Why We Sleep
There is not exactly a consensus on the evolutionary origins that give rise to our need for sleep.
Some have theorised that, way back when, it might have thankfully kept us immobile in a highly predator prone landscape (especially at night when our vision is perhaps not lent to such forays).
However many studies showing the negative health effects of missed sleep, suggest that there is a far more essential biological function to sleep, that does not allow us, in today’s largely predator free urban existence, to just skip sleep altogether for want of a more action packed lifestyle (although many of us do try).
Instead it has been suggested that we have a very indispensable need to process and organise our thoughts and experiences from the day, into ‘integrated’ perceptions, memories and ‘notes to self’ (i.e retaining what was useful, and discarding what was not).
The classic analogy is similar to that of a computer hard drive ‘defragging’ itself every night before you come back to work – so that it can be less cluttered and ultimately function more nimbly and appropriately, having everything you need ‘on file’ and ready to go as the situation almost preemptively arises (yes technology like that would be very sweet to own wouldn’t it?)
Well guess what?.. you got it!
If you sleep that is.
Why Sleep Is So Important
Sleep is one of the single most important lifestyle factors determining your health.
It is during deep sleep stages (particularly between 2am and 6am), that your body’s core temperature drops and nervous system repair and recovery takes place along with numerous other cellular and metabolic maintenance processes.
How does your body know when it is 2am you might ask?
We’ll get to that in just a minute.
You need to get your sleep if you are going to enjoy some of the following benefits:
- Increased energy
- Reduced stress and anxiety
- Improved mood and positivity
- Increased alertness and life engagement
- Less ‘brain fog’
- Fast/better recovery from exercise, stress or illness
- Improved immunity and resistance from surrounding infections
- Ultimately.. increased ‘resilience’
So what are the downsides of NOT getting enough sleep?
- Hunger dysregulation
- Fatigue and poor exercise performance/capacity
- Increased risk of Weight Gain
- Increased risk of Heart Failure
- Increased risk of Irregular Heartbeat
- Increased risk of High Blood Pressure
- Increased risk of Stroke
- Increased risk of Diabetes
- Increased risk of Mood Disorders
- Increased risk of Cancer
To name just a few of the indications that modern research is revealing…
Your ‘Eat-Sleep-Wake’ Cycle
Over the past two decades we’ve learned a great deal about the inner workings of the ‘circadian clock‘, the internal timepiece that controls our ‘sleep:wake cycle’ and in the process we have found a whole host of other daily bodily rhythms are connected to it, such as the metabolic, adrenal and sexual hormone systems, to name only a few (but very very important) players.
This ‘clock’ is housed in the central nervous system (i.e. your brain), where it attempts to synch up with surrounding light cues via your eyes (not your skin, as was recently suggested), to determine what is ‘day’ and what is ‘night’, so that it can coordinate (directly and indirectly) almost every time-sensitive process in your body, according to this apparent daily schedule.
Here is what a breakdown of the cycles that occur in a night’s sleep, along with a breakdown of the stages within one of those cycles, look like.
Notice that Rapid Eye Movement (REM) sleep actually involves an increase in brain activity, almost akin to being awake. It makes sense why dreams might sometimes feel so lucid. All that activity is not cheap to the body though, which reinforces the idea that REM has some very essential roles to our health and wellbeing.
Therefore it is now known that many many symptoms and disorders are likely to be exacerbated and perpetuated by any dysregulation of this clock, especially those that affect metabolism and hormone balance.
It is for this reason that it could also perhaps be better described as our ‘EAT-sleep-wake cycle‘, since it is these same systems in the body that regulate our scheduled cues for hunger at certain times of the day (when your body is ‘accustomed’ to receiving food), as do so for sleep.
Your body is actually constantly making adjustments to various hormones in an attempt to prepare the body appropriately for wherever it thinks is coming up next in that schedule.
The Exercise Block
In fact, by acknowledging this, we could now even say that we have an ‘EXERCISE-eat-sleep-wake cycle‘ (so long as we took a deep breath beforehand), because beyond the existing research that shows us a chicken and egg scenario, (where not only does your level of exercise effect the quality of your sleep, but also that the quality of your sleep effects your capacity for exercise), some research from Brazil shows us an additional refinement to this, namely that it is also the ‘time of day’ your body feels it is at (based to a large degree on this same sleep:wake light cycle) that also determines some of your exercise capacity.
Essentially, exercise performance and spontaneous locomotor activity were both found to be strongly influenced by daily cycles of light and dark.
So you get the picture, your circadian rhythm is pretty much your ‘everything cycle’, when it comes to orchestrating your health.
Which makes sense since ‘circa’ (meaning ‘about’) and ‘dia’ (meaning ‘day’) in Latin, makes ‘circadian’ simply mean the ‘about-a-day’ cycle (i.e. everything your body coordinates and regulates in a 24 hour period – including light and dark, activity and rest).
There should be no surprises that it affects so much.
And what power lies in harnessing it by harmonising it?!
Numerous hormonal and metabolic effects of poor sleep (and/or high stress) have been observed. Largely attributed to their uniting feature of Cortisol over-production.
When Cortisol is being over produced, Melatonin cannot exert many of its calming and restorative effects, (i.e. through sleep).
So perhaps it should not be as surprising as it is, that the circadian cycle, being so heavily influenced by light exposure, has been shown to have a direct connection with body weight in this research from the Northwestern University Feinberg School of Medicine, which showed that only “about 20 to 30 minutes of morning light is enough to affect BMI” and concluded that “the later the hour of moderately bright light exposure, the higher a person’s BMI”
So ‘lay-ins’ could mean kilos, simply through dysregulated light cues (regardless of how many actual sleep hours were banked)!
Further to all of this, recent research in the Journal of Molecular Biology of the Cell has found that the protein called ‘human period 2‘, that is essentially responsible for regulating the body’s circadian rhythm, also protects the body from developing sporadic forms of cancers.
Specifically, researchers have found that when left unaltered, the ‘human period 2’ protein directly interacts with ‘tumor suppressor’ proteins in cells to actively control cell division.
However the cellular function of this very special protein is ‘impaired’ when environmental factors, including sleep cycle disruption, are altered or disrupted.
When this protein is unable to do its job and prevent the cells from dividing at certain times of the day, Tetsuya Gotoh a lead author of this research states that “this is particularly a problem in cases where tumor suppressor genes are mutated, as it happens in more than 80 percent of all cancer cases.”
Results from these studies may therefore help develop new, more effective prevention strategies for populations at risk due to circadian disruption, (such as women working night shifts – which just as an example, has been shown in research by Carla Finkielstein and others, to correlate with an increased incidence of breast cancer in women who work night shifts (like nurses and flight attendants).
Depression & Anxiety?
Repetitive ‘negative thoughts’ have been linked to late evenings.
When you go to bed and how long you sleep at a time, might actually make it difficult for you to stop worrying, according to recent researcher at Binghamton University.
This study by Coles and Nota in Springer’s journal Cognitive Therapy and Research, found that people who sleep for shorter periods of time and go to bed very late at night are often overwhelmed with more negative thoughts than those who keep more regular sleeping hours.
People are said to have ‘repetitive negative thinking’ when they have bothersome pessimistic thoughts that seem to repeat in their minds without the person feeling as though they have much control over their contemplation.
Previous studies have linked sleep problems with such repetitive negative thoughts, especially in cases where someone does not get enough shuteye.
So whilst correlation doesn’t necessarily mean causation in all these cases, Nota states “Making sure that sleep is obtained during the right time of day may be an inexpensive and easily disseminable intervention for individuals who are bothered by intrusive thoughts,” according to Nota.
Which emphasizes not only the amount of sleep we get, but again that it is the regularity (aka rhythmicity or predictability) of our circadian sleep:wake cycles that is required in order to maintain optimum health, (including mental wellbeing).
The bottom line is that we all need to prioritise precious sleep – as busy as our modern schedules may be.
After all, sleep can increase our productivity, decrease the stresses that are likely to be interfering with it in the first place, and ultimately allow our quality of life to reach a whole new level.
Even when we are drawing on fist fulls of pills and other therapies to compensate for ailments that are often, at their heart, heavily influenced by sleep deprivation.
Or when we could otherwise be unwittingly increasing our risks of many more serious disease concerns than we might have first imagined.
Through chaotic and dysregulated lifestyles, we may be overlooking the sweet assistance provided by some simple good old fashioned sleep.
How Much Sleep Do We Actually Need?
According to the Centers for Disease Control and Prevention, 30 percent of (employed) adults are frequent ‘short sleepers’ (regularly sleeping 6 hours or less per night).
Whilst the American Academy of Sleep Medicine recommends that adults get about 7 to 9 hours of nightly sleep for optimal health, productivity and daytime alertness.
Yes, you can get too much of a good thing (regularly getting much more than 9 hours sleep as a general habit has been shown to not necessarily be a good thing for your health). But don’t deny yourself what your instinct demands after a particularly busy or sleepless period, your body may need more rest for certain periods of time and will quickly find a healthy equilibrium back within the 7-9 hour range if no further obstructions to proper rest exist and once you have recovered from the immediate deficit (although note that unfortunately it is not so easy to address a long standing ‘debt’).
This guideline has no-doubt contributed to the often recommended cliche of ‘8 hours’ widely regarded as the ‘ideal’ or most appropriate amount of sleep, however this is more of a generalisation or ‘average’ between the 7-9 hour range than a magic number. As with all things in health, there is no fixed number of sleep hours that every individual must universally achieve to be healthy.
Even the 7-9 hours may be a generalisation. The amount of sleep hours any one of us should get depends on the age and needs of our body. For example an infant sleeps up to 16 hours a day, whilst a senior adult may only require four or five hours. If however you are a fully grown post-adolescent adult and you have notable demands on your body and mind (which all of us should probably have to some degree, if we are living a life fully engaged with our potential) then the 7-9 range probably applies to you (whether you’ve adapted to less or not).
What matters most however, is the QUALITY of your sleep.
So How Much Do YOU Need?
Tip: Experiment with the amount of hours that make you feel most rested and respect that time. Because what we tend to do in our busy lives is sleep only as a last resort, (once we have already incurred a deficit), and only if we have the time, or the circumstances to ‘allow’ it. But harnessing all the benefits and risk reductions discussed above, is going to mean getting proactive in order to protect this essential platform to your personal potential.
So why don’t we get it?
Our Biggest Problem
This TED talk by Kirk Parsley is quite possibly.. no you know what, I am going to say it is definitely.. the best summary I can suggest anyone ever watch to get a sound perspective of how important sleep is to our physical and mental wellbeing (and therefore our potential), as well as, most crucially, why we often still dont get it.
I highly recommend you spare the 15 minutes to experience these potentially life changing observations.
There are few things higher on your list of priorities for supporting your highest personal potential than sleep.
Sleep is perhaps only second to breathing in terms of its immediacy to our needs. So why do we let so much get in the way of it? (Im not sure we would be as permissive of something that was obstructing our breathing – so perhaps we should not be fooled by the more insidious time-scale).
The choice is each of ours alone, to either ‘buy into’ the current modern social norms (that may have drifted well beyond all reasonability of what we can expect from ourselves and others, and may not even deliver what they set out to in the first place in terms of performance or productivity), or ‘yield’ to the inner messages written in our genes, along with the physical realities of living a fully engaged life, and give ourselves (and those around us) more of what we need and deserve.
Give yourself the permission to get your optimum rest, in order to live life as your most vibrant self.
Dream on I say.