With the clocks going back at the end of October, it can sometimes play havoc with our circadian rhythm (body clock). That dreaded feeling of trying to wrench yourself from under the duvet and up into action. This feeling could be diminished by trying to ensure we get enough sleep. With the average Briton getting just 6 hours and 35 minutes sleep per night and a worrying 33% of us getting less than 6 hours (1).
Although there are a few different thoughts on how much sleep we need, the general consensus is somewhere between 7-9 hours sleep (2). Your ideal number of hours will depend on your individual needs and lifestyle but the image from the National Sleep Foundation gives a rough guide for each age group. Sleeping too much can be just as bad as sleeping too little, although that is a problem that few of us have.
Just a few of the negative effects of not enough sleep:
1) Increased Risk of Diabetes, Heart Disease and Arthritis
Sleep deprivation increases inflammation throughout the body and decreases insulin sensitivity (this leads to increased appetite which contributes to Number 3). (3,4,5)
2) Decreased Immunity
Not getting enough sleep interferes with how our immune system functions and will make it easier to pick up those seasonal colds and bugs. (2,5)
3) Increased Obesity
We see sleeping as a lazy activity, but a lack of sleep is linked with a higher body mass index and 30% increased risk of obesity (4). Studies suggest that people who sleep fewer than 6 hours per night gain almost twice as much weight over a 6-year period as people who sleep 7 to 8 hours per night.
4) Decreased Mood, Memory, Performance and Alertness
During deep sleep our brains move our short term memories into more long term storage. This frees up more space for the next day for those short term memories. Think of it like a computer saving temporary files to a hard drive to free up the limited short term space. So if you are a student revising for your exams, those extra hours cramming all through the night will probably not do you much good. Another phase of sleep is rapid eye movement (REM sleep) where we are completely relaxed as our excitatory hormone noradrenalin is switched off. This helps us deal with stress, emotions and anxiety. If these important phases are interrupted or not obtained throughout the night then we are more likely to be irritable, slower reactions and generally less able to function at our optimal best. (2,6,7)
First we need to understand a bit more about the two systems that control our sleep: circadian biological clock and sleep/wake homeostasis.
This control is the simplest and is driven by time. The longer we are awake the more the need to sleep increases. However if this was our only control we would be bright and alert first thing and on a gradual decline throughout the whole day. So the body needs a second regulator to help control our urge to sleep.
Our circadian rhythm tends to fluctuate a bit more throughout the day. Adult’s strongest sleep drive usually occurs between 02:00-04:00 at night and then a small rise in the afternoon between 13:00-15:00. Maybe the Spanish have had it right all along with their “Siestas”. Conversely teenagers strongest sleep drive occurs slightly later between 03:00-07:00 and 14:00-17:00. So all those ‘apathetic’ teenager struggling to get up in the morning for school are not just trying to irritate their parents, they have a genuine excuse. Adolescence and puberty changes the balance of our hormones making it more difficult for them to fall asleep before 23:00 and thus harder to get up in the morning as well.
These dips and rises are controlled by a part of the brain called the suprachiasmatic nucleus (SCN) in the hypothalamus. This special part of the brain controls hormones, body temperature and other functions related to regulating sleep. When you are exposed to light first thing in the morning the SCN increases your body temperature and stimulates the release of cortisol, also known as our ‘stress hormone’. This makes us feel alert, awake and ready for the day ahead. This is in a fine balance with another hormone that makes us feel sleepy called melatonin, our ‘darkness hormone’. Exposure to light causes the SCN to stop the pineal gland in the brain from secreting melatonin.
We can start to see how there is a very fine interplay between several parts of the brain, hormones, light, body temperature, etc. Although even today we do not fully understand how sleep is regulated, understanding what drives these cycles and ultimately drives sleep can help us get a better night’s sleep.
1) The bedroom should ideally only be used for sleeping and sex. This way when you enter the bedroom your body is already associating it with bedtime. If you like to work for hours in bed on a laptop then your body will not associate the bedroom with a relaxing environment.
2) No bright lights in the bedroom. Next time you have to replace a bulb in your bedroom pick a lower lumen bulb than you normally would. Remember bright light, in particular white and blue, stop our darkness hormone melatonin from being released. If you really want to go to town on it then having red light bulbs is more relaxing for us at night time. Bulbs that can change colour are becoming more widely available and will be something that everyone has in the future. Getting thicker curtains can also help block out external light from street lamps if this is a problem.
3) Avoid using phones/laptops/tablets in the bedroom. Not only do they emit the ‘blue light’ which keeps us awake but they will also keep our minds active and cortisol levels high. The recommendation is avoid using them up to 2 hours before bedtime. Reading a book or a kindle is far less stimulating as neither emit light. If you can’t tear yourself away from them then at least dim the back lighting as much as possible. Some tablets even have a night mode where the type is white on a black screen. You can also download software which automatically adjusts it depending on the time of day https://justgetflux.com/.
4) Avoid too much stimulation before bedtime. This follows on from the previous point, but watching a scary movie, exercising, smoking, drinking alcohol or caffeine close to bedtime will hamper your efforts of getting a good nights sleep. Some people feel they have to have a TV in the bedroom. If you feel you can’t part with it just watch something lighthearted and not too engaging. Make sure that the final hour before bedtime you are gradually winding down.
5) Get enough exercise throughout the day. We said no vigorous exercise before bedtime, but it is just as important to make sure you are exercising at some point otherwise we don’t burn off our energy stores and won’t feel as tired come bedtime.
6) Try to stick to the same bedtime and wake up time, even at weekends. Our bodies love routine and this is what helps us get into a nice circadian rhythm. If we are constantly changing our sleeping times the body can’t regulate it as easily. This is one reason why shift and night time workers on average are less healthy. Having that odd lie in at the weekend is going to hurt, but just try to maintain a regular time throughout the whole week if possible. If you are a shift worker, get into the best routine possible and try not to disrupt it.
7) Make sure the bedroom is not too hot. Our body temperature slightly drops just before and during sleep. If the bedtime environment is too hot it can delay the release of those sleepy hormones and prevent getting off to sleep. 60-67 degrees is reportedly the ideal temperature for the bedroom.
8) Decrease noise as much as possible. This may sound obvious, but noise can have a very disrupting affect on our sleep. Whether it’s from outside traffic or other noise pollution or inside from your family or partner you have a few choices. Wearing ear plugs can be a simple and effective solution. Failing this, using ‘white noise’ which is a constant ambient sound from a white noise machine, air purifier, fan or anything that creates a consistent and soothing hum can help block out sleep disturbing noises. This is another reason not to have a television in your room as the noise is inconsistent and if left on can disturb your sleep without you realising.
We pay a lot of attention to our diet and exercise as we are constantly told that we need to get these right to stay healthy. This is true, but sleep also plays a key role in keeping us healthy. It is about time we dedicated a little more of our time to ensure we get a good night’s sleep.
We hope you have found this guide useful and interesting. The next installment will cover the more physical side of sleep – sleeping positions, choosing pillows and mattresses.
1) Great British Bedtime Report 2013. The Sleep Council. http://www.sleepcouncil.org.uk/2013/03/first-ever-great-british-bedtime-report-launched/
2) National Sleep Foundation – http://sleepfoundation.org/how-sleep-works/how-much-sleep-do-we-really-need
3) Sleep Loss and Inflammation. 2010 – http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3548567/
4) Circadian misalignment augments markers of insulin resistance and inflammation, independently of sleep loss. 2014 – http://www.ncbi.nlm.nih.gov/pubmed/24458353
5) Loss Of Sleep, Even For A Single Night, Increases Inflammation In The Body. 2008 – http://www.sciencedaily.com/releases/2008/09/080902075211.htm
6) We are chronically sleep deprived. 1995 – http://www.ncbi.nlm.nih.gov/pubmed/8746400
7) How much can an extra hour’s sleep change you? 2013 – http://www.bbc.co.uk/news/magazine-24444634