The short version
- A 2017 systematic review of 38 studies found basal hormone levels were mostly normal in athletes with overreaching or overtraining syndrome, and concluded resting hormone levels are not a good predictor.
- The 2013 ECSS and ACSM consensus statement on overtraining says none of the available markers meet all the criteria to make their use generally accepted.
- Across 56 studies, athletes' own subjective wellbeing ratings tracked acute and chronic training load with better sensitivity and consistency than objective measures such as blood markers and heart rate.
- A 2020 meta-analysis of four trials in 142 people found a statistically significant improvement in VO2max with ashwagandha (mean difference 3.00, 95% CI 0.18 to 5.82) with high heterogeneity.
- A 2024 systematic review screened 1,254 articles on magnesium and muscle soreness and found only four that met its eligibility criteria.
The message arrives about once a month, in slightly different words each time. Training has gone flat. Sleep is worse. Everything aches a bit longer than it used to. Should I get my cortisol tested?
Almost always, no — and the reason is more useful than the answer.
The vocabulary does real work here
The 2013 joint consensus statement from the European College of Sport Science and the American College of Sports Medicine opens by pointing out that successful training must involve overload, and must avoid the combination of excessive overload plus inadequate recovery. Those are two different requirements and people usually only hear the first.
It then separates three states. Functional overreaching is a short-term performance dip that resolves into improvement once you recover — that is training working as designed. Non-functional overreaching is what happens when the balance is not respected. Overtraining syndrome is described as prolonged maladaptation. The consensus is candid that telling the last two apart is very difficult and depends on clinical outcome and exclusion diagnosis, and that while overtraining syndrome is generally assumed to be more severe, there is no scientific evidence to confirm or refute that.
And then the sentence that should end most cortisol conversations. Several categories of marker are in use — hormones, performance tests, psychological tests, biochemical and immune markers — and, in the consensus authors' words, none of them meet all the criteria to make their use generally accepted.
What a hormone panel actually shows in an under-recovered athlete
Cadegiani and Kater went looking specifically for this. Their 2017 systematic review in BMC Sports Science, Medicine and Rehabilitation pulled 38 studies covering every hormone people associate with overtraining — cortisol, ACTH, growth hormone, testosterone, IGF-1, thyroid hormones, prolactin and more.
Basal hormone levels were mostly normal in athletes with overtraining syndrome or overreaching compared with healthy athletes. Cortisol and catecholamines produced conflicting findings across studies. What did separate the groups was stimulation testing under maximal exercise conditions, where blunted growth hormone and ACTH responses showed up. The authors' conclusion is one sentence long: basal hormone levels are not a good predictor.
Read that against the product you were about to buy. The resting cortisol you can order online is precisely the measure that did not work. The measure that did is a provocation test in a lab.
The monitoring tool that beat the blood test
Saw, Main and Gastin reviewed 56 studies in the British Journal of Sports Medicine that reported subjective and objective measures of athlete wellbeing side by side. The headline is in the title: subjective self-reported measures trump commonly used objective ones.
The two categories generally did not correlate with each other. Subjective measures tracked both acute and chronic training load with better sensitivity and consistency than blood markers, heart rate or oxygen consumption. Subjective wellbeing dropped with an acute increase in load and with chronic training, and recovered when load came down.
The best-performing instrument in that literature is athletes writing down how they feel. It costs nothing, works daily rather than quarterly, and no one sells it.
So where do adaptogens honestly fit?
Cleanly, and narrowly. Ashwagandha's evidence base is about the physiology of psychological stress — we have written separately about what the dose needs to be and what the male hormone data does and does not show, and we are not going to relitigate either here. The question in this article is different: can anything increase how much training you are able to absorb?
The nearest thing to a pooled answer is a 2020 meta-analysis in Nutrients on ashwagandha and VO2max. Five studies in the review, four in the meta-analysis, 142 participants. There was a statistically significant improvement (mean difference 3.00, 95% CI 0.18 to 5.82, p = 0.04), with high heterogeneity between studies, and the authors' own conclusion asks for more research because the number of studies is limited. Four studies with a confidence interval that nearly touches zero is a signal worth watching, not a protocol.
Magnesium sits in a similar place. A 2024 systematic review in the Journal of Translational Medicine screened 1,254 articles on magnesium and muscle soreness and found four that met eligibility. Those four reported reduced soreness, better recovery and a protective effect on muscle damage; the authors suggest people training intensely may need 10 to 20% more magnesium than sedentary people. We sell magnesium, and we are telling you the review behind that claim contains four studies.
What we'd actually tell you
The first intervention is a deload, and it is free. If a week of reduced volume restores your training, you were functionally overreached and the system worked. If it does not, you have learned something a cortisol test would not have told you.
Second, start writing down a daily number. Sleep, soreness, motivation, mood — one to ten, thirty seconds. On the evidence above, that is a better early-warning system than anything you can order.
Third, rule out the boring causes before the interesting ones. The consensus statement's own approach starts by excluding organic disease and infection, then factors like negative energy balance, insufficient carbohydrate or protein, iron deficiency and magnesium deficiency. If you are going to spend money on a test, spend it on bloods ordered by a clinician who knows your history.
Supplements come fourth, and honestly labelled. Ashwagandha for the stress side of a hard stretch. Magnesium if your intake is genuinely low. Neither of them buys you the recovery capacity that a lighter week buys you for nothing.
Good questions
Should I get my cortisol tested if my training has gone flat?
Usually not. A systematic review of 38 studies found resting hormone levels, cortisol included, were mostly normal in athletes who were genuinely overreached, and concluded basal levels are not a good predictor. The tests that did separate groups were lab provocation tests. If you want to spend money on a test, ask a clinician for bloods that rule out the common causes of fatigue.
How do I know if I am overtrained or just tired?
Take a lighter week and see what happens. A short-term performance dip that resolves into improvement after recovery is functional overreaching, which is training working. Sports medicine's own consensus says distinguishing the more serious states is very difficult and depends on clinical assessment and ruling other things out. A deload is the cheapest diagnostic you have.
Does ashwagandha help you recover from training?
The honest answer is that nobody has shown it increases how much training you can absorb. The closest pooled evidence is a meta-analysis of four trials showing a small improvement in VO2max with wide uncertainty and high heterogeneity. Ashwagandha's stronger file is the psychological stress side. If you are under-recovered because your training load is too high, it will not fix that.
Is magnesium worth taking if I train hard?
Possibly, if your intake is low, but the evidence is thin. A 2024 systematic review searched three databases for magnesium and muscle soreness and found four eligible studies. Those four were positive and the authors suggested intense training raises requirements by 10 to 20%. Four studies is a hypothesis. We sell magnesium and we would rather you knew that number.
Can I supplement my way out of under-recovering?
No. Under-recovery is an arithmetic problem between the load you are adding and the recovery you are allowing, and no capsule changes either side of that. A deload week is free and works. Supplements can support the stress and nutrient side of a demanding stretch, but treating them as a substitute for reducing load is how people spend six months feeling flat.
What is the cheapest way to track whether I am recovering?
Rate sleep, soreness, motivation and mood out of ten each morning and write it down. In a review of 56 studies, these subjective measures reflected both acute and chronic training load with better sensitivity than objective markers, and the two categories generally did not correlate. It takes thirty seconds a day and outperforms most of what you could buy.
Sources
- Meeusen R, Duclos M, Foster C, et al. Prevention, diagnosis, and treatment of the overtraining syndrome: joint consensus statement of the European College of Sport Science and the American College of Sports Medicine. Med Sci Sports Exerc, 2013. View study
- Cadegiani FA, Kater CE. Hormonal aspects of overtraining syndrome: a systematic review. BMC Sports Sci Med Rehabil, 2017. View study
- Saw AE, Main LC, Gastin PB. Monitoring the athlete training response: subjective self-reported measures trump commonly used objective measures: a systematic review. Br J Sports Med, 2016. View study
- Pérez-Gómez J, Villafaina S, Adsuar JC, Merellano-Navarro E, Collado-Mateo D. Effects of Ashwagandha (Withania somnifera) on VO2max: A Systematic Review and Meta-Analysis. Nutrients, 2020. View study
- Tarsitano MG, Quinzi F, Folino K, et al. Effects of magnesium supplementation on muscle soreness in different type of physical activities: a systematic review. J Transl Med, 2024. View study
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
