Constantly stressed? Dr Amir Khan reveals whether you should get your cortisol levels checked

Cortisol is the hormone we seem to hear about more than any other. While typically it’s been associated with stress or our body’s ‘fight or flight’ response, it also affects other parts of our body. Social media might blame high cortisol levels for all kinds of health problems, such as poor sleep, anxiety and brain fog, but NHS GP Dr Amir Khan says it’s actually a very “misunderstood” hormone.

The adrenal glands produce cortisol, but its levels change throughout the day depending on what the body needs it for. Dr Khan, woman&home’s resident doctor, says “without cortisol, we simply couldn’t survive”.

“We need it to wake us up in the morning, regulate our blood pressure and blood sugar, control inflammation, fight infection and help us respond to physical and emotional challenges," he says.

Cortisol levels naturally rise when we wake up. They make us feel alert, release energy for the day and get us ready for life. They then fall throughout the day and reach their lowest level overnight.

Home tests and private testing appointments claim to accurately measure cortisol levels, but Dr Khan warns against these. Measuring hormone levels is tricky because of these highs and lows.

“They may tell you what your cortisol level was at one particular moment, but not whether it’s normal for that time of day or whether it’s causing your symptoms,” says Dr Khan. “Without the right clinical context, there’s a real risk of over-interpreting perfectly normal results or creating unnecessary worry.”

Exercise, illness, pain, poor sleep, shift work, medications, pregnancy, caffeine, alcohol, anxiety, and even the stress of having a blood test can skew the results. "A single cortisol reading tells us very little on its own," he explains.

If you’re feeling tired or stressed and want to lower your cortisol levels, your GP will review several factors instead of testing your cortisol. Our bodies have many hormones that can rise and fall in midlife, causing a range of health symptoms.

Dr Khan says a cortisol level test will be requested “when your symptoms suggest a specific hormone disorder, such as Addison’s disease, where cortisol is too low, or Cushing’s syndrome, where it’s too high”.

One blood test can’t be relied on for a diagnosis. “We often use carefully timed blood tests, saliva samples, 24-hour urine collections or suppression and stimulation tests because interpreting cortisol is far more complicated than reading a single number,” he adds.

“I always say, if you’re experiencing ongoing fatigue, unexplained weight changes, muscle weakness, skin changes or other persistent symptoms, speak to your GP. Treat the person, not just the hormone," he says.

How to manage high cortisol levels

If stress is impacting your daily life, it's important to speak to your doctor. If you're looking to lower your stress levels, the following tips may help:

• Eating a balanced diet: We might choose high-sugar foods to comfort us when we're stressed, but these can actually raise our cortisol levels. Choose protein-rich and whole foods that will fill you up instead.
• Exercising regularly: Moving our bodies improves our mood and helps us relax, which will keep cortisol levels stable. Just make sure you avoid vigorous exercise right before bed because this can increase your cortisol and stop you from getting to sleep.
• Prioritising good sleep: One of the causes of insomnia is high cortisol levels at the end of the day. Sleep better and improve your bedtime routine by swapping your phone for a book and practising other relaxation techniques such as meditation or journaling.
• Cutting down on caffeine: We know that too much caffeine can make us feel jittery or anxious, and this will elevate our cortisol levels. Switch to no- or low-caffeine drinks and avoid it before bed.
• Trying meditation: Mindful activities such as meditation can help bring down high cortisol. Focusing on breathwork and stillness, done at any time of day, can release the happy hormone serotonin and improve anxiety and sleep.
• Taking magnesium: Studies have shown that magnesium can block or reduce the pathway that sends cortisol to our brain.