The Study
?-Endorphin, adrenocorticotropic hormone, cortisol and catecholamines during aerobic and anaerobic exercise
This study watched how some people's body chemicals changed when they exercised hard. It found that when they exercised more, some chemicals went up—and those chemicals often went up together. But it didn't prove that one thing caused the other, just that they happened at the same time.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
When you push your body past its limit during a long run, your body releases natural painkillers and stress hormones.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 526 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1This suggests the 'runner's high' is triggered by metabolic stress, not just effort — you need to push past your aerobic limit to feel it.
- 2After long exercise, β-endorphin and ACTH doubled; cortisol rose only after long exercise; β-endorphin rose with lactate (r = 0.63–0.71); adrenaline and β-endorphin rose together during short bursts (r = 0.65).
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
European Journal of Applied Physiology and Occupational Physiology
Year
1990
Authors
Lothar Schwarz, Wilfried Kindermann
Related Content
Claims (6)
Higher intensity aerobic exercise is associated with higher levels of cortisol in the blood after exercise.
During both aerobic and anaerobic exercise in healthy young adults, levels of β-endorphin and adrenocorticotropic hormone rise together in a coordinated manner, with consistent positive correlations observed across all time points.
In healthy young adults, β-endorphin levels rise during aerobic exercise only when the intensity exceeds the point where the body can no longer rely solely on oxygen for energy, and this metabolic stress triggers the release of endogenous opioids.
In healthy young adults, short bursts of intense cycling cause simultaneous increases in β-endorphin and adrenaline levels, and these two hormones rise together in a predictable pattern.
During intense aerobic exercise that pushes beyond the anaerobic threshold, β-endorphin and adrenocorticotropic hormone levels double compared to short bursts of anaerobic cycling, and these hormone increases are strongly linked to the highest levels of lactate produced in the blood.
After prolonged aerobic exercise, cortisol levels rise significantly in healthy young adults, but after one minute of anaerobic cycling, cortisol levels do not rise significantly.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.