Allostatic stress load and CMV serostatus impact immune response to maximal exercise in collegiate swimmers.

Collegiate athletes are exposed to varying levels of academic and physical stressors, placing them at increased risk for stress-activated latent viral infections. However, the impact of allostatic stress load on the immune response to maximal exercise in athletes remains largely unknown.

PURPOSE: This study examined the effects of a seven-month training period and Cytomegalovirus (CMV) serostatus on immune cell response to high-intensity swim tests within a group of collegiate swimmers.

METHODS: Samples were collected from fifteen NCAA DI swimmers (9 M, 6 F: 19.87 ± 0.64 yrs) before and after exhaustive in-pool swims at 2 time points (V1 : immediately post-season one and V3 : beginning of season two). An additional off-season (V2 ) time point was collected in a subset of 9 swimmers. NK-cell, B-cell, and T-cells were quantified by flow cytometry. Linear mixed models were used to determine the effects of exercise, time point, and CMV serostatus (α=0.05).

RESULTS: Resting senescent CD8+ T-cells were higher in CMV seropositive participants at V3 (p = 0.005). CMV seronegative participants had a decrease in resting senescent CD8+ T-cells from V1 to V3 (p = 0.021). After acute exercise, CMV seropositive participants had lower naïve CD8+ T-cells (p < 0.001) and higher senescent CD8+ T-cells (p < 0.0015). Increased cumulative stress levels did not appear to affect B-cells and NK-cells compartments.

DISCUSSION: Immune response to exercise was impacted by CMV serostatus and allostatic stress load. Young CMV seropositive athletes exposed to elevated stressors should be monitored to determine long-term effects of training and academic stressors.