We've all heard we need to get our eight hours in, but what actually happens if we're not racking up the full amount of sleep each night? There's the psychological impact – most of us will have been told to “sleep on it” before making big decisions – but there are physical implications, too. And, with a recent survey finding that 60% of Brits get six hours of sleep a night at most, we ought to be clued up on how missing out on all that extra zzzz can effect us.
Of course, everyone can have a bad night's sleep every now and again – and actually, most sleep experts will advise that the best way to nod off is not to get too hung up worrying about it. But if you're struggling with insomnia that's affecting your daily life, you may want to reach out to your GP.
How much sleep should you get a night?
It's generally accepted that adults should be clocking in between seven and nine hours of sleep a night. According to the National Heart, Lung & Blood Institute: “adults who sleep less than 7 hours a night may have more health issues than those who sleep 7 or more hours a night.”
So how can a sleepless night affect us?
7 things that can happen to your body when you don't get enough sleep
Turns out sleep exhaustion is not an aphrodisiac and the more well-rested you are, the better your sex drive is likely to be. One study found that one hour of extra sleep for women correlated to an increased sex drive of 14%. Likewise, women with longer average sleep duration reported better genital arousal than women with shorter average sleep length.
Our perception of pain is skewed when we're not properly rested. A study in The Journal of Neuroscience monitored the brain activity of healthy participants after a full eight hours of sleep and again after they'd been kept awake for over 24 hours. In each case, pressure and heat was applied to an uncomfortable level on the participants arms and legs. Scans showed that when the group had been deprived of sleep, their perception of pain was heightened. There was an average 120% spike in activity in their somatosensory cortex (the region in the brain that interprets pain). Meanwhile activity dropped in their striatum and insula (regions that typically dampen the perception of pain), so knocks and pressure felt more painful.
A separate study noted that “two thirds of all chronic pain patients report poor sleep quality and recent data supports that sleep disturbance can cause or worsen acute and chronic pain.” Therefore, there is evidence to suggest that people who suffer from pain may be aided by improving their sleep.
Most of us know this already, but if you (and your brain) are tired, your ability to problem solve and make decisions can be impaired. One study, which tested well-rested and sleep-deprived participants across a range of tasks, found that those who had been subjected to two nights of sleep deprivation had significantly blunted reactions to problems presented to them, and particularly struggled to adapt to uncertainty and changing circumstances. Often the error would register, but with diminished affect or response. Another study found that a moderate amount of poor sleep can be more detrimental to performance than an equitable amount of alcohol.
A transformative supplement.
The term ‘beauty sleep’ is no joke. When we sleep, our body takes on the nightshift of rejuvenating our skin – the actual dream, right? “When it comes to your skin, sleep is a fundamental requirement,” explains top consultant dermatologist, Dr Anjali Mahto. “Experimental studies have demonstrated that lack of sleep can make individuals look less healthy and more tired. Studies aside, it’s not rocket science to see that sleep deprivation can worsen under-eye circles and cause sallow, dull skin,” Dr Anjali adds.
Our skin in naturally programmed to go into repair mode at night. “The skin’s circadian rhythm affects nearly all of its functions. This includes skin hydration and water loss, oil or sebum production, blood flow, skin cell division and barrier function. These processes do not proceed at the same rate during the day and show peaks and troughs of activity," Dr Anjali explains. Missing out on much-needed rest can mean that these processes malfunction.
Specifically, lack of sleep can create a spike in cortisol (the stress hormone). A study from Sleep Medicine found that increased levels of cortisol can trigger excess sebum production. On the flip side, poor sleep can impair the skin barrier's ability to function. Our skin barrier is essential for keeping moisture in, so when it's compromised, it can lead to trans-epidermal water loss (aka dry skin). A study in the Journal of Clinical Medicine found that lack of sleep is linked to increased skin dullness, while it's widely known that sleepless nights correlate to dark under eye circles. Our collagen production (collagen is essential for bouncy, plump skin) is also impacted by our sleep. If we don't get enough, it can inhibit the abundance of growth hormones which stimulate cell reproduction, cell regeneration and collagen. Without them, you're likely to notice more lines and wrinkles.
Sleep is brain food when it comes to cultivating and future-proofing our memory. Some research even suggests that “poor sleep is a risk factor for cognitive decline and Alzheimer's disease.”
As for the short term, our brain is able to consolidate the things we've seen or learnt in recent times and commit it to memory while we sleep. News In Health noted that “during a night of sleep, some memories are strengthened.” According to sleep expert Dr. Robert Stickgold of Harvard Medical School, "sleep seems to be a privileged time when the brain goes back through recent memories and decides both what to keep and what not to keep.” Sleep can help cement patterns, too. Memories of certain procedures, like playing a melody on a piano, can actually improve while you sleep.
Unsurprisingly, if you're tired and exhausted you're more likely to be snappy or emotional. Long-term sleep deprivation can contribute toward developing depression. According to research published on the National Library of Medicine “intact sleep" is “crucial” for our general wellbeing, since NREM (non-rapid eye movement)-sleep, REM (rapid eye movement)-sleep and REM-dreaming play key roles in modulating the emotions we experience during the day.
During REM-sleep the activity of our limbic networks (the part of the brain involved in our behavioural and emotional responses) are enhanced to help us process emotional events. The research found that “morning mood improves when REM-sleep is intact, but worsens after a night of sleep deprivation.” Experts also believe dreaming plays a role in integrating traumatic and distressing experiences into memory (which is an important part of moving on and putting problems behind us).
As for facing emotional triggers after poor sleep, “healthy sleep repairs adaptive processing [and] functional brain activity […] and thus improves the capacity to regulate emotions” as well our well-being. In practice, sleep deprivation can decrease medial prefrontal activation (the brain region associated with behavioural flexibility, impulsivity and emotional regulation), which can restrict how positive we feel and our ability to function socially.
Please, don't tell me to meditate.
When you're tired, you're more likely to be run down. And when you're run down, you're generally more susceptible to getting sick. Multiple studies have confirmed this, with one trial finding that fewer than seven hours of sleep increases the likelihood of developing a cold, when exposed to it, by 2.94 times, compared to people who slept eight hours or more. Likewise, healthy sleep can contribute to the development of antibodies which are important for fighting infections.
The Centre for Disease Control & Prevention acknowledges that sleep has a powerful effect on immune functioning, noting “sleep loss can affect different parts of the immune system, which can lead to the development of a wide variety of disorders.”
For more from GLAMOUR's Senior Beauty Editor, Elle Turner, follow her on Instagram @elleturneruk
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