Testosterone to Cortisol - the all important ratio

Doctor Daniel Grant explains why knowing the testosterone to cortisol ratio (T:C) marker could optimise training and performance for elite athletes who track and trend their blood results.

What is the testosterone to cortisol ratio?

The testosterone to cortisol (T:C) ratio is a good measure of whether elite athletes are recovering from their training. This marker is quite sensitive and is only relevant for high-level endurance athletes or strength trainers who track and trend their blood results. So what's so important about this ratio?

Testosterone is an anabolic hormone – it helps to build muscle, produce red blood cells and increase aerobic metabolism in muscles. Cortisol is a catabolic hormone – it works antagonistically with testosterone, inhibiting protein synthesis and blocking anabolic signalling.

When chronically elevated, cortisol actively breaks muscle down and makes you more prone to infection. For both endurance and strength trainer athletes, the T:C ratio provides a useful marker of possible overreaching and overtraining syndromes, which is where the body does not sufficiently recover after exercise. This in turn can lead to a decline in performance, physiological stress, and emotional change.

Know when to stop

The T:C ratio is more sensitive to the stresses of training than either testosterone or cortisol measures alone. As an absolute number, the ratio is of limited use, but over time it can be trended to see how well you are recovering and indeed the true value of the T:C ratio is seen when these trends start to appear.

A 30% decrease in T:C ratio has been suggested as an indicator of insufficient recovery and can point towards overtraining (though it is not a diagnosis in itself). If this is the case for you, then it is extremely important to reflect on your training routine and make sure you recover sufficiently to prevent long-term ill-health.

Athletes with decreasing T:C ratios should talk with their coaches to:

- Review their performance diaries/results.

- Be open and honest about how they feel both before, during and after an intense training session or event.

If an athlete succumbs to overtraining syndrome, it can take weeks to months to recover – so you can see the value in spotting it early.

This test is most useful for male athletes as testosterone levels are higher and at a level where the ratio can be viewed with clarity. Women have far lower levels of testosterone than men and so it’s very difficult to see changes in the ratio in a statistically relevant way. Women who are struggling with performance can monitor both their hormones and nutrient levels and discuss these findings with their coaches.

Check your performance with Medichecks

We aim to make blood tests accessible to anyone who wants to improve their performance.

To do so, we are constantly reviewing our range of sports tests to see how we can improve what we offer, and to provide the best range of tests for athletes of every level and discipline to optimise their performance and stay healthy.

Our Testosterone and Cortisol Blood Test is useful if you are looking to check the balance between your training and recovery.

A T:C ratio has also been added to many of our sports profiles including the Endurance Fitness Blood TestAdvanced Fitness Blood Test and Advanced Sports Hormone Blood Test to help assess whether the body is recovering well after intense training.

For both endurance and strength training athletes, the T:C ratio provides a useful marker of possible overreaching and overtraining syndromes - where the body does not sufficiently recover after exercise.


- Open Sport Sciences Journal - US National Library of Medicine National Institutes of Health

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