Salivary immunoglobulin A response at rest and after exercise following a 48 h period of fluid and/or energy restriction.
The aim was to investigate the effects of a 48 h period of fluid, energy or combined fluid and energy restriction on salivary IgA (s-IgA) responses at rest and after exercise. Thirteen healthy males (age 21 (sem 1) years) participated in four randomised 48 h trials. In the control trial participants received their estimated energy (12,154 (sem 230) kJ/d) and water (3912 (sem 140) ml/d) requirements. On fluid restriction (FR) participants received their energy requirements and 193 (sem 19) ml water/d to drink and on energy restriction (ER) participants received their water requirements and 1214 (sem 25) kJ/d. Fluid and energy restriction (F+ER) was a combination of FR and ER. After 48 h, participants performed a 30 min treadmill time trial (TT) followed by rehydration (0-2 h) and refeeding (2-6 h). Unstimulated saliva was collected at 0, 24 and 48 h, post-TT, and 2 and 6 h post-TT. Saliva flow rate (sflw) and s-IgA (ELISA) remained unchanged in control conditions and on ER. However, 48 h on FR decreased sflw (64 %) which most probably accounted for the increase in s-IgA concentration (P < 0.01). Despite a decrease in sflw (54 %), s-IgA concentration did not increase on F+ER, resulting in a decreased s-IgA secretion rate by 24 h (0 h: 20 (sem 2); 24 h: 12 (sem 2) microg/min; P < 0.01). Post-TT s-IgA secretion rate was not lower compared with 48 h on any trial. s-IgA secretion rate returned to within 0 h values by 6 h post-TT on F+ER. In conclusion, a 24-48 h period of combined F+ER decreased s-IgA secretion rate but normalisation occurred upon refeeding.
Oliver
Samuel J
SJ
School of Sport, Health and Exercise Sciences, University of Wales, Bangor LL57 2PZ, UK.
Laing
Stewart J
SJ
Wilson
Sally
S
Bilzon
James L J
JL
Walters
Robert
R
Walsh
Neil P
NP
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D004032:Diet; D004326:Drinking / Q000502:physiology; D002149:Energy Intake / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005508:Food Deprivation / Q000502:physiology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007071:Immunoglobulin A, Secretory / Q000378:metabolism*; D008297:Male; D010953:Plasma Volume; D012463:Saliva / Q000276:immunology*; D012472:Salivation; D013048:Specimen Handling / Q000379:methods; D014868:Water Deprivation / Q000502:physiology*
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007071:Immunoglobulin A, Secretory; D006854:Hydrocortisone