Feeling tired? Bloated? Having trouble sleeping? Your cortisol levels might be too high – or that’s what social media would have you believe.
Cortisol is the latest chemical to fall under the spotlight as, in many health and wellness influencers’ eyes, it’s to blame for all manner of problems – problems that the correct combination of supplements can, of course, fix.
But what exactly is cortisol? And why is it causing so much trouble?
Cortisol is commonly known as a stress hormone. When we sense a potential threat, the amygdala in our brain triggers the ‘fight or flight’ response: adrenaline and noradrenaline are released to prepare us to do battle or run away. This is what we feel when we jump during a scary movie or are nervous before a big work presentation.
Most of the time the stress doesn’t last long – the scare is momentary, the presentation is only a few minutes – and our adrenaline levels return to normal shortly after it passes. Neuroscientists and psychologists call this acute stress and, in moderate amounts, it’s actually good for us.
Cortisol comes into the equation when that stress is prolonged or feels unmanageable. In these cases, cortisol is released from the adrenal glands on top of the kidneys.
It peaks after 15–20 minutes and, during that time, helps our body to continue responding to the threat by making sure energy is available and blood is flowing to the muscles, as well as keeping our brain alert.
But this doesn’t happen every time we’re afraid or stressed – far from it. “Getting a cortisol response from acute stress is actually quite difficult,” says Prof Stafford Lightman of the University of Bristol Medical School.
“It’s very easy to get an adrenaline response, but causing cortisol release is a challenge. It’s whether you personally perceive something as being a severe enough threat.”
But the stress response isn’t cortisol’s only role. It has other important functions as well, some of which are positive. For example, cortisol helps you get up in the morning: your cortisol levels rise before you wake. Without this increase preparing you for the day, it would be even harder to get out of bed.
Cortisol plays a huge range of roles, Lightman points out. “Cortisol is a signalling molecule – almost every tissue in your body has cortisol receptors: your muscles, your liver, your brain.”
When your organs and muscles receive signals from cortisol, it triggers them to carry out important functions that keep your body stable. For example, when organs such as your liver and pancreas detect cortisol, it helps them to maintain steady blood sugar levels and keep your blood pressure consistent. Cortisol can also trigger anti-inflammatory mechanisms in the body, helping to boost your immune system for short bursts.
“[Cortisol] does multiple things,” Lightman says. “And it’s kept very carefully under control by the body because so much depends on it. In fact, it’s the only hormone you need for life – without cortisol you would die.”
Patterns matter
You certainly need some cortisol, then, but what if you’re worried you have too much of it – an amount that, as the influencers are so keen to point out, could be causing you problems.
Determining that can be tricky, though, as your cortisol levels naturally fluctuate throughout the day (rising in the morning and falling in the evening). The trouble is that the at-home test kits used to measure your cortisol levels ask you to check them just once a day and claim this gives you an indication of whether they’re generally ‘high’ or ‘low’.
Lightman describes these tests as “complete rubbish” and points out that “the variation of normality at any one time point is massive and you couldn’t possibly tell whether someone’s cortisol was high or low. 20 minutes later it might be completely different.”
To really know what’s going on, you would have to measure your cortisol levels many times, over many days – this is how doctors diagnose diseases linked to changes in cortisol release.
To complicate matters further, cortisol is also released in bursts about every hour or so. This pattern changes gene activity and is vital for a whole range of functions. One study recruited healthy volunteers to investigate this, blocking their natural cortisol and substituting it with matching doses that mimicked either a daily (circadian) rhythm without pulses, or a circadian rhythm with pulses (similar to a natural release pattern).
The participants on the non-pulsed protocol scored worse on working memory tasks and reported poor sleep. Those on the pulsed protocol, however, were less able to accurately identify facial expressions, which is conversely linked to better mental well-being. The results suggest that it’s not necessarily the amount of cortisol in your system that affects your ability to function, but the pattern with which it’s released.
Studies on mice also suggest that we’re able to learn new skills better while our cortisol levels are higher, as neuron connections form more easily. But we need cortisol levels to dip for these skills to be stored long-term in the brain.
But even if you could track cortisol over a whole day, this still wouldn’t say much about your health. “You would first have to define normality for that particular person,” says Lightman, “and then show that their pattern for the day fell outside the normal range. Nobody has done that. All these wellness people tell you is that your pattern is ‘dysregulated’, but that’s complete rubbish.”
Don’t panic
Scientists agree that chronic stress is bad for our health and that managing it can make our lives a little better. But, Lightman says, we shouldn’t always jump to blame cortisol.
“Health problems can develop if you experience long-term stress – a divorce, losing your job, something that wakes you up in the night worrying. That doesn’t mean the cortisol is causing it.”
Tackling the source of our stress is the best remedy, rather than resorting to supplements in a bid to reduce our cortisol levels, but this isn’t always an option.
Luckily, we can manage our stress levels in other ways. A 2019 study, for example, found that older people given dance training for three months showed a reduction in their peak cortisol and dancing has also been shown to reduce feelings of stress.
Hugs can also be a great way to deal with short-term stress. One study found that when students received more than their usual number of hugs in a day, their morning cortisol spike was lower the day after.
A walk in the woods can also be beneficial, reducing cortisol levels by 53 per cent in one study.
Far from being the bad guy, cortisol is vital for our bodies and brains, and for the vast majority of us, it’s simply not something worth worrying about.
We’re far better off focusing on the basics of healthy living (diet, exercise and sleep) and stepping away from the influencers trying to sell us the latest fad. Especially when there are moments of joy to be found in the real world instead.
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