Cortisol - the hormone of alarm

Doing something that is productive is a great way to alleviate emotional stress. Get your mind doing something that is productive.” – Ziggy Marley

Thank you for joining me for blog 27 highlighting decision-making and the brain. This is my public exploration of what drives decision-making and how we can use that information to make better decisions, resulting in better outcomes.

Today's blog is about stress hormones and cortisol in particular. This is a truly fascinating not only for the impact on our decision-making, but also how chronic stress which seems to be all-too-common, is damaging not only our mental health, but our physical health too.

What is Cortisol and how is it triggered?

Cortisol is essential to our survival. It is released by the adrenal glands when it gets a message that there is a threat present. Perceived danger can be something obviously life-threatening like being severely underfed, hearing the roar of a lion, the screaming of someone being attacked. Cortisol is also triggered by social dangers, like social exclusion (being ignored or ostracised), a drop in social status or ending a romantic relationship.

The immediate effect of a spike in cortisol is like an alarm. It draws all your attention to the perceived threat and gives you the feel that an awful thing will happen unless you ‘do something’. A surge in cortisol could depending on the environment make you more aggressive or prepared to act in self-defence (depending on whether you think you are stronger or weaker than your competition). Cortisol encourages a mother guard her child.

Cortisol and the brain

Cortisol is more than just a spur to immediate action. Cortisol acts very broadly and has a number of impacts. Cortisol promotes memory formation, so we tend to remember instances where we had a large spike in cortisol. If you had a close brush with a lion, and the next week see fresh lion dung, the association between that and the previous spike in cortisol will cause another spike. The interaction between the brain and cortisol has caused an association so you will feel awful until you are safe. In short, cortisol encourages course correction when in a potentially dangerous situation.

Cortisol does however, hinder memory recall. In normal times we would easily be able to remember something, but the chaotic or hostile environment makes it much more difficult. This is because cortisol (and adrenaline which would normally be released too) has the effect of preventing subsequent memory formation after an event. It is not unusual for people to remember everything up until their accident, but have a blank for the moments afterwards.

Everyday Cortisol spikes

Nature has generally rewarded caution so you are much more likely to release cortisol unnecessarily, than you are likely to face danger without releasing cortisol. We have evolved to be survival machines rather than happiness machines.

In today’s relatively safe environment, we are less likely to experience life-threatening danger or famine and our sources of cortisol spikes are for more trivial reasons - but the cortisol impact is real. Today cortisol is released about the fear of missing deadlines, a feeling of lagging behind your competitors or not getting recognised for how hard you work. It is about disappointment of not winning the contract you have worked so hard to win or not getting the job that you thought you were perfect for.

If a large spike in cortisol to face a life-threatening danger equates to a feeling of fear, a more moderate dose feels like stress or anxiety. Stress seems to give people a sense of overwhelm or panic. This is clearly not the mindset you want, when making big decisions.

An example of how this might lead to poor decision making is taking the example of internet scammers. Many internet scammers employ a tactic that tells people they are about to lose the money in their bank account or have their files compromised. The cortisol spike on hearing about that makes them do something they would not otherwise do, for example hand over sensitive passwords to someone they do not know. Stress seems to significantly decrease the quality of people’s judgment.


Given cortisol is critical in memory formation and associations, it is not too much of a stretch to see how soldiers who have served in warzones might come back with many triggers to cortisol. Some people report than sounds or smells or seeing specific objects are sufficient to trigger a huge spike in cortisol. These triggers are tough to moderate but recent advances in understanding how the brain and cortisol interacts has led to some promising advances in moderating the impacts of PTSD.

Long term impact of too much cortisol

A spike in Cortisol leads to elevated sugars in the bloodstream, and curbs functions that would be nonessential or harmful in a fight-or-flight situation like the immune, digestive, reproductive and growth systems. In other words it’s as if cortisol suppresses the non-essential long-term working of your body focusing all your resources to avert a crisis. Whilst this is occasionally fine, chronic stress has significant long-term consequences.

The impact of long term elevated cortisol includes:

1) diabetes and weight gain

2) anxiety and depression

3) sleep problems - high cortisol is associated with insomnia

4) digestive problems

5) weak muscles and bones

6) memory and concentration issues

7) increases the rate of heart disease.

Yes, that is the price of not managing your stress. A bonus negative is that stress draws from your cognitive bandwidth, and thus you are more likely to give into bad habits that provide a temporary perk like unhealthy food, alcohol, shopping, drugs, seeking approval, escaping, thrill-seeking. You are also more likely to get angry or otherwise find it difficult to control your emotions.

How can I manage a cortisol surge

1) Respond not react: the alarmed feeling that people get with cortisol, feels very uncomfortable. By resisting the immediate need to react by shooting off an email or having an angry conversation you will be better off. It is better to respond once the cortisol wears off and you can engage higher order thinking. This prevents a vicious spiral which would add regret to your list of concerns

2) Let cortisol wear off before making a decision: I find walking a great way for the surge in cortisol to pass. Meditating or deep breathing also helps to extract you from the threat-focus that cortisol creates

3) Do something that is productive in a non-taxing way: paying bills or ticking off a few essential but mechanical items on your to-do list is a good way to distract yourself from your cortisol trigger

4) Activate happy chemicals: Activating happy chemicals in a way e.g. exercise, stretching or meeting a friend is a good way to flood positive vibes to dilute that alarmed feeling.

Long-term however, just trying to manage the surge will not be sufficient. Identifying and moderating your key stress triggers like relationships, work environment or other factors and practicing ways to think that turns these 'threats' into 'challenges' that you can overcome. It does seem to me, that above and beyond all of these, a long-term valued goal that you are making progress towards is the best way to keep your mind focused away from many of the trivial spikes in cortisol (e.g. computer crashing, perceived slight, feeling of others making more progress).

So what?

How is this all relevant to decision-making? Here are three take-aways I want to leave you with before we pick it up next week:

1) A surge of cortisol causes a sense of alarm triggered by a perceived threat. It results in a feeling that you need to just ‘do something’. That urge to act means that decisions made with elevated cortisol might not be well thought through.

2) We sometimes feel moderately elevated levels of cortisol as stress or anxiety that could be triggered by social threats. Cortisol shifts the body’s resources to averting crisis rather than maintenance and therefore long-term elevated cortisol results in physical and mental health problems.

3) Our best response to cortisol is to resist the urge to carry out a poorly thought through action and then try and regain focus and composure to act if necessary.

Thank you for joining. Next week we will cover 'The role of other hormones in decision-making'.