Salivary cortisol and α-amylase responses to repeated bouts of downhill running

Andrew J. Mckune, Christopher W. Bach, Stuart J. Semple, Barry J. Dyer

    Research output: Contribution to journalArticle

    11 Citations (Scopus)

    Abstract

    OBJECTIVES: To determine the hypothalamic-pituitary-adrenal (HPA) axis and sympathoadrenal (SA) system response to repeated bouts of downhill running.

    METHODS: Eleven active but untrained males (age: 19.7 ± 0.4 y; VO2peak 47.8 ± 3.6 ml/kg/min) performed two 60 min bouts of downhill running (-13.5% gradient), separated by 14 days, at a speed eliciting 75% of their VO2peak on a level grade. Saliva samples were collected before (baseline), after, and every hour for 12 h and every 24 h for 6 days after each run. Salivary cortisol and α-amylase levels were measured as markers of the HPA axis and SA response, respectively. Results were analyzed using repeated measures ANOVA (12 h period: 2 × 14; 24 h intervals 2 × 7, P ≤ 0.05) with Tukey post-hoc tests where appropriate. Paired samples t-tests were used to compare collapsed data vs. baseline measurements.

    RESULTS: There were no significant group × time interactions for cortisol or α-amylase for the hourly samples up to 12 h after each run, nor for the 24 h samples up to 6 days later. The 24 h samples for α-amylase showed a significant group effect between runs (Run 1: 69.77 ± 7.68 vs. Run 2: 92.19 ± 7.67 U/ml; P = 0.04). Significant time effects were measured for both cortisol (decreased 2 h to 12 h post-run) and α-amylase (elevated immediately after, 1 h and 2 h post-run) (P < 0.001).

    CONCLUSION: The 24 h period group effect for salivary α-amylase suggested an adaptation in the sympathoadrenal system that may alter the systemic inflammatory response to exercise-induced muscle damage but may also reflect enhanced mucosal immunity.

    Original languageEnglish
    Pages (from-to)850-855
    Number of pages6
    JournalAmerican journal of human biology : the official journal of the Human Biology Council
    Volume26
    Issue number6
    DOIs
    Publication statusPublished - 1 Nov 2014

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