Hindus believe that the universe was created during the cosmic sleep of the god Vishnu. The Native American Ojibwe tribe use dream-catchers at night, believing that they will protect them from harm. Thousands of articles exist detailing the various Islamic interpretations of dreams. Sleep – and what we experience when we do it – is by far one of the most important features of human (and even animal) existence, and said to account for one-quarter to one-third of the human lifespan.
Despite this, so little is done in our everyday lives to accommodate it. Often we view it as a disruption to our valuable time. And even with this dismissive attitude, we struggle to get enough rest – often relying on swigs of caffeine to keep us awake throughout our day.
Recently, there has been more of an interest in understanding sleep. Several books have been published regarding the topic – particularly, Nick Littlehale’s Sleep, which has been used to inform this article. In light of this, the following article will provide an overall understanding of it. We’ll go over sleep’s scientific basis and include tips you can implement to ensure you are getting the rest you need.
What is sleep?
There is no concrete definition of sleep. However, it is universally recognizable. Generally, it is defined as a mental and physical state that recurs for several hours each night. This entails the deactivation of the nervous system, shutting of the eyes, and relaxation of the muscles. It is intended to be a period of mental and physical rest, from which you awake refreshed and ready to face the next day’s events.
Sleep: a human history
There are several theories as to the reasons for and history of sleep. The first is Inactivity Theory. This suggests that rest became a survival adaptation over time. It enabled animals, particularly humans, to become still during their most vulnerable hours.
By contrast, Energy Conservation Theory posits – as its name suggests – that the rest was an evolutionary development. Its purpose was to minimize our need for energy, particularly if food was scarce.
Brain Plasticity Theory suggests that sleep plays an important role in the mental and emotional development of babies and children. Meanwhile, Restorative Theory ties this together with the body’s overall need for reparation and rejuvenation.
There’s no way of knowing exactly how our human ancestors slept, particularly in the various parts of the world. However, a recent UCLA study examining three traditional hunter-gatherer groups in Tanzania, Namibia, and Bolivia provides the closest possible evidence. This study found that the hunter-gatherer groups went to sleep around three and a half hours after sunset – disputing the belief that sleep would originally fall at the point of dusk. They also discovered that the hunter-gatherers tended to rest around six hours in one cycle.
Biphasic and polyphasic types
Much research has been done in order to learn not only about the benefits of sleep but, equally, which of its various forms is most beneficial. Allegedly, throughout most of human history across the globe, sleep patterns were segmented – typically into a biphasic form (separated into two parts). This was particularly common during the late Middle Ages and Renaissance period, where having a first and second sleep during the night was the norm. In the brief peaceful waking period that separated the two, people would pray, do chores, or read by candlelight. More active individuals would engage in things like sewing or chopping wood.
This is supported by the many references to a “first” and “second” sleep, found by researchers in a variety of documents dating from the Medieval and Renaissance eras. These references, however, were also found to decrease in frequency around the 1600s. This fact seems to suggest the dwindling popularity of the biphasic sleeping form.
The 19th century is where the most change was noted, particularly with the onset of the Industrial Revolution. With rigid schedules and extremely long working conditions, people no longer had the flexibility to sleep whenever they wanted to. As a result, the biphasic sleeping form was deemed less efficient. It was replaced by monophasic sleep – which involved compressing all your sleep into one continuous cycle.
The most common form of sleep is the monophasic form, seeing as it is the most compatible with the schedules of both working adults and school-children.
Segmented schedules still persist, however, in certain parts of the world. Mediterranean and Hispanic cultures, in particular, are known for their afternoon naps – which are now dwindling in popularity.
Some individuals pursue a sleeping pattern that even includes more than two different sleep sessions. This is known as polyphasic sleep (“poly” meaning “many”), and it is incredibly rare. Research suggests that this form of sleep can help reduce the effects of sleep deprivation. It is especially helpful for those with sleep disorders, which interfere with their ability to sleep well in one complete cycle.
The science of sleep
Before we get to the most beneficial ways you can sleep, we need to first establish the science behind it. What does this process – which we’ve been doing for most of our lives, automatically, without thinking much about it – entail?
Your brain cycles through two different types of sleep. The first, known as non-REM (with REM standing for “Rapid Eye Movement”) sleep, comprises four stages. The first stage is that between being awake and falling asleep. Next is light sleep, when your heart rate and breathing are regulated. At this point, your body temperature also drops, in order to properly prepare you for rest. During the third and fourth stages, you experience deep sleep. This phase has been shown to be significant for tasks involving learning and memory, and is also the more restful and restorative phase of sleep compared to its counterpart, REM sleep.
REM sleep is the second type, and it is typically in this stage where dreams occur. During this period, the eyes move rapidly behind the lids (hence, its name), and brain waves appear much like those during wakefulness. The body becomes temporarily paralyzed, and the breath rate increases.
Together, non-REM and REM sleep form one complete cycle. A cycle alone can last anywhere between 70 and 120 minutes, before starting up again. On a typical night, one will sleep for about four to five cycles, and spend more time in the REM stage during later cycles.
How is it regulated?
There are two key ingredients to the body’s regulation of sleep: our circadian rhythms, and sleep-wake homeostasis.
The first is part of our body’s biological clocks. Circadian rhythms last roughly 24 hours and govern many of our biological processes. The most important circadian regulator of sleep is light exposure, which encourages wakefulness during the day and promotes rest at night.
The latter is a scientific term describing our body’s own hunger, or need for sleep. In biology, homeostasis is defined as the state of balanced physical and chemical conditions within the body. Sleep-wake homeostasis, therefore, is about the balance between our body’s need for rest and its need for wakefulness. This is, of course, affected by the extent of our sleep deprivation, the quality of sleep we’re getting, stress, hunger, caffeine, etc.
The necessity of sleep
It will come as no surprise, then, that sleep is a necessary part of our everyday lives – and that the consequences of deprivation can be serious and fatal.
A healthy amount of sleep is necessary for our brain’s ability to adapt to input and learn new things. Too little sleep can negatively impact our ability to process information. It can also negatively impact our ability to remember information. Rest also promotes the efficient removal of waste products from brain cells. Most notably, good quality sleep is associated with better focus and concentration. This, ultimately, has a positive bearing on whatever you do in your waking life – from studying, to conversing with a loved one.
Research has demonstrated the role sleep plays in reducing a wide range of health risks – including high blood pressure, high cholesterol, and seizures. The risks for most cardiovascular diseases can usually be reduced by regular, quality rest.
In addition, sleep is critical to the maintenance of bodily functions, the reparation of muscle tissue, and the replenishment of energy. Without it, we suffer on physical, mental, and emotional levels. It is no wonder, then, that severe sleep deprivation has been used historically as a form of torture and punishment.
Sleep: a definitive how-to guide
We’ve already discussed the definition, history, and benefits of sleep. Now, let’s get into the most important part of this article – the method. It seems, at first, a bit redundant to explain how to sleep. After all, if it’s a biological need, why would you need to have someone else instruct you? Surely, your body would know how to take care of itself?
The truth is that while the body does have its own rhythms and structures in place (like circadian rhythms and sleep-wake homeostasis, as described above), it has not adapted as efficiently to the electronic age in which we live today. Blue light, feeling constantly “switched on” to social media and work, along with many distracting apps we have on our devices mean that going to sleep is becoming a more and more impossible endeavor. As a result, we fall into dangerous habits that could severely harm us in the long run.
Therefore, this next section will cover some helpful habits you can employ to optimize your sleeping conditions – which, inevitably, will include putting your phone in “Do Not Disturb” mode, and switching off your devices. We’ll go over pre-sleep and post-sleep routines, as well as their importance, and talk about general day-to-day habits you can include to improve the quality of your sleep.
- Try not to ingest more than 400mg of caffeine a day. Caffeine, especially later in the day, can disrupt your sleep by keeping you awake later than you would like. If you can’t live without it, we’d recommend getting it in at most before 2pm.
- Exercise. Moving your body has so many benefits – as detailed in these two articles. It’s recommended that you try to finish more moderate or vigorous exercises at least three hours before bedtime, preferably even earlier. Relaxing, low-impact movements, especially yoga which focus on the breath, can be done closer to bedtime, and can help promote sleep.
- Stop eating at least two hours before bedtime. This can help prevent digestive issues getting in the way of both your sleeping time and your pre-sleep routine, which we’ll discuss in the next section.
- If you can, avoid doing activities unrelated to sleep and rest (such as work, or socializing) in your bedroom. If that’s impossible, then at least keep your bed as a sleep-only zone, so that your brain learns to associate it with sleep.
- Avoid alcohol – especially in the evenings. Alcohol interferes with your natural sleep patterns and can be detrimental to a good night’s rest.
- Expose yourself to daylight. As mentioned in previous sections, light is one of the most important regulators of our circadian rhythms. Regular exposure to daylight ensures that the chemicals and hormones in our body that are involved with the sleep process (namely, melatonin) are being produced or released at the right times. Sunlight has the strongest effect, so it would be best to open the windows, go outside, or open up your blinds. During the winter months, when sunlight is scarce, consider investing in a light box or a lamp to keep beside you during the daylight hours.
As you may have guessed, pre-sleep routines are gentle habits that you engage in to wind down before you sleep. You should typically do these about an hour and a half or two hours before your intended bedtime.
- Avoid blue light from your devices. If you must use your devices late into the night, you can invest in some blue light blocking glasses, or else turn on “night shift” in your device’s settings. This minimises the device’s production of blue light, which offsets your melatonin production and interferes with your ability to sleep. Instead, it prioritises the production of yellow light, which is less harmful.
- Gradually reduce your fluid intake before bedtime. This is important to ensure your sleep isn’t interrupted mid-cycle by the urge to use the bathroom.
- Set your thermostat to a cooler temperature. The temperature outside naturally drops during the evenings – a fact which our bodies have not yet evolved in the past. To mimic this indoors, it’s best to gradually lower the temperature of your bedroom as bedtime approaches. That’s not to say you should be freezing, but the temperature should be cool enough that you’re able to sleep comfortably, without the frustrating stuffiness of heat.
- Blackout the room completely. Any interruptions of light, yellow or blue, would disrupt your body’s regulation of sleep and likely keep you awake. With this in mind, it’s also a good idea to turn off your bedroom light earlier in the evening, and engage in relaxing pre-sleep routines elsewhere, where the light is dim. In this way, you’ll move from a lighter room to a darker room, mimicking the transition from light to dark that happens in the outdoors, and signaling to your body that once you enter your bedroom, it is time for sleep.
The purpose of post-sleep routines is to gradually wake you up and prepare you for the events and activities of the day ahead.
- Avoid checking your devices the moment you wake up. Though it may be tempting, it’s important to afford yourself the same grace and patience that you would as a child and allow yourself gradual time to adjust to the day.
- Eat breakfast. It may sound annoying to some, as the idea of eating too early in the morning is extremely nauseating. But part of your post-sleep routine includes ensuring that you have enough energy to get through the day. Even something as small as a piece of toast or a banana can go a long way.
- Drink lots of water. You’ve just spent the entire night without any fluids at all and have probably woken up parched. Thus, a fluid is needed to replenish and rehydrate your body. Drinking water is not only a necessary component to any post-sleep routine, but is also a great habit to get into.
- Gradually expose yourself to light. In your pre-sleep routine, the focus was on gradually going from light to dark. In a post-sleep routine, this should be inverted by slowly exposing yourself to sunlight. During winter, it might be best to invest in a dawn-wake simulator.
- Avoid breathing through your mouth. Breathing through your nose while sleeping increases the amount of oxygen that can be delivered to your organs and tissues, and also reduces the likelihood of disruptive issues such as snoring, salivating, and shallow breathing. Certain conditions, such as sleep apnea, make breathing through the nose while sleeping difficult – in which case, it is necessary to see a medical professional. In most cases, however, you can avoid this issue by doing regular breathing exercises, or even mouth taping (which you can read more about here).
- Pay attention to your sleeping position. Since this is the position you’re likely to hold for most of the night, it’s important that it’s comfortable and harmless for your joints, your neck, and your back. Though some like to lie on their stomachs, this is one of the most dangerous positions because it places too much pressure on the neck. Littlehales recommends that you lie in a fetal position on your non-dominant side (if you’re right-handed, this would be your left side; and vice versa).
- Don’t stress too much if you wake up. Though sleep is best when uninterrupted, sometimes things happen to keep us awake – stress, nightmares, or a simple need to use the toilet. If you find yourself lying awake in bed for longer than 20 minutes, don’t force it. Instead, get up and engage in one of your calming pre-sleep activities until you feel the urge to sleep again.
Other important tips
- Determine your chronotype. Your chronotype is, essentially, whether you’re an early bird or a night owl. Using this information, you can then organize your day around your chronotype as best you can. For instance, choosing to do social activities later in the evening if you’re a PM-er, or signing up for morning classes if you’re an AM-er.
- Set a regular wake-up time. On average, Littlehales recommends that you plan to get in about five sleep cycles per night (he defines each cycle as roughly 90 minutes). Once you set a wake-up time, work backwards in cycles to see at what time you should sleep in order to get to five. For instance, if you need to get up at 8:30, then five cycles before that would be about seven and a half hours. This means that you’ll need to be in bed by at least 1 a.m.
- Avoid sleeping in—even on weekends. Consistency is one of the most important parts of a good routine. Our bodies, not yet adapted to the fast-paced world we live in, thrive on a schedule that we are able to maintain consistently.
- Keep a sleep journal. Like any habit, there’s no disadvantage to tracking your sleep and staying mindful of what the best conditions and hours are for you. Each body is different, after all. Littlehales recommends noting down the number of cycles you get each night and obtaining a weekly total. The average is 35 – as long as you meet that number, you should be fine.
If you didn’t manage to meet five cycles at night, not to worry. You can still make up that debt by taking naps. Though culturally frowned upon, there’s nothing wrong with an energizing power nap – as long as you do it properly. If you nap for too long, or too late in the day, it might have adverse effects. Ultimately, this could impact your ability to rest later that night.
The best nap time is between 20-30 minutes at a time. Although you can nap at any time, there are some hours that are better for rest than others. One of these is between 2 and 3 pm – also known as the “post-lunch dip”. This mirrors its nighttime counterpart, 2-3 am, which is the hour of deepest sleep and lowest body temperature.
If possible, avoid taking naps in your bed. You should associate your bed with full deep sleep – the kind you should ideally be getting at night. Taking naps there too frequently may force you to associate it with the light, easily interrupted naps instead. This, in turn, would lessen the quality of your nighttime rest.
It’s unfortunate that we live in a society that puts rest at the bottom of its list. But the fact that this function is largely ignored doesn’t take away from its immense significance in our lives. Like eating, moving, and breathing, we do it for a reason. And with careful tracking, mindful habits, and, above all, consistency, there’s no reason why any of us should have to struggle with sleep.