Tired of Fight-or-Flight: The Relationship Between Sleep-Deprivation & Anxiety

Sleep-Deprivation & Anxiety 

Are you sleep-deprived? Perhaps unsurprisingly, the answer to this question is likely “yes”. A recent study indicated that two-thirds of adults in all developed nations obtain fewer than the recommended eight hours of sleep each night.[1] Also unsurprisingly, as research into the world of sleep goes deeper, so too does our understanding of the relationship between poor sleep and mental and physical dysfunction. It is this relationship that I want to explore today.

Most of us have given or received advice to go “sleep on it”. This phrase points to a common awareness of the benefits of a good night’s rest on everything from mood and cognitive function, to general health and wellbeing. We experience a deterioration in our quality of life when we’re sleep-deprived; we struggle to feel positive about ourselves and to empathise with others, we become easily frustrated, intolerant, unforgiving, uncaring, and self-absorbed. We might also notice a decrease in focus, motivation, and sex drive; while at the same time experiencing a reduction in our ability to control impulses and behaviour. This in turn affects our ability to make good decisions and live in accordance with our personal code of behaviour and ethics.[2] It’s small wonder that people who experience ongoing problems with sleep also have difficulties with their health, in their relationships, and at work.

By now you might be thinking “Wait, if bad sleep causes anxiety, then what causes bad sleep?” The answer to that, at least in part, is anxiety. Interestingly, anxiety and poor sleep are bidirectional, which is another way of saying that anxiety and bad sleep form a vicious circle. The degree and duration of one’s feelings of anxiety have a direct impact on the quality and quantity of one’s sleep, and vice versa. This is by no means exclusive to anxiety, but is true also for depression, post-traumatic stress disorder, schizophrenia, bipolar disorder, and more. Indeed, as Matthew Walker writes in his book Why We Sleep, there is no major psychiatric condition in which sleep is unaffected.[3]

To better understand the link between poor sleep and anxiety, we need to look at the brain. First, let’s look at the amygdala, sometimes referred to as the fight, flight, or freeze region of the brain. When we’re sleep-deprived, the amygdala becomes more active, leading us to be more negative, fearful, and anxious. This is partly due to a reduction in activity in a region of the brain known as the left prefrontal cortex. Quite different from the amygdala’s fight-or-flight role, activity in the left prefrontal cortex is associated with higher mental processes, finding solutions, and a sense of wellbeing. Imagine the amygdala as the accelerator in a vehicle, with the left prefrontal cortex acting as the brakes. Last, but by no means least, the hippocampus, a little seahorse shaped structure that plays a vital role in consolidation of memories, among other things. This part of the brain also sees a decrease in activity when we’re sleep-deprived, making it harder to learn new information.

Interestingly, despite the negative impact sleep-deprivation has on the brain’s ability to learn and form new memories, information related to what we might term “bad memories” isn’t handled in quite the same way. Instead, negative information is retained, even as positive experiences are disregarded, to keep us alert to risk and therefore out of harm’s way. This is because our brains possess the same survival kit that our prehistoric ancestors relied upon when migrating over harsh terrain, battling other wild tribesmen, and avoiding roaming polar bears. Anxiety was helpful for the continued survival of humanity. However, it’s not particularly useful today when faced with bills to pay, or we’ve had a fight with our spouse, or we’re late for an appointment. Sleep-deprivation exacerbates these negative emotions giving them more weight than if we were better rested.

Where our ancient ancestors may have awakened with the rising sun, and rested with its setting, today we struggle to get enough sleep to give our brain the time it needs to process negative emotions, and this has dire consequences for our mental health.

As a hypnotherapist, I specialise in helping people who struggle with sleep. In fact, the word hypnotherapy is partly derived from the Greek word Hypnos, meaning ‘sleep’. The application here is somewhat of a misnomer; I don’t put clients to sleep during sessions. Instead, I employ “trance”, a deeply relaxed state which promotes feelings of calmness, comfort, and confidence. To break the vicious circle of ‘negative thinking –  anxiety – sleep-deprivation’, I work with my clients to help identify areas of their lives that they would like to improve. This causes a reduction in emotional distress, leading to better sleep, increased energy, and improved overall wellbeing.

The next blog in this series on sleep will look at some of the strategies we can use for getting a better night’s rest. Even just small changes to habits and behaviours can have big results when it comes to overcoming anxiety and improving sleep.


[1] Walker, Matthew, Why We Sleep. London: Penguin, (2018), p.3.
[2] Lewis, Penelope E., the Secret World of Sleep: The Surprising Science of the Mind at Rest. 1st ed. Palgrave Macmillan Ltd., 2013. (Macmillan Science).
[3] Walker, Matthew, Why We Sleep. London: Penguin, (2018), p.149.

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