An Introduction to Cortisol

The primary stress hormones, cortisol and adrenaline (aka epinephrine) are produced by the adrenal glands in response to the brain perceiving danger and signalling (via the autonomic nervous system) that certain physiological responses need to happen immediately in order for us to survive an emergency situation. Cortisol and adrenaline have multiple uses within the body and both have complicated interactions with other hormones. But my interest is in how we experience them in terms of energy, anxiety and cravings.

Cortisol is often overlooked in favour of the better known adrenaline. But whereas adrenaline is a fast acting hormone supplying your limbs and heart with extra oxygen to allow you to fight or flight from a threat, the mechanism involved with cortisol has a slower but longer lasting hormonal response.

Cortisol helps to raise the amount of glucose (sugar) in the bloodstream. This increases the amount of energy that is immediately available to us.

Two benefits of cortisol expression are to (1) help wake us up in the morning and (2) support adrenaline’s fight or flight response. Unfortunately, modern living tends to send most people’s cortisol production out of balance so that their levels are too high, too low or highly erratic. The knock on effect to health is often complicated but this guide is designed as a basic introduction.

Cortisol’s 24 hour cycle

  • Your level of cortisol production should peak every morning at around 8am. High cortisol in the morning means that you have enough glucose in your bloodstream to Get up! Get out! and Go hunt!
  • During the day your food intake, sunlight exposure and activity levels should help regulate your energy levels and so your cortisol production can begin to slow down so that it is at its lowest in the evening.
  • During the night your cortisol production gradually increases so that by day-break you are good to go again.

Cortisol’s emergency function

You remember that cortisol’s primary function is to increase glucose? Well, in response to a threat (either real or imagined), while adrenaline is signalling your heart to beat faster and your blood vessels to contract for that all important oxygen, boost, cortisol will increase your blood glucose levels so that you can run further or fight for longer. Blood glucose is a source of immediate energy.

Cortisol imbalance

The problem is that our entire hormonal system needs to be carefully balanced throughout the day. If your cortisol level is triggered to stay too high for too long and at the wrong times of day then it upsets the delicate balance of fifty or so other hormones and of numerous neurotransmitters.

At a physical level, high cortisol production detracts from non-emergency processes such as

  • Wound healing
  • Muscle and bone formation and maintenance
  • A healthy menstrual cycle, reproduction and libido
  • Immunity
  • Thyroid hormone production and transformation
  • Digestion
  • Melatonin production – which can interfere with sleep.

Cortisol can also upset the role of non-emergency neurological processes and so impair:

  • Short term memory
  • Mood regulation
  • Behaviour regulation
  • Planning and organising (our executive functions)
  • Making good judgements.

You may recognise yourself as having some of these temporary brain impairments in situations that you find stressful.

How food affects your cortisol balance

If you’ve ever had a “sugar crash” a little while after consuming too much sugar, alcohol or even just too many carbs in one go you may well notice some of the problems I listed above. Maybe you forgot where you left your keys, you felt like you wanted to cry, you yelled unnecessarily at someone, you couldn’t decide what to pack or cook, or you did something impulsive that you’ll regret later.

When you eat carbohydrates (such as sugar, bread, pasta and potatoes), your digestion quickly breaks them down into simple glucose molecules . These are absorbed into your bloodstream to be transported around the body for immediate energy. However, your bloodstream should only ever have around 4g of glucose (sugar) in your bloodstream at any one time. That’s less than one teaspoon!

When blood glucose levels are too high the effect can be dangerous – causing damage to your nerves, blood vessels, organ and brain; and so the hormone insulin quickly steps in to metabolise the glucose before it causes too much damage.

But then your body notices this decrease in blood glucose. In evolutionary terms not having enough glucose in your blood means you won’t have the energy to get up and hunt for more food. Your regulatory systems recognise this situation as a potential threat so will inform your adrenals to ramp up cortisol production again. (You may also crave carbohydrates right now).

And so in response your cortisol levels rise to increase blood glucose, and the more frequently this happens, the more problems, you are likely to see. And what happens when you can’t concentrate and things go wrong? You get more stressed and your body will release more cortisol!

Re-balancing cortisol production

When I used to work with clients I would help them to tailor ways that would help their cortisol production return to the natural 24 hour cycle.

Some of my recommendations were dietary, such as:

  • Reducing carbohydrate intake, particularly sugar
  • Increasing intake of clean, beneficial and undamaged forms of fat and also of undamaged cholesterol sources to provide both stable energy and the building blocks for optimal hormonal production
  • Timing meals and macronutrients so as to provide continual energy that benefits cyclical hormone production
  • Using specific supplements to reduce emotional and physical perceptions of “threat”

And some related to lifestyle, such as:

  • Sleeping and exercising in a way that encourages a return to cyclical hormone production
  • Reducing stressors that unnecessarily stimulate cortisol production

As I am no longer practising as a health and nutrition coach I cannot give individual recommendations but I hope that you will use this page as an introduction to finding out more!