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The Hormone Behind Your Fight-or-Flight: Cortisol and the HPA Axis Explained

Updated: Apr 16


Cortisol is a stress hormone released by your adrenal glands when your body feels threatened. Often known as the "stress hormone" because it's released during stressful situations, cortisol helps your body deal with traumatic or adverse events.

  • When the body senses a threat, the hypothalamus (part of the brain) releases chemicals to the pituitary gland.

  • The pituitary gland passes on this message to the adrenal cortex (located on the kidneys). In response, the adrenal cortex secretes cortisol into the bloodstream. Cortisol triggers a cascade of stress reactions.

  • The heart beats faster. Blood sugar levels rise. It also travels back into the brain where it affects cognition.

Stress and cortisol are closely interlinked. A stressor is any stimuli that causes anxiety or stress. It can be something physical or psychological, like a threat to your safety or an unexpected change to your environment. It could also be pain, financial worries, relationship issues, or work-related problems.

It tells your body to pump blood faster and to release glucose for energy. However, prolonged high levels of cortisol can do you more harm than good. It's not all bad though, because part of the cortisol function is to help you wake up.

Cortisol levels are naturally higher when you wake up and they gradually decrease throughout the day until it's time to fall asleep. It also helps to regulate your blood sugar levels and your blood pressure.

The problem occurs when your body is under chronic stress. Over time, increased levels contribute to weight gain, high blood pressure, diabetes, skin changes, and low mood. So, it is important to find out how to lower cortisol naturally so that your body doesn't think it is constantly in a fight-or-flight situation.

Steps to manage stress

Reduce stress

When your body is exposed to stress, cortisol is released to keep the body on high alert and can even provide much needed energy, an important factor in the "fight or flight" response. Therefore, stressful situations increase cortisol production. Understanding your own triggers is vital if you want lower cortisol levels. Keep a journal to record stressful situations. You don't have to go into detail, but make a note of what happened and consider why it made you feel bad. You can use this information to find practical ways of managing these situations. For example, stepping away from arguments, learning to say no to extra work, and avoiding unnecessary triggers (including social media) are good places to start.

Recognise stressful thinking

Thinking about worrying or traumatic times are a trigger for cortisol release. Research shows that people who write about stressful events often have increased cortisol levels. In fact, negative thinking has been shown to increase cortisol levels and lower oxytocin (a relaxing hormone and neurotransmitter that calms the nervous system). Thinking about the past or negative emotional thoughts can increase stress hormone cortisol levels. Two thought processes in particular are linked with negative health consequences: rumination (deep thought about a particular topic) and worry.

Sleep hygiene tips

A good night's sleep is key to reducing stress. Cortisol and sleep are closely linked with the quality and duration of your slumber. Plus, the timing of sleep is also a contributory factor, meaning night-shift workers who sleep during the day usually have increased levels of cortisol. Sleep deprivation increases cortisol, particularly the evening after the lack of sleep has occurred. Cortisol is produced by the hypothalamic- pituitary-adrenal (HPA) axis, which is also responsible for regulating sleep cycles. If the HPA axis is activated by stress, illness, or poor nutrition, it can have a knock-on effect on your sleep and subsequent stress hormone levels. The best way to ensure you get restful sleep is to incorporate good sleep hygiene. Make your bedroom a peaceful environment by limiting things that disrupt your sleep, like noise and light. Blackout curtains, an eye mask, earplugs, or a noise machine can help. Sleep hygiene tips for lower cortisol levels Go to bed at a regular time each night. Set an alarm to get you up at the same time each morning.


Chronic stress can feel like an overwhelming burden, impacting mental and physical well-being. While traditional stress management techniques have their merit, incorporating regular physical activity offers a natural and holistic approach with multiple benefits.

Biochemical Modulation: Exercise triggers the release of endorphins, our body's endogenous mood-elevating neurotransmitters. This surge effectively reduces stress hormones, including cortisol, leading to a sense of calm and improved well-being.

Neural Repatterning: Stressful experiences can create a hyperactive loop in the brain, replaying negative thoughts and anxieties. Physical activity alters blood flow to stress-sensitive brain regions, promoting neuroplasticity and reducing the intensity of these loops, fostering greater mental resilience.

Mindfulness in Motion: Engaging in physical activity, whether it be a vigorous workout or a mindful walk, naturally draws our focus to bodily sensations and the rhythm of breath. This shift in attention acts as a form of moving meditation, momentarily disengaging us from external stressors and promoting mental clarity.

Holistic Health Optimization: Stress wreaks havoc on both mind and body. Regular physical activity combats this by bolstering overall health. Through improved cardiovascular function, weight management, and enhanced sleep quality, the body becomes better equipped to handle stress effectively.

Time constraints are often cited as a barrier to stress management. However, even brief bouts of physical activity, as little as 15 minutes daily, can have a significant impact. Short walks, stair climbing, or desk stretches can easily be incorporated into busy schedules, offering immediate stress relief and long-term well-being benefits.

In conclusion, incorporating physical activity into your routine is not simply about losing weight or building muscle. It is about empowering yourself with a potent tool for stress management. By harnessing the biochemical, neural, and mindfulness-promoting effects of movement, you can cultivate a calmer, more resilient self.

Have a laugh

Beyond fleeting joy, laughter emerges as a potent stress-busting tool backed by science. It fuels feel-good chemicals, calms the nervous system, strengthens social bonds, and helps us see the funny side of things. A hearty chuckle even loosens tension, sparks creativity, eases pain, and boosts our immune system. Laughter's ability to promote restful sleep and enhance overall well-being makes it a readily available weapon against the modern-day battle with stress. So, let loose, share a laugh, and unlock the power of this simple yet potent stress reducer.

Get a pet

Interactions between humans and dogs increase oxytocin levels in both owners and their furry friends, and decrease cortisol levels in humans, relieving stress. Another study showed that when comparing dog owners with non-dog owners, introducing non-dog owners to a canine companion caused a greater drop in stress hormones. Pets bring other health benefits too. They provide a focus, reduce blood pressure, and can help combat loneliness. And it's not just dogs that can have a positive impact on health and wellbeing, cats do too, as do caged birds like canaries and budgies.

FACT Physical interaction between dogs and their owners actually increases cortisol in dogs. It's not thought to be stress-related, more anticipation to play.

Foods that lower cortisol

Diet is an important factor in health, including lowering cortisol, but eating the wrong foods can trigger cortisol release, like sugar. Regularly consuming high levels of sugar can keep your cortisol levels elevated, which has also been associated with greater risk of heart disease in obese men.

Cortisol interacts with neurotransmitters (chemical messengers in the brain), which are vital for regulating mood. Both hormones and food contribute to the production of these chemical messengers. That's because many foods contain the nutrients needed to build them.

Foods that are naturally high in polyphenols lower the cortisol stress hormone. The long-term health benefits of drinking green tea, for example, are well established, and drinking just a half a cup per day keeps the risk of developing depression and dementia low.

Gut microbiome, cortisol and stress

The gut microbiome, the trillions of microorganisms living in your intestines, plays a surprising role in regulating not just digestion, but also your mental health and stress response. An unhealthy gut microbiome, characterized by an imbalance of "good" and "bad" bacteria, can contribute to chronic stress in several ways:

Inflammation: Unhealthy gut bacteria can increase inflammation throughout the body, including in the brain. This chronic inflammation disrupts various pathways linked to stress response, making you more susceptible to stress and slower to recover from stressful situations.

Neurotransmitter Dysregulation: Gut bacteria influence the production and breakdown of neurotransmitters like serotonin, dopamine, and GABA, all crucial for mood, sleep, and emotional regulation. An unbalanced microbiome can disrupt this delicate balance, leading to anxiety, depression, and increased stress sensitivity.

Leaky Gut: In an unhealthy gut, the intestinal lining becomes more permeable, allowing bacterial toxins and inflammatory molecules to leak into the bloodstream. This "leaky gut" condition can further trigger inflammation and activate the stress response, contributing to chronic stress.

The hypothalamic-pituitary-adrenal (HPA) axis is the body's primary stress response system. Gut bacteria influence this axis through various mechanisms, potentially leading to overactivation or dysfunction, resulting in chronic stress and difficulty controlling cortisol levels

Sleep Disruption: Gut bacteria also play a role in regulating sleep quality. An unhealthy microbiome can lead to sleep disturbances, which in turn impair stress recovery and worsen the effects of chronic stress.

Feeling Stressed? You're Not Alone!

Are you struggling with the crippling effects of chronic stress? Are you experiencing:

  • Fatigue

  • Anxiety

  • Difficulty sleeping

  • Difficulty concentrating

  • Emotional exhaustion

Join us for a 2 hour workshop where we will teach you how to manage stress and improve your overall well-being. Led by Functional Medicine Practitioner Jenny Hague, you'll learn about:​

  1. Your personal Stress Index

  2. Different types of stress and their impact on your body

  3. The HPA axis and its role in stress response

  4. Personalized stress relief approaches

Let us know if you are interested in this workshop and we will let you know the dates and times.

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