Why am I tired all the time? The science of sleep

Naps, alarms, sleeping pills, sheep: Dr Nick Knight describes why we need sleep, how much is enough, and how to make the most of it

“I never had this problem on that date last week”, I yawn pitifully to myself as the whites of my eyes pierce the darkness, their only companion the illumination of my mobile-phone screen as yet another message comes through.

Like many, last night, I really struggled to fall asleep. Sleep is a bit like queuing in England - we don’t know why we have it but wow, we really can’t do without it. With modern life packed with increasing and competing pressures from work, family, and social change, many of us, about a third of the UK population in fact, face the prospect of six hours sleep per night or less, according to a study by The Sleep Council.  As a result, we exist in an era in which the modern populace experiences excessive daytime sleepiness and fatigue secondary to this chronic sleep loss.

Read more: The truth about bullying
The effects of too much fat, sugar, and salt

Sleep can be defined as that reversible behavioural state in which you are perceptually disengaged from, and unresponsive to your environment. The reversible part is important, for without that, you are in a coma.

You can divide your sleep into four stages. The first three stages are called non-rapid eye movement (non-REM) in which you fall into a progressively deeper sleep with increasingly less reaction to environmental stimuli (like your fidgety partner). The final stage, called rapid-eye movement (REM) sleep, is where you are essentially an active brain in a paralysed body - and it is here that you dream. Now you cycle through all four stages about every 90 minutes (with 25% of your time being spent in REM sleep) and so overnight you will experience roughly 5 to 7 sleep cycles. I know, I know – it’s never enough.

Of course the question is, why do we sleep? After all, there are no known animals (including us) that live without sleep – so it must be needed. Frustratingly however, the honest and remarkable answer is that we don’t know what the key function of your sleep is. Generally, however, it is (and I am sure you would agree) accepted to function in order to permit recovery from previous wakefulness and prepare you for functioning in the subsequent wake period (though, yes, admittedly, sometimes that doesn’t quite work out as we had hoped).

It is too appreciated that there are very important biological functions to sleep, which include supporting your body’s physiological processes, memory processing and learning.

Of course modern living, whether a result of work or play, occasionally lends itself to a sleepless night or two. In fact, The Sleep Council say that almost half of Britons say that stress or worry keeps them awake at night. The result is that you become sleep deprived. If you then continue this pattern of ‘partial sleep reduction behaviour’ you would slowly accrue a sleep ‘debt’; this is a bit like over-spending on your credit card – you will need to pay back before you can function properly.

Now, I am sure that you would have experienced the fury of 'sleep debt' at some point – you know, that feeling as your body becomes uncontrollably engulfed with that increased drive to sleep, decrease in daytime alertness, and fall in physical and mental performance. Sleep deprivation negatively impacts upon a plethora of your psychomotor performance – accuracy, reaction times, decision-making, errors rate, and mood. After a run of long hospital shifts, sleepless nights, I know I’m about as much use to anyone as a third-wheel on a date.

Modern day healthcare loves to put a number on things: we must exercise 150 minutes each week, our total cholesterol must be less then 5 mmol, and we should drink 2 litres of water a day - I mean, the list is endless. What about sleep, though? This is a very interesting question, since the answer is that scientists are not really sure. The National Sleep Foundation recommends you get between 7 to 9 hours of sleep per night. Now I don’t know about you but I can’t remember the last time I had 9 hours of sleep (even at only 31 years of age, my bladder refuses to let me, sadly). And of course, the frontiers of science continue to march forward; scientists in the US are working towards what they suspect is a more precise (and possibly lower) answer to the question, reflecting our evolving 24 hour habitual patterns of activity.

So as you read this, perhaps through weary eyes and sluggish brain, you may find yourself wondering how you can achieve a better night’s sleep. Sadly, there is no miracle cure but rather a very common sense set of principles, called Sleep Hygiene, that you can follow. These principles may help you to control the behavioural and environmental factors that precede your sleep. If you were to manage to implement these, ok, you might not create an Indonesian yoga retreat with whale music, but you may just make your bedroom and mind a cleaner, more uncomplicated, sleep-inducing environment to promote more restful, effective sleep. This can, in turn, endorse better daytime alertness.

Now, “I can’t sleep, doctor” is a common presentation to general practice, and, is often punctuated with “can I have something to help me sleep?” Although over 10 million prescriptions are issued for sleeping tablets every year in England, sleeping tablets are not panaceas to poor sleep. They do, however, have their place in management for you if you are suffering true bout of insomnia resistant to non-pharmacological treatment. Even then, though, this is ideally given only for a short period of time owing to the risk of dependency, increased tolerance, and next day drowsiness.

Finally, I wanted to touch on something that many of us love – a nap. The nap has been shown to enhance your information processing and learning, and increase your alertness and motor skills. Importantly too, it helps avoid ‘burnout’, that irritating, frustrating, poorer performance you may experience with mental tasks.

It is thought that the networks of neurones within your brain, and in particular your visual cortex (the part associated with vision), become gradually saturated with information through repeated mental engagement during the day. This saturation reaches a threshold where it prevents further brain processing, and so, you then experience ‘burnout’. This can be seen as your brain’s safety mechanism - like a pressure-release value. For that state of ‘burnout’ then allows for the preservation of information that has been ‘processed’ but has not yet been ‘consolidated’ into memory during sleep – the final stage of your learning.

So, if you just want a rest, opt for a 20 minute ‘power-nap’. If you want to lay down some memories and consolidate your learning, then you need a 60 minute ‘consolidation’ nap, for this takes you into your REM sleep where memories are deposited. Oh yes, and if you are wondering why you can sometimes wake up more tired than before the nap, it is because you have broken a sleep cycle too soon. This post-nap lag, known as ‘sleep inertia’, will pass with time.

Right, before my article becomes too long and sleep-inducing, let us summarise. Sleep is a fundamental, functional, and fascinating part of your 24 hour lifecycle. Poorly understood, it functions to help you refresh, recharge, and cement learning and memories. Disruption to it can be potentially devastating and leave you drowsy with poorer physical and cognitive functions. The good news is that you can take charge of it, perhaps by implementing some sleep hygiene principles – the most important of which nowadays, is probably to switch off your phone. As always, if you have any concerns please see your GP. Right, time for a nap…

Dr Nick Knight is a junior doctor based in London with a PhD background in human performance. His blog on life as a doctor can be read at: https://drnickknight.wordpress.com/

Or follow him via Twitter: @Dr_NickKnight

Life and Style
ebookNow available in paperback
ebookA delicious collection of 50 meaty main courses
Latest stories from i100
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    iJobs Job Widget
    iJobs General

    Recruitment Genius: Massage Therapist / Sports Therapist / Physio / Osteopath

    £12000 - £24000 per annum: Recruitment Genius: An opportunity has arisen for o...

    Recruitment Genius: Account Manager / Sales Executive - Contract Hire

    £35000 - £60000 per annum: Recruitment Genius: This industry leader provides c...

    Recruitment Genius: Project Coordinator

    £28000 - £30000 per annum: Recruitment Genius: A Project Coordinator is requir...

    Recruitment Genius: Area Sales Manager - Midlands

    £20000 - £25000 per annum: Recruitment Genius: This is an exciting opportunity...

    Day In a Page

    John Palmer: 'Goldfinger' of British crime was murdered, say police

    Murder of the Brink’s-MAT mastermind

    'Goldfinger' of British crime's life ended in a blaze of bullets, say police
    Forget little green men - aliens will look like humans, says Cambridge University evolution expert

    Forget little green men

    Leading evolutionary biologist says aliens will look like humans
    The Real Stories of Migrant Britain: An Algerian scientist adjusts to life working in a kebab shop

    The Real Stories of Migrant Britain

    An Algerian scientist struggles to adjust to her new life working in a Scottish kebab shop
    Bodyworlds museum: Dr Gunther von Hagens has battled legal threats, Parkinson's disease, and the threat of bankruptcy

    Dying dream of Doctor Death

    Dr Gunther von Hagens has battled legal threats, Parkinson's disease, and the threat of bankruptcy
    UK heatwave: Temperature reaches 39.8 degrees on Central Line - the sweatiest place in London

    39.8 degrees recorded on Tube

    There's hot (London) and too damn hot (the Underground). Simon Usborne braved the Central line to discover what its passengers suffer
    Kitchens go hi-tech: From robot chefs to recipe-shopping apps, computerised cooking is coming

    Computerised cooking is coming

    From apps that automatically make shopping lists from your recipe books to smart ovens and robot chefs, Kevin Maney rounds up innovations to make your mouth water
    Jessie Cave interview: The Harry Potter star has published a feminist collection of cartoons

    Jessie Cave's feminist cartoons

    The Harry Potter star tells Alice Jones how a one-night stand changed her life
    Football Beyond Borders: Even the most distruptive pupils score at homework club

    Education: Football Beyond Borders

    Add football to an after-school homework club, and even the naughtiest boys can score
    10 best barbecue books

    Fire up the barbie: 10 best barbecue books

    We've got Bibles to get you grilling and smoking like a true south American pro
    Wimbledon 2015: Nick Bollettieri - Junk balls and chop and slice are only way 5ft 1in Kurumi Nara can live with Petra Kvitova’s power

    Nick Bollettieri's Wimbledon Files

    Junk balls and chop and slice are only way 5ft 1in Kurumi Nara can live with Petra Kvitova’s power
    Ron Dennis exclusive: ‘This is one of the best McLaren teams ever – we are going to do it’

    ‘This is one of the best McLaren teams ever – we are going to do it’

    Ron Dennis shrugs off a poor start to the season in an exclusive interview, and says the glory days will come back
    Seifeddine Rezgui: What motivated a shy student to kill 38 holidaymakers in Tunisia?

    Making of a killer

    What motivated a shy student to kill 38 holidaymakers in Tunisia?
    UK Heatwave: Temperatures on the tube are going to exceed the legal limit for transporting cattle

    Just when you thought your commute couldn't get any worse...

    Heatwave will see temperatures on the Tube exceed legal limit for transporting cattle
    Exclusive - The Real Stories of Migrant Britain: Swapping Bucharest for London

    The Real Stories of Migrant Britain

    Meet the man who swapped Romania for the UK in a bid to provide for his family, only to discover that the home he left behind wasn't quite what it seemed
    Cheaper energy on the way, but it's not all sunshine and rainbows

    Cheaper energy on the way, but it's not all sunshine and rainbows

    Solar power will help bring down electricity prices over the next five years, according to a new report. But it’s cheap imports of ‘dirty power’ that will lower them the most