The Study
Acute Effects of 24-h Sleep Deprivation on Salivary Cortisol and Testosterone Concentrations and Testosterone to Cortisol Ratio Following Supplementation with Caffeine or Placebo
This study tried to see if caffeine helps athletes’ hormones when they haven’t slept, but it only tested 9 people. It didn’t prove caffeine does anything for sure — it just showed a little hint that maybe it helps. So we can’t say caffeine fixes the problem, but it might be worth testing again with more people.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study tested if drinking a strong coffee before a tough workout helps athletes who didn't sleep the night before keep their energy and hormones balanced.
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 548 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Even though caffeine helped hormones a little, the overall balance between muscle-building and stress hormones got worse — meaning the body was still under more stress than when well-rested.
- 2Caffeine made cortisol (stress hormone) rise less and testosterone (muscle hormone) drop less after exercise in sleep-deprived athletes, but didn't make them run faster or farther.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
International Journal of Exercise Science
Year
2017
Authors
C. M. Donald, Joss Moore, Alan McIntyre, Kevin Carmody, B. Donne
Related Content
Claims (6)
In competitive male athletes, staying awake for 24 hours does not change salivary testosterone or cortisol levels during aerobic exercise. Taking 6 mg of caffeine per kilogram of body weight reduces the increase in cortisol and lessens the drop in testosterone after exercise.
In competitive male athletes, 24 hours without sleep does not lower testosterone levels in saliva during aerobic exercise.
When athletes exercise intensely after going 24 hours without sleep, their stress hormone levels rise more than when they are well-rested, showing that lack of sleep makes the body react more strongly to physical stress.
Even though caffeine may slightly reduce stress hormones and help maintain testosterone during sleep loss, the overall balance between muscle-building and stress hormones is still worse than when athletes get enough sleep.
Taking 6 mg of caffeine per kilogram of body weight does not help athletes perform better in short, intense aerobic tests after going 24 hours without sleep.
Cortisol levels raised by caffeine, poor sleep, and screen exposure are associated with higher anxiety, worse sleep, more abdominal fat, and lower testosterone in humans.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.