Cortisol, Training, and the 'Stress Bucket' Theory

Amongst the “household hormones”, few stand out more than cortisol. You may have heard doctors or health communicators refer to the hormone in the context of stress and, by definition, it is the “stress” hormone. However, there are some things to clarify and some myths to dispel when it comes to cortisol and exercise. This week, we will talk about how the brain doesn’t distinguish between a deadline at work and a heavy set of five, how chronic cortisol elevation affects you, and how we can monitor this in the gym. 

First, some definitions. “Allostasis” is the body's state of consistent adaptation to environmental stressors; our management of allostasis is what determines whether or not something is detrimental or positively influencing our bodies and minds. The accumulation of this chronic stress is called “allostatic load” and can be measured via cortisol, blood pressure, and a combination of inflammatory markers. Factors like poor diet, lack of sleep, low socioeconomic status, and major life events contribute to higher allostatic load. If you have ever heard the term “cortisol bucket” or “stress bucket” in the media, it is referring to this exact phenomenon. 

Chronic allostatic load can cause a number of detrimental health effects, from poor sleep quality and high blood pressure, to chronic illness and increased risk of injury. If managed well, however, the gym can actually positively affect chronic allostatic load by attenuating - or weaken - the effect of cortisol. So let’s talk more about what cortisol even is, and why its actually important despite its negative connotation: Cortisol is a vital steroid hormone that is secreted by adrenal glands in the body. This hormone is highest in the morning - cortisol is actually the “alarm clock” that wakes our body up - and lowest at night time when we are supposed to be winding down for sleep. Although the context of cortisol is often whether or not it is high, if it is too low you can experience “addison’s disease”, chronic fatigue and weakness. Cortisol is a “catabolic” hormone, which is responsible for the breakdown of larger molecules and structures in the body.

This sounds bad, but you need this to happen if you are to digest food, breakdown wasteful or degrading tissue, repair wounds, or otherwise. This stands to balance out the effect of “anabolic” hormones like testosterone and growth hormone. Herein lies where the imbalance is a problem: Too much cortisol means too much breakdown.

So what about exercise?

Exercise creates an acute (short term) spike in cortisol; the harder the workout the larger the spike. This is a temporary increase in allostatic load, and certainly too hard of a workout (referred to as overtraining) is a bad thing. We seek to avoid overtraining by monitoring your workout progress, repetition ranges, and overall load of movements so we are rarely going to run into states of overtraining in the gym. Additionally, when you expose the body to chronic, but manageable stress, the body learns to adapt and therefore attenuates the cortisol levels as mentioned before. Again, the body does not necessarily recognize the difference between a long day at work and a heavy squat, but when you consistently do heavy squats, you actually make your long day at work easier.

This transferability of fitness to daily life is why consistency in the gym is so important, and why you cannot stop once you start, and why consistency in periods of high stress are actually more critical to long term success - especially because we monitor your stress load ourselves, and seek to avoid overtraining. 

Overall, we should seek to maintain the intensity in the gym, as long as it matches what we can handle. In the long term, it does us better than avoiding days in the gym when we are already stressed. I say to my clients all the time: “I’d rather have you in at 2% than not at all” and that goes for all of us here at Method!