577
The Effect of Exercise Training on Salivary Immunoglobulin A and Cortisol Responses to Maximal Exercise S. L. McDowell, R. A. Hughes, R. J Hughes, T .1 Housh, G. 0. Johnson Center for Yough Fitness and Sports Research, University of Nebraska-Lincoln, Lincoln, Nebraska
of upper respiratory infection (URI) has been reported following marathon and ultra-marathon races (14,16) as well as in athletes undergoing high-intensity training (3). Tomasi et a!.
S. L. McDowell, R. A. Hughes, R. J Hughes, T .1 Housh and G. 0. Johnson, The Effect of Exercise Training on Salivary Immunoglobulin A and Cortisol Responses to Maximal Exercise. mt j Sports Med, Vol 13, No 8, pp 577
(22) have suggested that an exercise-induced decrease in salivary levels of immunoglobulin A (s-IgA), which is the first line of defense against potentially pathogenic viruses (21,23), may contribute to this increased incidence of URI. Recently,
—580, 1992.
Mackitmon et a!. (11) found that episodes of URI were
The salivary immunoglobulin A (s-IgA) and cortisol responses to maximal exercise were examined in 24
preceded by decreases (22—27%) in s-IgA concentrations after exercise and suggested that large changes in mucosal IgA occurring during exercise may be related to an increased incidence of URI in elite athletes." This hypothesis is supported by studies by Tomasi et al. (22) and Mackinnon et al. (10), who reported mean decreases of 43 and 65% in s-IgA immediately following an exhaustive cross-country ski race and 2 hours of cycle ergometry, respectively.
Accepted: August 14, 1992
adult males (X±SD; 22.1
before and after 10
weeks of run training. The subjects performed an incremental treadmill test to exhaustion and were randomly assigned to one of three groups: control (CON; n = 5), low intensity training (LO; n = 8), or high intensity training (HI; n = 11). Following the ten weeks of training, the subjects performed a second maximal treadmill test. Saliva samples were collected before, as well as immediately and 1 hr following each of the maximal treadmill tests and were analyzed for s-IgA and salivary cortisol.
Maximal oxygen consumption (VO2max) increased significantly (p
1.15 (13). Heart rate values were recorded every minute throughout the test using a UNIQ CIC Heart Watch (Model 87999) Cardiomonitor System (9). Gas exchange parameters (V02, VCO2, and VE) were analyzed using a calibrated Sensormedics Horizon Metabolic Measurement Cart (Sensormedics Corporation, Anaheim, CA) as the subject breathed through a Hans Rudolph valve. The subjects completed maximal treadmill tests prior to and following the training (48 to 72 hr after the final training session) at the same time of day.
Saliva Collection and Assay
Unstimulated saliva samples were collected before as well as immediately (within 5 minutes) and one hour following each of the maximal treadmill tests. The saliva was collected in Fisher (Pittsburgh, PA 15219) l2ml plastic urine collection tubes, immediately frozen and stored at —20 'C for analysis.
Salivary IgA concentrations were determined by an enzyme linked immunosorbent assay (ELISA) (5) using Sigma reagents. Polyvinyl chloride plates were incubated for 12
hours with rabbit anti-human IgA antibodies diluted in a phosphate buffered saline (PBS) solution (30111 anti-IgA: 5,970
j.tl PBS). The following day the saliva samples were thawed,
centrifuged at 2,000 rev min1 for 10 minutes, diluted with PBS (101 saliva: 4901 PBS) and 50i.tl of each were incubated
with the plated rabbit anti-IgA antibodies. Using Sigma's human liquid IgA (human IgA, Sigma 2636), known concentrations of IgA were also plated to establish standard values. After three washings, 50111 of goat anti-IgA conjugated to alka-
line phosphatase was added to the plates (6 pA of conjugate: 6 ml buffer) and allowed to incubate overnight. After washing, phosphatase substrate (150 Ill) (dilution 8mg substrate: 20 ml of substrate buffer) was added to the wells and the color intensity produced after 25 minutes was measured by a spectrophotometer at 405 nm. All the samples were assayed in duplicate and an average of the absorbance values was used as the representative value. Regression analysis using the relationship of standard IgA concentrations and amount of absorbance (nm) was used to interpolate the concentration of IgA in the samples. Inter-assay and intra-assay coefficients of variation were not conducted for this assay. However previous investigations in this laboratory showed that there were no significant differences between duplicate values. Salivary cortisol was assayed using a magnetic antibody immunoassay (MAIA) kit (manufactured by Serono Diagnostics and distributed by Diba-Corning Diagnos-
tics, E. Walpole, Massachusetts). This kit was modified for saliva as follows: the cortisol standards and serotest control were diluted 1:9 with phosphate buffered saline; 200 j.tl of each sample, control and cortisol standard, were used; 50 !.tl of cortisol tracer and antibody suspension were used, 1125 was the tracer used, and the incubation time was 45 minutes at room temperature. Inter-assay and intra-assay coefficients of variation were 5.0 to 5.9 and 2.8 to 5.4 percent, respectively.
Training Protocol The subjects were randomly assigned to one of three groups: control (CON; n = 5), low intensity training (LO; n = 8), and high intensity training (HI; n = II). Originally, 30 subjects were recruited and assigned to the groups (CON = 6, LO = 12 and HI = 12). The lower number of subjects in each group at the end of the training was a result of attrition and/or injury. The control group did not train during the study while the other groups ran for 20 minutes, three times per week for
ten weeks at a heart rate corresponding to 70% (LO group) or 86% (HI group) of maximal values. These heart rate percent-
ages have been classified by the American College of Sports Medicine (2) as moderate (LO) and heavy (HI) exercise intensities. All training sessions were supervised and the training intensity was monitored using UNIQ CIC Heart Watch Cardiomonitors.
Univariate 2 x 3 x 3 mixed factorial ANOVA with Tukey post-hoc comparisons were used to test for statistical significance (alpha = p
The Effect of Exercise Training on Salivary Immunoglobulin A and Cortisol Responses to Maximal Exercise S. L. McDowell, R. A. Hughes, R. J Hughes, T .1 Housh, G. 0. Johnson Center for Yough Fitness and Sports Research, University of Nebraska-Lincoln, Lincoln, Nebraska
of upper respiratory infection (URI) has been reported following marathon and ultra-marathon races (14,16) as well as in athletes undergoing high-intensity training (3). Tomasi et a!.
S. L. McDowell, R. A. Hughes, R. J Hughes, T .1 Housh and G. 0. Johnson, The Effect of Exercise Training on Salivary Immunoglobulin A and Cortisol Responses to Maximal Exercise. mt j Sports Med, Vol 13, No 8, pp 577
(22) have suggested that an exercise-induced decrease in salivary levels of immunoglobulin A (s-IgA), which is the first line of defense against potentially pathogenic viruses (21,23), may contribute to this increased incidence of URI. Recently,
—580, 1992.
Mackitmon et a!. (11) found that episodes of URI were
The salivary immunoglobulin A (s-IgA) and cortisol responses to maximal exercise were examined in 24
preceded by decreases (22—27%) in s-IgA concentrations after exercise and suggested that large changes in mucosal IgA occurring during exercise may be related to an increased incidence of URI in elite athletes." This hypothesis is supported by studies by Tomasi et al. (22) and Mackinnon et al. (10), who reported mean decreases of 43 and 65% in s-IgA immediately following an exhaustive cross-country ski race and 2 hours of cycle ergometry, respectively.
Accepted: August 14, 1992
adult males (X±SD; 22.1
before and after 10
weeks of run training. The subjects performed an incremental treadmill test to exhaustion and were randomly assigned to one of three groups: control (CON; n = 5), low intensity training (LO; n = 8), or high intensity training (HI; n = 11). Following the ten weeks of training, the subjects performed a second maximal treadmill test. Saliva samples were collected before, as well as immediately and 1 hr following each of the maximal treadmill tests and were analyzed for s-IgA and salivary cortisol.
Maximal oxygen consumption (VO2max) increased significantly (p
1.15 (13). Heart rate values were recorded every minute throughout the test using a UNIQ CIC Heart Watch (Model 87999) Cardiomonitor System (9). Gas exchange parameters (V02, VCO2, and VE) were analyzed using a calibrated Sensormedics Horizon Metabolic Measurement Cart (Sensormedics Corporation, Anaheim, CA) as the subject breathed through a Hans Rudolph valve. The subjects completed maximal treadmill tests prior to and following the training (48 to 72 hr after the final training session) at the same time of day.
Saliva Collection and Assay
Unstimulated saliva samples were collected before as well as immediately (within 5 minutes) and one hour following each of the maximal treadmill tests. The saliva was collected in Fisher (Pittsburgh, PA 15219) l2ml plastic urine collection tubes, immediately frozen and stored at —20 'C for analysis.
Salivary IgA concentrations were determined by an enzyme linked immunosorbent assay (ELISA) (5) using Sigma reagents. Polyvinyl chloride plates were incubated for 12
hours with rabbit anti-human IgA antibodies diluted in a phosphate buffered saline (PBS) solution (30111 anti-IgA: 5,970
j.tl PBS). The following day the saliva samples were thawed,
centrifuged at 2,000 rev min1 for 10 minutes, diluted with PBS (101 saliva: 4901 PBS) and 50i.tl of each were incubated
with the plated rabbit anti-IgA antibodies. Using Sigma's human liquid IgA (human IgA, Sigma 2636), known concentrations of IgA were also plated to establish standard values. After three washings, 50111 of goat anti-IgA conjugated to alka-
line phosphatase was added to the plates (6 pA of conjugate: 6 ml buffer) and allowed to incubate overnight. After washing, phosphatase substrate (150 Ill) (dilution 8mg substrate: 20 ml of substrate buffer) was added to the wells and the color intensity produced after 25 minutes was measured by a spectrophotometer at 405 nm. All the samples were assayed in duplicate and an average of the absorbance values was used as the representative value. Regression analysis using the relationship of standard IgA concentrations and amount of absorbance (nm) was used to interpolate the concentration of IgA in the samples. Inter-assay and intra-assay coefficients of variation were not conducted for this assay. However previous investigations in this laboratory showed that there were no significant differences between duplicate values. Salivary cortisol was assayed using a magnetic antibody immunoassay (MAIA) kit (manufactured by Serono Diagnostics and distributed by Diba-Corning Diagnos-
tics, E. Walpole, Massachusetts). This kit was modified for saliva as follows: the cortisol standards and serotest control were diluted 1:9 with phosphate buffered saline; 200 j.tl of each sample, control and cortisol standard, were used; 50 !.tl of cortisol tracer and antibody suspension were used, 1125 was the tracer used, and the incubation time was 45 minutes at room temperature. Inter-assay and intra-assay coefficients of variation were 5.0 to 5.9 and 2.8 to 5.4 percent, respectively.
Training Protocol The subjects were randomly assigned to one of three groups: control (CON; n = 5), low intensity training (LO; n = 8), and high intensity training (HI; n = II). Originally, 30 subjects were recruited and assigned to the groups (CON = 6, LO = 12 and HI = 12). The lower number of subjects in each group at the end of the training was a result of attrition and/or injury. The control group did not train during the study while the other groups ran for 20 minutes, three times per week for
ten weeks at a heart rate corresponding to 70% (LO group) or 86% (HI group) of maximal values. These heart rate percent-
ages have been classified by the American College of Sports Medicine (2) as moderate (LO) and heavy (HI) exercise intensities. All training sessions were supervised and the training intensity was monitored using UNIQ CIC Heart Watch Cardiomonitors.
Univariate 2 x 3 x 3 mixed factorial ANOVA with Tukey post-hoc comparisons were used to test for statistical significance (alpha = p
