The effects of exercise training on hypothalamic-pituitary-adrenal axis reactivity and autonomic response to acute stress-a randomized controlled study.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 33109273 · doi:10.1186/s13063-020-04803-3
What was done
Untrained, healthy individuals aged 20–50 years were randomized to a 6-month aerobic exercise intervention (n=48) or a control group (n=40). Cardiorespiratory fitness was evaluated via peak oxygen uptake and time-to-exhaustion tests. Physiological stress reactivity was assessed before and after the intervention using the Trier Social Stress Test, measuring adrenocorticotrophic hormone, cortisol, systolic and diastolic blood pressure, and heart rate.
What was found
Oxygen uptake and time-to-exhaustion increased significantly after the intervention while decreasing in controls. At follow-up, physiological responses to the stress test attenuated across all variables in both the exercise and control groups, with no statistically significant differences between groups. No correlation was found between the amount of exercise completed and stress reactivity. The abstract provides no exact numerical values, effect sizes, or p-values for the physiological stress markers.
Why it matters
This trial directly tests the cross-stressor adaptation hypothesis and finds that substantial improvements in aerobic fitness do not alter neuroendocrine or cardiovascular responses to laboratory-induced psychosocial stress in healthy adults.
Limits
The abstract reports no numerical values, variances, or effect sizes for the primary stress outcomes. Test-retest habituation to the Trier Social Stress Test occurred in both groups, potentially masking intervention effects. The study was limited to healthy adults aged 20–50 and may not generalize to populations with baseline stress-related dysregulation.
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