Cortisol: your stress hormone

Cortisol: what you need to know about your main stress hormone

Let’s talk about cortisol – your body’s built-in alarm system. It’s your main stress hormone, made by your adrenal glands, and it plays a big role in keeping you functioning day to day. It helps you manage energy, mood, sleep, inflammation, blood sugar, blood pressure – and yes, even fear. In short, cortisol is involved in a lot.

Your brain monitors your cortisol levels and adjusts them as needed. This internal system works beautifully when we’re in balance. But if stress becomes constant or overwhelming, cortisol can start working against you, not for you. That’s when health issues can creep in – and it’s definitely time to take a closer look.

Cortisol: your body's stress responder

Cortisol is often nicknamed the "stress hormone," and for good reason. It’s released by the adrenal glands in response to stress – whether that’s sudden (like an emergency), ongoing (think: work deadlines or family demands), or extreme (like trauma or illness). Its job is to help you cope by shifting your body into “survival mode” – regulating energy, blood sugar, and even immune responses.

Short bursts of cortisol? Totally normal. Long-term high cortisol? That’s a different story.

Why your body needs cortisol (but not too much)

During stressful moments, cortisol gives you a quick energy boost and helps you focus. Your body puts non-essential functions like digestion or reproduction on the back burner to prioritise immediate survival.

The problem? Most of us aren’t dealing with short-term stress anymore. It’s often chronic – juggling work, parenting, sleep disruption, and everything else. And prolonged high cortisol can lead to things like fatigue, weight gain (especially around the middle), blood sugar issues, and even suppressed immunity.

How cortisol is regulated: The HPA axis in action

Your cortisol levels are carefully managed by something called the HPA axis – short for hypothalamic-pituitary-adrenal axis. This is a communication loop between your brain and adrenal glands. Here’s how it works:

• The hypothalamus senses low cortisol and releases CRH (corticotropin-releasing hormone)

• The pituitary gland responds by producing ACTH (adrenocorticotropic hormone)

• The adrenal glands get the message and release cortisol

This feedback loop helps keep your cortisol levels balanced – unless something disrupts the system (like chronic stress, illness, or poor sleep).

What happens when cortisol is too high?

Prolonged high cortisol, also called hypercortisolism, can happen for a few reasons – often due to long-term steroid medication or, less commonly, from hormone-producing tumours.

One condition linked to excess cortisol is Cushing’s syndrome. Symptoms can include:

• Rapid weight gain (especially around the face and belly)

• Thinning skin and easy bruising

• Muscle weakness

• High blood pressure and blood sugar

• Irregular periods or excess hair in women

  
  

Left untreated, it can lead to serious health problems, so if you’re concerned, it’s important to seek support.

And what if cortisol is too low?

On the flip side, low cortisol (also known as adrenal insufficiency) can be just as dangerous. This can be caused by:

• Primary adrenal insufficiency (Addison’s disease) – often autoimmune, where the adrenal glands are damaged

• Secondary adrenal insufficiency – when the brain fails to signal the adrenal glands properly

  
  

Symptoms may include fatigue, low blood pressure, salt cravings, and darkening of the skin. In either case, medical attention is essential, as untreated adrenal insufficiency can lead to a life-threatening adrenal crisis.

How to test your cortisol levels

If you’re feeling “off” and suspect cortisol might be part of the picture, your GP or practitioner can run tests. Cortisol is usually highest in the morning (around 10–20 mcg/dL) and lowest in the evening. These tests can help identify patterns and guide next steps in supporting your stress response.

Supporting healthy cortisol levels naturally

Medical support is important when cortisol is too high or low – but lifestyle changes can also play a powerful role. Here’s where you can start:

💤 Prioritise quality sleep

Aim for 7–9 hours a night. Cortisol is closely tied to your circadian rhythm, so consistent bed and wake times really help.

🚶‍♀️ Movement

Regular movement helps regulate cortisol and release those feel-good endorphins. Brisk walking, strength training, or cycling – choose what you enjoy and stick with it.

🧘‍♀️ Manage stress intentionally

Deep breathing, meditation, gentle yoga, journaling – these are all powerful tools to calm the nervous system and reduce cortisol over time.

🥗 Nourish with whole foods

A whole-food, mostly plant-based diet supports your gut (which impacts your hormones). Include plenty of fibre, healthy fats, and colourful veggies. Cut back on processed foods and sugar – they can spike cortisol.

💊 Consider supplements (with guidance)

Certain nutrients – like magnesium, B vitamins, vitamin C, and omega-3s – support your adrenal function and help your body adapt to stress. Always speak to a practitioner before starting supplements.

Cortisol and your mental health

Cortisol doesn’t just impact the body – it affects the mind too. Chronic high cortisol is linked to anxiety, depression, brain fog, and memory issues. But low cortisol can cause mental fatigue and emotional blunting.

Finding that sweet spot – not too high, not too low – is key for mental clarity, emotional resilience, and long-term wellbeing.

Final thoughts

Cortisol gets a bad rap, but it’s not the enemy – it’s essential for survival. The real issue is when stress becomes chronic and your stress response system gets thrown off balance. The good news? With the right lifestyle tweaks and support, you can restore that balance – and feel like yourself again.

If you’re navigating midlife stress, fatigue, or hormonal shifts and want personalised support, I’d love to help. Let’s get your body and hormones back on your side.