RESUMO
BACKGROUND: Previous reports indicate that regular, but not excessive, exercise can moderate the response to anxiety and alter the immune response, therefore we hypothesized that college student athletes who were actively participating on an NCAA Division III athletics team ("in-season") would have lower levels of anxiety and higher salivary IgA levels than similar college athletes who were in their "off-season". NCAA Division III athletes participate in athletics at a level of intensity that is more moderate compared to other NCAA divisions. Alterations in the microbiome have been associated with alterations in psychosocial well-being and with exercise. Therefore, we also proposed that the oral microbiota would be different in "in-season" versus "off-season" athletes. METHOD: In this pilot study, nineteen female students participating on a NCAA Division III athletic team (hockey="in-season"; soccer="off-season") were compared for level of fitness (modified Balke test of VO2 max), salivary IgA levels by immunoassay, anxiety (using a GAD-7 survey), salivary cortisol levels by immunoassay, and numbers of culturable bacteria by growth of CFU/ml on blood agar, mitis salivarius agar and Staphylococcus 110 agar. RESULTS: The proportion of subjects reporting "severe anxiety" on an anxiety scale (GAD-7) were significantly greater in the "off-season" group compared to the "in-season" group (p=0.047, Chi-squared test). "In-season" athletes had significantly higher salivary IgA/total protein levels than "off-season" athletes (one-sided Student's t-test; p=0.03). Cortisol levels were not significantly different in the two groups. The total culturable bacteria counts were higher among "in-season" athletes (p=0.0455, Wilcoxon Rank Sum test), as measured by CFUs on blood agar plates, an estimate of total culturable bacteria, including pathogenic and non-pathogenic bacteria. In contrast, there was a decrease in the growth of bacteria from the oral cavity of the "in-season" athletes, when the growth of bacteria on mitis salivarius agar (primarily oral streptococcus) was measured (p=0.0006, Wilcoxon Rank Sum test). There was a negative correlation (Spearman Rank correlation coefficient=-0.651, p=0.0018 one-sided) between high IgA levels and the growth of bacteria on mitis salivarius agar in the combined group of "in-season" and "off-season" athletes, suggesting a protective response of high IgA levels to the typical oral pathogenic bacteria. Anxiety levels (GAD-7) in the "in-season" group were positively correlated with growth of oral bacteria on blood agar (Spearman Rank correlation coefficient of 0.622 for "in-season", p value=0.033 one-sided) and mitis salivarius agar (Spearman Rank correlation coefficient=0.671 for "in-season, p value=0.021 one-sided), and negatively correlated in "off-season" athletes on blood agar (-0.689 for "off-season", p value=0.028 one-sided), supporting the hypothesis that the microbiota are distinct in "in-season" and "off-season" athletes and may be associated with anxiety levels. CONCLUSION: These findings are supportive of the hypothesis that participation in college level athletics has a positive effect on student-athlete health, specifically enhanced protective oral immunity, reduced anxiety, and alterations in oral microbial populations.
