Stress & Cortisol – Part I

Performance Killer – Walking the Razor’s Edge of Intense Training, Stress & Cortisol

By: Dr Tom Deters and Joe Mullings

We all know about stress – stress is the reaction to a stimulus which creates a response. If the stimulus doesn’t elicit a response, there is no stress.

Stress is NOT a dirty word – A certain level of stress is good / healthy as it stimulates a healthy or positive response. For example, the stress of a workout can stimulate muscle strength or growth.

Too much stress however, be it physical (over training in BJJ or MMA), mental (prolonged periods of intense thought or testing) , emotional (eg. financial, relationship problems, etc.) leads to a physiological cascade of hormonal and neurological responses that are NOT good for your overall health and can DEVASTATE your physical performance capabilities (strength and endurance) on the mat. Stress is a fact of life for an athlete, but how you manage it is critical.


There are two major hormones involved in the stress response: adrenaline and cortisol, both of which are produced by the adrenal glands (which are about the size of the tip of your thumb and sit on top of your kidneys). These are commonly referred to as the “fight or flight” hormones. These hormones have amazing and very pervasive effects on all your body’s systems.

Everyone has a different tolerance for various stimuli – some get an adrenaline / cortisol dump from a bad phone call from their manager, others from too grueling a workout, others from the anxiety of stepping on the mat in a tournament or in a cage. One important note is that unless you are taking preventative / adaptive measures, the more exposed to stress you are, often times the MORE you tend to react to it! In other words the same stress that caused a 1x response, over repeated exposures, could now stimulate a 2x response. This is not good news for a fighter enduring an intense training camp over 8-10 weeks leading up to an event.

The issue here is more the response to the stimuli, than the stimuli itself – and that means in simple terms, looking at how your body’s reaction affects cortisol levels.

Think of cortisol as the master stress hormone – even more so than adrenalin. Cortisol affects your entire hormonal and metabolic balance. Cortisol decreases testosterone (both its anabolic and androgen activity), impacts thyroid hormones (decreasing their affect) and more. We will address the testosterone impact in a later article.


So in a typical camp, be it MMA or BJJ there are a number of simultaneous and severe stresses. Here are some examples:

8 to 10 weeks out from the event:

– the athlete has just substantially changed the load on his body, has gone from some training or no training to 2 a days…wrestling, striking and Jiu Jitsu
– the athlete is coming off of a less than optimal diet to a more strict diet, eliminating soft drinks, candy, alcohol
– the athlete is dealing with various stress in their personal life- with schedule changes and relationships being put on the back burner
– the athlete is learning “new skills” as the opponent he is fighting is often dominant in an aspect of the game that he himself is not…so the focus is on learning new techniques to create a more balanced game

6 to 8 weeks out from the event:

– all the above apply, plus….
– sparring sessions or “live sessions” increase their intensity and frequency
– the athlete at this point may be cutting weight and working on a 10 to 20% reduction in body weight as an end goal for eventual weigh-ins.

4 to 6 weeks out from the event:

– the athlete has all of the above plus…..
– the athlete is likely is dealing with some sort of injury in the camp and working around it
– the overall intensity and tempo of camp increases
– there is an increased focus on cardio-conditioning than during earlier stages

2 to 4 weeks out from the event:

– all the above stresses plus
– reduction in carb intake
– body being taxed from tough camps

last week before the event:

– the athlete must travel, sleep in strange bed, deal with pre-fight anxieties
– the athlete is often cutting up to 10% of bodyweight through dehydration techniques
– the athlete is reducing carbohydrate intake (to drop water) which reduces energy

The challenge with any training program is to walk the razor’s edge between maximum workout intensity (and all the variables that impact that in terms of modalities, duration, frequency, periodization etc.) without crossing over into the realm of “overtraining” which is counter-productive. It is a widely held belief that most fighters go into top tournaments or MMA fights overtrained – that is over stressed – to various degrees.

Some of the symptoms of overtraining / high cortisol levels are:

– Higher resting heart rate
– Depression, irritability and anxiety
– Decreased immune system function (more susceptible to colds, illness)
– Decrease in energy and enthusiasm
– Decrease in positive mental attitude – feeling overwhelmed
– Decrease in both anaerobic and aerobic performance
– Increase in muscle tissue breakdown
– Increase in fat storage
– Decrease in insulin sensitivity
– Slower recovery time
– Decreased connective tissue strength (increasing the risk of injuries and tears)
– Decrease in testosterone (decrease in libido, intracellular protein)


As an extreme example to better your understanding, even just one intense workout a week could lead to an “overtrained” state if the person was not sleeping much, ate like crap, wasn’t supplementing, or was going through a hostile personal situation be it with a wife, girlfriend, securing sponsors, etc… which impacted them emotionally as well as financially. Why? Because cortisol levels would be tearing down, working against and depleting all the positive stimuli of training and the athletes recuperative powers.

Athletes should be monitored constantly as workouts are not the only variable (as mentioned above) to raising cortisol levels. A bad break up in a relationship could now cause this week’s training to be too stressful as compared to last week’s training (which may not have had the emotional stress). Early morning resting pulse is a crude but valuable test, whereby upon waking, before getting out of bed (even to go to the bathroom) the resting pulse is taken. Athletes who are in high stress / overtrained mode can have an increase of 10 beats per minute above their normal range. Additionally and ideally, salivary cortisol testing (considered by many to be the Gold Standard) can be done intermittently throughout the training camp (taken four times per day) to monitor the stress levels of the athletes so that training can be more precisely modulated.

The point is that training stimuli, stress levels as well as sleep, nutrition, supplementation and lifestyle factors etc. must be looked at holistically (in their combined entirety) to determine where the line between maximum training stimulus and overtraining may be crossed.


If the stress / elevated cortisol levels exist for extended periods of time (months or years) the adrenal gland becomes overstimulated and can “burn out” or become exhausted, leading to a diseased state which requires medical attention, supplementation and lifestyle adjustments (low stress levels) so that the gland can “recuperate” and return to normal function. This is a very slow process and can take up to two years!


All of the following aspects should be considered in order to maximize positive training adaptations and minimize cortisol levels, thereby avoiding the “overtrained / under-recuperated” state:

Nutrition – the goal is to meet the momentary nutritional demands of your body!

  • anti-catabolic diet in terms of food choices, ratios of proteins, carbs and fats
  • Meal timing and frequency relative to specific events
  • Supplementation –
    1. to meet macro and micro nutrient timing demands (protein / carbs / aminos)
    2. food alone will not provide adequate nutrients
      1. food often digests more slowly and less completely
      2. foods are not good sources of essential nutrients such as vitamins, minerals and micronutrients
      3. supplements offer quick, easy and efficient ways of maximizing nutritional “windows of opportunity”
    3. anti-cortisol supplements can enhance the body’s tolerance and minimize the negative effects of cortisol

Sleep and rest –

  • Minimum of 8 hours – uninterrupted sleep
  • Naps when you can get them
  • Meditation, quite time (letting your mind rest)

Hormonal Support –

Cortisol impacts a wide variety of hormones and as such these hormones should be monitored. Even in a young healthy male, extreme stress can dramatically lower testosterone levels, thyroid function and insulin sensitivity. Nutritionally and/ or medically supporting these systems may be helpful.

Work Outs –

Workouts do decrease cortisol levels – up to a point. Extreme training increases cortisol levels. Monitor early morning resting pulse and become more in touch with how you feel mentally and physically. Keep a journal.

Lifestyle –

This is a tough one as it is more insidious and often more difficult to “fix”. The stress of life wears on us all- jobs, family life, responsibilities, finances, relationships etc. Learning to get a better handle on emotionally charged issues through any number of coping skills is invaluable.

So here you have the effect of “cortisol” on high end athletes as well as non-athletes. In our follow-up article, we will give you more specifics on the ways to “mute” thru nutrition, supplements, monitoring and managing stress that affect your cortisol levels.


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