Biology of Stress – An overview of Cortisol and Allostasis

We’ve all experienced stress.  A little bit is great as you can attest to after you waited until the last minute to write that paper and it only took a minute because such a fire was lit under your ass…

But a lot of it is horrible.  Ask anyone that’s dealt with the chronic headaches, bad nights of sleep, and constant worries.  When you’re over stressed it can be hard to carry on with the rest of the world.

That constant stress is commonly associated with high levels of the hormone cortisol.  What’s worse is that even though the human body is a brilliant machine, it’s kind of slow to react, endocrinologically speaking.  So when the stressor is removed that heightened level of cortisol may remain leaving with it the generally feeling of being “stressed out.”

What is Cortisol?

Cortisol, commonly known as “the stress hormone,” is a glucocorticoid hormone released from the adrenal glands (which sit atop the kidneys for reference sake) (1). At optimal levels cortisol contributes to stabilized neuronal excitability (2),  maintenance of neuronal integrity (3), suppression of hypothalamic-pituitary-adrenal activity (4) and facilitation of behavior adaptation. Normally cortisol tends to remain at optimal levels through a circadian cycle, however outside stimuli may trigger release through the hypothalamic-pituitary-adrenal (HPA) axis (1).

Cortisol is the end result of a cascade of hormones working via the Hypothalamic-Pituitary-Adrenal (HPA) axis and is regulated by negative feedback (1). That is, as cortisol is released from the adrenal glands another hormone, adrenocorticotropic hormone (ACTH), is inhibited suppressing further output. This is a wonderfully simple system; the system is triggered and the final product is what eventually shuts the system down. However, when our cortisol levels remain spiked the sensitivity of the system is decreased leading to a greater concentration of cortisol in the body.

A more general way to say “chronically elevated cortisol,” clinically called “Allostatic Overload,” is to say “over stressed.” It is well known that stress isn’t all bad and we need to learn how to maximize its positive effects while decreasing its negative effects. Feelings of stress have strong correlation to some hormonal underpinnings and by identifying and defining the problem at a physiological level we can develop a greater understanding of the system, it’s benefits and how to maintain allostasis (homeostasis of stress responses).

There is no better example of allostatic overload than sleep deprivation; cortisol is elevated, blood pressure is elevated, there is reduced parasympathetic activity and an increased hunger for comfort foods due to the hormone ghrelin (3).  When considering this extreme example it’s easy to associate over eating, low sex drive, bad memory, depression and anxiety with elevated cortisol; these are things we typically associate with someone that hasn’t slept well in days.  Balancing allostatic load means stepping away from that extreme to mitigate the deleterious effects.

Balancing Allostatic load


Sleep doesn’t just decrease cortisol levels, it optimizes them. When you gets restful night of sleep your morning cortisol levels are actually  elevated (5) and this is a good thing.  This is that heightened awareness we hear “morning people” going on about. Subjects experiencing sleep deprivation are likely to have decreased morning cortisol but increased evening levels (5). This leads to overtired and exhausted mornings and frustrating nights.

As you may have intuitively surmised from the former paragraph, the first step in reducing levels of cortisol is getting more sleep.  Getting more sleep is that simple-in-theory and nearly impossible in execution aspect of life that never seems to go away.  This is typically because we are in front of stimulating screens most of the day and suddenly we try to lay down in a dark room and go to sleep.  You can begin to condition yourself to sleep easier by utilizing environmental cues and reward systems to create a ritual that you perform before lying down to sleep.  The more consistent you remain with this ritual then more effective it will become.
Alcohol and Caffeine

In addition to sleeping more cutting back on substances like caffeine and alcohol is one of those things you knew before you came here to read is article, nonetheless we’re still going to cover it. Caffeine is a stimulant and alcohol is a depressive, while these two may not be your poison the  guidelines laid out below are good to follow for anything in those two categories.  Both caffeine and alcohol will increase allostatic overload when taken too close to going to sleep and when overconsumed.

In one study participants were randomly dosed with varying amounts of caffeine prior to resistance exercise (6). Cortisol output rose linearly with caffine consumption with an 800mg dose of caffeine resulting in a whopping 52% increase in cortisol levels.

The Mayo Clinic recommends not exceeding 500-600 mg of caffeine a day and according to the half life of caffeine may be about 6 hours.  With regards to caffeine try to keep consumption under 250-300 mg a day, there may be stressful times when you find yourself consuming more.  This is fine, just do not allow it to become the new normal, try to keep caffeine consumption in check and do not imbibe caffeine 6-8 hours before your planned bed time.

Alcohol, like smoking, is associated with a large array of stress related issues even though it can give the user some level of relaxation, again like smoking.  While I do believe alcohol in low doses can alleviate stress effectively I’d like to address some guidelines for not going over the threshold and turning it into a source of stress:

This is the most perfect moment for a beer


  • Don’t drink every night (If you’ve had a drink the last two nights, then skip it)
  • Stop at least 2 hours before you plan to go to bed (Alcohol inhibits vasopressin, a key component in memory and dreaming)
  • Drink for quality, not quantity (enjoy what you drink, don’t just drink a lot)

Behavioral Changes

Lastly, I want to address the methods of decreasing allostatic overload that may become overlooked because they may seem somewhat “New-age” or “Hippy Dippy.”  Despite this initial appearance I encourage you to read on and try to apply each of these methods.

The first is to become more present in what you are doing; multitasking can quickly turn into visual and auditory inundation.  For instance over the course of writing this article I found myself frequently stopping because I felt stressed (ironic, right?) but then I did something simple: I turned my music off.  Even though it was instrumental and supposedly would help me focus, turning off all outside noise had the most benefit of my productivity and my perceived levels of stress.

When becoming more present in what you’re doing you may find that meditation helps.  While I do try to engage in meditation, I don’t feel as though I’m in a position to give advice.  If you’re interested in meditation check out Tara Brach.  Another thing I’ve come across designed to stimulate mindfulness is the 21-Day No Complaint Challenge.

Trying to be more social and this doesn’t have to be in the classical sense of talking to more people (introverts rejoice!).  It can be as simple as purposefully engaging playtime with a pet, meeting people in an online game, being more mindful and present in conversation with your significant other or as standard as meeting friends from work for dinner and drinks.  The more we interact with the beings around us, humans or animals, the more we feel ourselves as part of a supported network which will in turn alleviate our stress.

 Lastly I want to end this article with a recommendation of being more creative.  Whatever your chosen medium; painting, music, comedy or cooking, putting your emotions into something you create will never cease to decrease the stress from life.  I’m going to end this article with a video of Neil Gaiman giving a commencement speech entitled “Make Good Art.”  Watch it, be mindful of it, share it with your friends, make art and be well.

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1. Marta Gonzalez-Alvarez, Victor Mangas-Sanjuan, Carmen Navarro-Fontestad, Isabel Gonzalez-Alvarez & Marival Bermejo. Cortisol Transport Across Biological Barriers. Cortisol : Physiology, Regulation and Health Implications. 2012.

2. Joels M, de Kloet ER.  Mineralocorticoid and glucocorticoid receptors in the brain.  Implications for ion permeability and transmitter systems.  Progress in Neurobiology. 1994.

3. Bruce S. McEwen. Central effects of stress hormones in health and disease: understanding the protective and damaging effects of stress and stress mediators. European Journal of Pharmacology. 2008.

4. Dallman, et. al. Stress, Feedback and Facilitation in the hypothalamio-Pituitary-Adrenal Axis.  Journal of Neuroendocrinology. 1992.

5. Eek, Frida, et al. Psychoneuroendocrinology: Cortisol, Sleep, and Recovery – some Gender Differences but no Straight Associations. 37 Vol. Elsevier, 01/01/2012. Web. 21 Dec. 2015.

6. BEAVEN, CM; et al. Dose Effect of Caffeine on Testosterone and Cortisol Responses to Resistance Exercise. International Journal of Sport Nutrition & Exercise Metabolism. 18, 2, 131-141, Apr. 2008.