It has long been known that adequate quality and quantity of sleep are needed for good health. In an exact way instructions exist for achieving health through a balanced diet or regular exercise; there are also instructions for gaining health through a good night’s sleep. These instructions are known as sleep hygiene.
While instructions for good sleep have been around for centuries, the term sleep hygiene was first coined in 1918 by an American doctor called Ferdinand E Daniel. These days, hygiene generally refers to cleanliness or sterility, but the full definition is ‘the conditions or practices conducive to health and preventing disease’.
Sleep hygiene refers to the routines and practices that encourage good sleep. It involves getting your mind and body into a favourable state for sleep and making your bedroom the best possible environment. Therefore, it is intended as a ‘good practice’ that we should all follow for healthy sleep. It is not, as many think, a treatment for insomnia. Insomnia is the difficulty in falling asleep, staying asleep or waking early. While sleep hygiene lays an essential foundation for insomnia treatment as a component of cognitive behavioural therapy, it is not an effective treatment for insomnia by itself.
It is best divided into three sections – scheduling, preparation for sleep and the sleeping environment.
In my previous article, the role of the circadian rhythm in the control of sleep was explained. As humans, we are very reliant on light for our activities, and so we have evolved to have our peak activity levels during daylight hours and rest during the dark. This cyclical fluctuation is governed by an internal body clock known as the circadian rhythm.
The cycle length is set as just over 24 hours, but it is constantly corrected by external stimuli, known as ‘zeitgebers’, which means ‘time-givers’. The main zeitgeber is light, and this whole process of daily correction, known as entrainment, is so that our internal body clocks stay in time with the movement of the seasons.
When working well, our circadian rhythms kick into wake mode around 7 or 8am, keep us alert and awake throughout the day, and then start to wind down in the evening before clicking into sleep mode shortly after we get into bed.
The trick with the scheduling aspect of sleep hygiene is to carry out activities that reinforce the wake phase of the circadian rhythm so that the sleep phase comes more naturally at night. These activities expose us to zeitgebers.
The most important zeitgeber is light, which is why getting outside in the first hour after waking is such a crucial part of sleep hygiene. If this isn’t possible, sitting near a window will have a similar effect. What is usually needed to get full benefit is a bright light on the blue end of the spectrum.
The other key zeitgeber is exercise. Moderate exercise, especially in the first half of the day, can strengthen the circadian rhythm.
Circadian rhythms like consistency, so it is essential to maintain a regular routine. This means going to bed at the same time and waking up at the same time. You generally have more control over your waking up time, which should not be varied by more than an hour at weekends.
With time, the effect of a strong, reinforced circadian rhythm is that you will become one of those people who wake up at the same time every morning, whether you have an alarm clock or not. Once awake, you will want to get out of bed and feel alert throughout the day with no urge to nap. You’ll start to wind down naturally a couple of hours before bedtime, and when you get into bed, you’ll drop straight off to sleep. Even if you want to sleep in at the weekend, you will find this difficult because your circadian rhythm has developed a solid and consistent beat.
This section involves getting your mind and body into the right state for sleep.
Avoiding stimulants such as caffeine and nicotine before bed is a sensible way to promote sleep. Caffeine promotes alertness by blocking the action of adenosine, the chemical that gives us our drive for sleep. Nicotine, found in tobacco, e-cigarettes and vapes, has a similar wakefulness-promoting effect. Not particularly helpful if you’re trying to sleep. The length of time these can stay active in the body varies from person to person, but avoiding them around six hours before you go to bed is usually a safe bet.
Alcohol is also worth avoiding if you want a good night’s sleep. While many people find they might fall asleep faster after they have had a couple of drinks, it tends to lead to quite fragmented, poor-quality sleep. Even if you sleep for around your regular length, you may wake up feeling unrefreshed.
The role of light is also vital in preparing for sleep. In the same way, that bright light on the blue end of the spectrum is excellent for promoting wakefulness early on in the day – in the evening, it will have the same effect and so be very unhelpful! Dimmer light, towards the warmer, red end of the spectrum, does not have the same wake-promoting effect and is much better in a couple of hours before bed. For the same reason, it is often recommended to avoid screen time, as phone and computer screens often use blue light.
As well as having your body in a relaxed state, it is essential to get your mind into the correct zone for rest. Around two hours before bedtime, it’s worth avoiding any mentally stimulating activities. Such activities can be really varied. It could be reading and replying to work emails – this might not feel ‘stressful’ but will stimulate your brain into activity, when what you need to do is start winding down. Or it could be that you call family members in the late evening. Such calls can often be quite emotion-provoking. You might roar with laughter with your sister, have an unwell family member, or have a strained relationship that makes you feel anxious. Such relationships are different for everybody, but it is worth reflecting on whether having these calls late at night is helpful, or whether there is a way to find time for them earlier on in the day.
Humans are somewhat unperceptive to sight and sound while sleeping. In fact, during evolution, noise may indicate danger, so the brain is designed to wake up if it hears certain sounds. And if you think back to how light is a potent zeitgeber, perceiving light even through your closed eyes can have a strong waking effect. Even if you do not wake up entirely, such stimuli are known to pull you back to a lighter state of sleep so that you will not feel as well-rested in the morning. This is why it is advised to make your bedroom as dark and quiet as possible. Many of today’s electronic devices have alarms and throw-out lights, so it’s worth getting these out of your room if you can.
Very often, curtains do not quite meet in the middle, which means streetlights can shine into the room, or you get a blast of light when the sun comes up, which might be several hours before your alarm is set. Black-out curtains or blinds (or both if necessary!) are very reasonably priced and can have a massive impact on your sleep quality and quantity.
Where possible, it is worth investing in a quality mattress. While this initial price can sometimes seem high, if you consider that a third of your life is spent lying in bed, it’s worth getting something that suits your body type and facilitates effective sleep.
The last key point when thinking about how the sleeping environment can influence your sleep is regarding pets. It can be great cuddling up to your cat when you drop off to sleep, or having your dog lie on the bed so you both feel like part of the pack. Still, pets have very different sleeping habits from humans, and we often mix less well than you think. For one, they can wriggle around and disturb you even when they’re asleep. And for seconds, they usually have a much shorter sleep period than humans, which means while they might be fast asleep when you get into bed, they are very likely to wake up before you and become a disturbance. It’s a much better idea to cuddle with your pets on the sofa before bed, but make sure they sleep in a different room once you turn in.
In rounding off the subject of sleep hygiene, it is worth mentioning a few things. Firstly, sleep hygiene should be seen as advice for good sleep, not as a set of fixed rules. The value, really, is in understanding the idea behind the advice rather than in following it to the absolute letter.
Secondly, everyone is different. Not all parts of sleep hygiene apply to us all in the same way. One person might find they can check their work emails late at night and still fall straight to sleep, whereas another person will find this always sets their mind racing in a way that keeps them up for hours. Some people can drink coffee after dinner without issue, but others have to have their last cup at lunchtime. If you feel that your sleep could be better, then improving your sleep hygiene is a sensible place to start – but it’s worth spending time reflecting on the subject and deciding what’s most relevant for you as an individual.
For information regarding sleep disorders, or if you’d like to book a consultation, please visit https://www.thebettersleepclinic.co.uk.