What is Cortisol? Understanding Cortisol Levels

Most people know cortisol as the ‘stress hormone’. It’s associated with feelings of irritability, anxiety, tiredness and, well, stress. And, in the last couple of years, this hormone’s already tarnished reputation has been damaged further. Videos and images of people on social media with so-called ‘cortisol face’ have been viewed by millions. 

Despite all this negative press, cortisol is in fact a crucial hormone that plays a very important role in your overall health. We spoke with Reema Pillai, a London based nutritionist who’s registered with the British Dietetic Association to learn more about this hormone. 

In this article, you’ll learn:

• What cortisol is

• Rare conditions caused by low or high cortisol levels

• Whether you need to worry about your cortisol levels

• Whether you should get cortisol blood tests

• The influence of your diet on cortisol levels

• Other ways to manage stress and cortisol

What is the hormone cortisol?

Cortisol is a hormone that is produced by your adrenal glands. A hormone is a chemical that transmits messages around the body. 

“Cortisol is known as the stress hormone”, says Reema, but “it is also responsible for maintaining a constant blood pressure and blood sugar levels”. Cortisol also plays a role in several other bodily processes, including heart rate, metabolism, and even anti-inflammation. 

While cortisol doesn’t just affect stress, it’s useful to understand its relationship to this feeling. 

Simplifying somewhat, when you encounter a stressful situation, your brain processes the information, and ‘tells’ your adrenal gland to release cortisol into the bloodstream. That chemical message then informs other parts of your body to be prepared and triggers the ‘flight or fight’ response. Its effects include:

• Increasing heart rate

• Increasing respiratory rate

• Increasing your alertness

• Making blood pressure rise

• Increasing sugar levels in the bloodstream 

Our bodies evolved to release cortisol in stressful situations. Here’s why. 

Imagine you were an ancient human and you crossed paths with a sabre toothed tiger outside your cave. By releasing cortisol hormone levels and increasing your heart rate and blood sugar, your body would be primed to start running away from the threat, giving you a much needed boost. 

So, in many ways cortisol is incredibly helpful to us. Reema points out that: “Cortisol is crucial for our health, and helps support our health for many reasons”. 

Reema lists some of the ways cortisol is useful for you: “[It] is released when you need to maintain healthy blood sugar levels, allowing more glucose to reach the brain and other organs such as the liver and muscles. It is also involved with balancing blood pressure levels. It is a hormone that supports the fight or flight response during stressful times, which is useful in those moments. Cortisol is also important for our immune function, supporting the production of certain antibodies and reducing proinflammatory cells”. 

Learn more: What is stress?

Should you be worried about your cortisol levels?

As mentioned above, cortisol has gathered a fair amount of attention in the last couple of years, with social media influencers discussing the supposed phenomenon of ‘cortisol face’ (some people have claimed the hormone is why you might get a puffy face on some days). 

After watching these videos, you may want to know how to lower cortisol levels or feel concerned you might have high cortisol levels. 

However, Reema says that “the average person should not worry about their cortisol levels”. She explains that “stress will lead to an increased spike in cortisol, but this is a normal response of stress for most people – the increase is temporary and does not usually indicate an underlying health issue”. 

Learn more: What is ‘cortisol face’?

Cortisol-related health conditions

There are a couple of health conditions related to high and low cortisol levels. While these conditions can be severe, it’s important to understand that they’re also very rare. 

High cortisol levels may lead to Cushing’s syndrome

Cushing’s syndrome is a disorder that occurs when a person has too much cortisol in their bloodstream, over a long period of time. It is a very rare condition - about 10 - 15 people have it per million every year (that’s less than a thousand people in the whole of the UK for instance). It affects women more often than men. 

People may develop Cushing’s syndrome for a variety of reasons. For some, it may be a side effect of medication. For others, it may be caused by a problem with their adrenal gland, which means their body struggles to regulate how much cortisol to release. 

Cushing’s syndrome has a number of common high cortisol level symptoms:

• Rapid weight gain

• A rounded face

• High blood sugar

• High, uncontrollable blood pressure

• Fat around the back of the neck

• Bruising around the stomach

• Thing, easily bruised and fragile skin

• Depression of ‘brain fog’

• Excess facial hair in women

Reema says “If you are experiencing any of these symptoms (which usually are quite severe), then I would recommend speaking to your doctor first before assuming cortisol is the issue”. A medical professional can diagnose the condition and provide guidance on how to decrease cortisol levels. 

Low cortisol levels are associated with Addison’s disease

Addison’s disease is another rare disorder (about 9,000 people have it in the UK). The disease damages the adrenal gland, so it can’t produce enough cortisol. 

The main cause of Addison’s disease is believed to be autoimmune disorders, where the immune system attacks the adrenal gland. 

Low in cortisol symptoms caused by Addison’s disease include:

• Extremely low energy and lack of motivation

• Weak muscles

• Low mood 

• Weight loss

• Low appetite

• Increased thirst

• Nausea and vomiting

Addison’s disease can be treated effectively. So, if you have experienced any symptoms, it’s really important to get them diagnosed by a doctor. 

Is it worth getting a cortisol blood test?

If you’re worried that you have either low or high cortisol levels, you might be thinking about getting a blood test. There are various companies that provide blood testing kits that you can use to take your blood. You then send it to a lab for analysis. This can then help inform you about your cortisol levels. 

This kind of personalised healthcare can be helpful for some people. But do you really need it? 

Reema says “although I would not recommend everyone to get a cortisol blood test, it would be recommended if you have certain symptoms that warrant for it to be tested. This includes sudden and unexplained weight loss, extreme fatigue, nausea and vomiting, as this can be a sign of low cortisol”. 

All the same, Reema advises talking to your doctor for a diagnosis first, rather than assuming cortisol levels are the cause of any discomfort you’re experiencing. 

Reema also points out that “cortisol levels will naturally go up and down during the day”. So, a single blood test would not be very informative, since it only provides a one-off snapshot, rather than a longer term picture. 

Can your diet influence cortisol levels?

If you’re thinking about how to decrease cortisol levels, then you might be surprised to learn that your diet can play a part. 

Reema explains: “Research has found that a regular, high refined sugar diet, with high levels of saturated fat can result in high cortisol levels, compared to a diet high in whole grains, fruits, vegetables and unsaturated fats”. 

Studies have found that, when people switch to a more balanced diet, with carbohydrates coming from whole foods, they may have lower cortisol levels. This could help minimise the chances of over-exposure to cortisol. “Generally, following a varied and well balanced diet will support healthy cortisol levels” Reema concludes. 

Another possible link between diet and cortisol levels relates to your gut microbiome. “There is a link between mental health and our gut health, in terms of supporting a healthy gut microbiome,” Reema explains. “Therefore, consuming foods that support a healthy gut can link to reduced stress and anxiety levels, which in turn will support lower levels of cortisol release”. 

 To support cortisol hormone reduction through your diet, Reema also notes that: “foods that may help in particular include fruits and vegetables, going for a variety of colours to obtain the best range of antioxidants. Whole grains are important due to the fibre levels, which supports the growth and diversity of gut bacteria”. 

Finally, Reema notes that “healthy fats found in nuts, seeds and oily fish can support brain health and reduce stress levels”. 

Related: Can I Balance My Hormones With Diet?

Getting to the underlying cause of high cortisol levels

If you’re worried about your cortisol levels, then it might be worth thinking about what’s really triggering your stressful feelings. 

Trying to control the amount of cortisol in your bloodstream is a bit like treating the symptom, rather than the cause (unless, of course, you do actually have Cushing’s syndrome). While it might at first appear to make sense to want to lower cortisol, your body is going to keep producing it if you continue finding yourself in stressful situations. 

There are many reasons you might be feeling chronic stress. It could be related to work, unhappy relationships, money problems or your living environment, among other things. Dealing with the underlying causes of stress is often super complex - there often aren’t easy answers. 

Every situation is unique, but here are some general pointers for managing chronic stress:

• Ask for help: Friends, family or coworkers may not be aware of how much you’re struggling. A problem shared is a problem halved. 

• Get professional support: Your GP should be your first port of call. You might also find it valuable to talk to a qualified therapist, counsellor or life coach. 

• Eating well: Making sure you eat a healthy, balanced diet can help with managing stress and cortisol levels, as Reema explained. 

• Exercising: Aim to get at least 150 minutes of exercise per week and improve your overall fitness. 

• Self help: Podcasts, books and mindfulness apps can all provide new ways of looking at problems.

• Get more sleep: Good quality sleep can help your body deal with stress more effectively. 

• Change the situation: It’s easier said than done, but if you can change or leave the situation that’s causing you long-term stress, this can help eliminate the root cause. 

Cortisol is your friend

Thanks to its association with stress and so-called ‘cortisol face’, this hormone has something of a bad name. Nevertheless, cortisol is actually crucial for your long term health and, besides triggering stress reactions, also helps with many other bodily functions. 

Even when cortisol gives you that feeling of stress, this isn’t a ‘bad’ thing. It’s specifically designed to help you deal with potentially dangerous situations - it might even save your life one day!

Also, if you’re often feeling stressed, then cortisol is your body’s way of telling you that something needs to change. 

Want to learn more about living well? Read our guides.