3 mins read

Cortisol (9am)

Cortisol, also known as ‘the stress hormone’, is crucial for regulating metabolism, controlling your sleep/wake cycle and much more.

Written by Leanne Edermaniger

April 24, 2024

Reviewed by:

Dr Thom Phillips
In this article:

What is Cortisol?

Cortisol is a hormone produced by the adrenal glands, playing a key role in regulating metabolism, immune response, and the body’s stress response. Often referred to as the “stress hormone,” it helps the body respond to stressful situations by releasing energy and maintaining balance.

  • Produced by the adrenal glands, located above the kidneys.
  • Helps regulate blood sugar levels, metabolism, and inflammation.
  • Plays a critical role in the “fight or flight” stress response.
  • Maintains blood pressure and cardiovascular function.

What Are ‘Normal’ Cortisol Levels?

A healthy cortisol range for both males and females is 160-507nmol/L.

Based on data collected from Forth customers, we found that:

  • The overall average cortisol level is 370.1 nmol/L
  • The average level for men in the UK based on 2877 results is 380.1 nmol/L
  • The average level for women in the UK based on 2659 results is 360.9 nmol/L

Cortisol levels fluctuate throughout the day and in response to various stimuli, including intense exercise.

Because cortisol is involved in the sleep/wake cycle, in most people, cortisol levels are at their highest in the morning when they wake up. They then fall throughout the day, and are usually at their lowest at night, enabling better sleep.

However, in people who work night shifts, this pattern is reversed, suggesting a link with your daily routine. But cortisol is also released in response to intense exercise, which can be critical for energy metabolism during exercise and for recovery.

Therefore, it is important to test your cortisol levels at the right time of day to gain accurate results.

What Causes High Cortisol Levels?

High cortisol levels, also known as hypercortisolism, can result from chronic stress, medical conditions, or lifestyle factors. Prolonged elevated cortisol levels can lead to various health problems.
Chronic stress from work, relationships, or life challenges.

  • Medical conditions such as Cushing’s syndrome.
  • Certain medications, especially corticosteroids.
  • Poor sleep habits or sleep disorders.
  • Excessive caffeine or alcohol consumption.

Symptoms of High Cortisol

High cortisol levels can have widespread effects on the body, often resulting in noticeable physical and emotional symptoms.
Unexplained weight gain, especially around the abdomen.

  • Fatigue and difficulty sleeping.
  • Increased susceptibility to infections.
  • Mood swings, anxiety, or depression.
  • High blood pressure and elevated blood sugar levels.

How to Lower Your Cortisol Levels

If you are experiencing high cortisol levels, how you reduce them will depend on what’s causing them to rise.

If high levels are caused by an underlying medical issue, like a pituitary gland or adrenal gland problem, or because you are taking medication like the oral contraceptive pill, you will need to consult your doctor for advice and to devise a plan.

If you experience high cortisol because of chronic or prolonged exposure to stress, there are several lifestyle changes you can make to naturally reduce your levels. They include:

  • Prioritise good, restful sleep
  • Practice mindfulness
  • Exercise regularly
  • Do something you enjoy every day
  • Laugh
  • Stay connected with friends and family
  • Look after a pet
  • Follow a healthy diet
  • Manage stress and recognise stressful thinking

What Causes Low Cortisol Levels?

Low cortisol levels, or hypocortisolism, occur when the adrenal glands fail to produce adequate amounts of the hormone. This can result from underlying medical conditions or disruptions in hormone regulation.

  • Addison’s disease, an autoimmune condition affecting the adrenal glands.
  • Adrenal insufficiency due to prolonged steroid use.
  • Pituitary gland disorders that impact cortisol regulation.
  • Genetic conditions affecting adrenal function.

Symptoms of Low Cortisol Levels

Low cortisol can lead to serious health issues, often causing symptoms that affect energy, mood, and overall well-being.

  • Extreme fatigue and weakness.
  • Unintended weight loss and reduced appetite.
  • Low blood pressure and dizziness.
  • Nausea, vomiting, or abdominal pain.
  • Darkening of the skin in certain areas (in severe cases).

How To Test Your Cortisol Levels at Home

If you’re concerned that you may be experiencing symptoms associated with high or low cortisol levels, then you can quickly and easily test yourself at home with our Cortisol Blood Test.

Because your cortisol levels naturally fluctuate throughout the day, it’s best to take the test before 10 am, or within 3 hours of waking if you’re an early riser or work nights.

We also check your cortisol levels as part of our:

Written by Leanne Edermaniger

Based in the UK, Leanne specialises in writing about health, medicine, nutrition, and fitness.

She has over 5 years of experience in writing about health and lifestyle and has a BSc (hons) Biomedical Science and an MSc Science, Communication and Society.

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Article references

  1. Hackney, A. C., & Walz, E. A. (2013). Hormonal adaptation and the stress of exercise training: the role of glucocorticoids. Trends in sport sciences, 20(4), 165–171.

  2. Dierckx, B. et al. (2012) ‘Persistence of anxiety disorders and concomitant changes in cortisol’, Journal of Anxiety Disorders, 26(6), pp. 635–641. doi:10.1016/j.janxdis.2012.04.001.

  3. Hirotsu, C., Tufik, S., & Andersen, M. L. (2015). Interactions between sleep, stress, and metabolism: From physiological to pathological conditions. Sleep science (Sao Paulo, Brazil), 8(3), 143–152. https://doi.org/10.1016/j.slsci.2015.09.002

  4. Manary, M. J., Muglia, L. J., Vogt, S. K., & Yarasheski, K. E. (2006). Cortisol and its action on the glucocorticoid receptor in malnutrition and acute infection. Metabolism: clinical and experimental, 55(4), 550–554. https://doi.org/10.1016/j.metabol.2005.11.009

  5. Schmalbach, I. et al. (2020) ‘Cortisol reactivity in patients with anorexia nervosa after stress induction’, Translational Psychiatry, 10(1). doi:10.1038/s41398-020-00955-7.

  6. Broersen, L.H. et al. (2015) ‘Adrenal insufficiency in corticosteroids use: Systematic review and meta-analysis’, The Journal of Clinical Endocrinology & Metabolism, 100(6), pp. 2171–2180. doi:10.1210/jc.2015-1218.

This information has been medically reviewed by Dr Thom Phillips

Thom works in NHS general practice and has a decade of experience working in both male and female elite sport. He has a background in exercise physiology and has published research into fatigue biomarkers.

Dr Thom Phillips

Dr Thom Phillips

Head of Clinical Services