Research
Hormonal
Salivary testosterone and cortisol ratios are inconsistent predictors of strength performance and are not practical for regular training regulation due to high variability between individuals and lack of immediate utility.
Do not rely on blood or saliva tests for daily training decisions. They are expensive, invasive, and inconsistent. Instead, use performance metrics like barbell speed or how hard the set felt (RPE) to guide your training.
GoodRefutesHIGH confidence
Overall, there appears to be a high level of variability and inconsistency regarding the use of pre and post workout levels of, changes in, and the ratio between testosterone and cortisol as a predictive tool to monitor and regulate performance.
Why this rating
Based on review of multiple studies showing conflicting results.
Source
Methods for Regulating and Monitoring Resistance Training
Eric R. Helms et al. · Journal of Human Kinetics · 2020
DOI 10.2478/hukin-2020-0011
narrative_reviewCited 41×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Barbell velocity and Reps in Reserve (RIR) based RPE are practical, reliable, and strongly correlated with resistance training performance, making them superior tools for autoregulating load and volume.Strong
- Autoregulated resistance training using performance-based metrics (velocity, RIR, or RPE) optimizes adaptation by matching training stress to individual daily readiness and recovery, thereby reducing overtraining risk compared to fixed-load prescriptions.Good
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