± 10, Control post = 11 ± 9, P = 0.033) and decreased saliva flow rate (µl·min^-1) (Exercise pre = 347 ± 110, Exercise post = 312 ± 110, Control pre = 325 ± 142, Control post = 345 ± 105, P = 0.043). These findings suggest that a single bout of moderate intensity exercise can acutely increase levels of salivary immunoglobulin A. This effect could potentially contribute to the reduced risk of URTI when moderate exercise is performed on a regular basis.