THE IMPORTANCE OF SLEEP PART 1
Sleep is of the utmost importance. We need 8 hours of quality sleep every night.
How often do we hear this? It’s been drilled into us for as long as we can remember, and yet most of us still don’t take heed. Why is sleep so important? What happens during sleep and what really happens when we don't get enough? Read on to learn about the effects of sleep deprivation and how we are all missing out on something so simple as sleep, that can truly enhance our lives.
Eat Sleep Wake Repeat. The hum drum of our lives. For so many of us we wake tired, sleep walk through the day, ply ourselves with endless cups of coffee, go to bed late, and we survived another day. This is our state of norm. We know if we got more sleep we would probably feel better, perform better, or even just be in a better mood. Yet we don’t prioritise sleep. Instead we want to be awake for longer to get more out of the day, be more production, or we just have FOMO (fear of missing out). But how productive are we really given that lack of sleep makes us feel terrible? What enjoyment can we really get from our day when we don’t feel 100%? It’s crazy that we think it’s ok to leave for work in the morning half charged, feeling tired and under par, but not ok to leave with only 50% battery on your mobile phone. We place more importance on having a fully charged well-functioning phone and connecting with the world from behind a screen, than we do on being our fully charged well-functioning selves in the flesh.
Some people really are just unaware of how much they are affected by the lack of sleep and simply acclimatise to these low levels of functioning as their state of norm. For others it can be a “I’ll sleep when I’m dead” mentality. Like with most things, when we don’t see any significant negative consequences to our actions, or we can’t quantify these consequences, it’s easy to disregard its importance. So you didn’t get 8hrs sleep last night, but you’re still living, breathing, and getting on with the day, what’s the big whoop?
There’s a bigger whoop than you realise when you start to understand the function of sleep, and how sleep deprivation can significantly affect your cognitive function, health, quality of life, and ultimately your lifespan. Or to put it in a less scaremongering way, understanding how quality sleep can drastically enhance our lives, from physical energy and wellbeing, to better memory and learning, enhanced mood and emotional stability, balanced appetite and satiety, and even muscle building and fat loss.
Understanding what happens when we sleep is a good first step to appreciating its importance.
TYPES OF SLEEP AND KEY FUNCTIONS
We have 2 types of sleep that cycle over 5 stages over the duration of the night:
NREM (Non-Rapid Eye Movement) Sleep
Stages 1-2 are the transitional stages from wakefulness into light sleep. In these stages we can be woken easily and have fragmented memories of dreams. Sleep spindles (sudden spikes of brain wave activity) can also be seen during stage 2.
Stages 3-4 are referred to as deep sleep where brain wave activity slows and we dive into a deeper slumber. It is hard to wake someone in these stages and when they do they can feel groggy and disorientated.
REM (Rapid Eye Movement) Sleep
Stage 5 REM sleep shows highly active brain waves similar to when we are awake. However, the body is in full paralysis and accompanied by rapid eye movement. During this sleep our heart rate and blood pressure elevates, breathing becomes more shallow and rapid, and we often experience the more bizarre dreams in this stage. It is believed that our bodies are paralysed during REM to prevent us from acting out our dreams.
Over the course of the night we cycle through these 5 stages about every 90 minutes. During the first half of the night we experience a higher proportion of NREM sleep than REM, and as we head into the early hours of the morning it switches so we have more REM than NREM.
This makes sense as one of the main functions of NREM sleep is to process and store new information, and removing any unnecessary neural connections, so that the remaining neural connections can be strengthened during REM sleep. Consider wakefulness as a state of information reception where our sensory gates are open wide to take in new stimulus. NREM sleep is the clearing out of the short-term memory cache, sorting out what facts and skills need to be retained and stored into long-term memory. And REM sleep integrates the new facts and skills with past experiences, memories and emotions, helping to round out the information to build a more accurate understanding of the world, and allowing for creativity and problem solving.
Having adequate sleep before learning new information helps to refresh the brain and its ability to make new memories. We have a limited capacity to retain short-term memories and NREM sleep helps us to move these memories into long-term storage and free up space for new memories. Having adequate sleep (both deep NREM and REM) after learning helps to strengthen and consolidate these new memories and skills. So when we shorten the duration of sleep, we reduce our capacity for learning of fact-based information, motor skills, and creative thinking and problem solving.
When we have shorter periods of sleep, the loss of NREM and REM is not equal as the proportion of each type of sleep changes over the duration of the night. If we stay up later than our natural circadian rhythm dictates, we get less NREM sleep, and if we cut short our sleep by waking up too early before our circadian rhythm picks up pace, we get less REM sleep. To add to the imbalance, when we try to make up for the missed sleep, over the first few nights of recovery we will have more deep NREM sleep, and only after a few more recovery nights do we soak up more REM sleep. So simply catching up on sleep at the weekends isn’t as effective in sleep recovery as we think it is.
WHAT ARE THE EFFECTS OF SLEEP DEPRIVATION?
We take sleep for granted but we are far more dependent on sleep than we realise. Sleep affects our physical wellbeing from our health to our nutrition, cognitive function including memory, logic, and linguistics, and our behaviour and emotional wellbeing. It also impacts us on a social, economic, and organisational level.
HOW DOES LACK OF SLEEP AFFECT THE BRAIN?
Studies have shown that after 16hrs of being awake, the brain starts to decline in performance. To maintain good cognitive function we need more than 7hrs of sleep a night. Some of the obvious cognitive effects of sleep deprivation are:
REDUCED CONCENTRATION
It is much harder to focus and pay attention when we are sleep deprived, and we often experience ‘microsleeps’, where we have moments of feeling ‘spaced out’ and not being present.
SLOWED REACTION TIME
A lack of sleep can drastically and dangerously slow your reaction time especially when driving. Sleep deprivation can cause the same level of decreased function and reaction as drinking alcohol.
REDUCED LEARNING ABILITY AND MEMORY
As discussed earlier, NREM sleep helps us to store information into our memory banks and REM sleep consolidates this information with past experiences, adding more context to the information. Without sleep not only do we struggle to make short-term memories into long-term ones, but with the lack of concentration it makes it even less likely to retain the short-term information in the first place. In order to create strong memories, we need both adequate sleep before and after the learning event.
LACK OF CREATIVITY
Without REM sleep our abilities for higher level thinking, problem solving, creativity and innovation are reduced.
EMOTIONAL IRRATIONALITY AND IMPAIRED JUDGEMENT
Sleep deprivation can alter your mood significantly. It can cause extreme mood swings, strong emotions such as anger and rage, can exacerbate stress, and is linked with anxiety, depression and other mental health conditions. It is not yet known whether lack of sleep causes mental health disorders or mental health disorders causes sleep conditions, but the 2 are closely linked. With adequate sleep the pre frontal cortex in the brain, that is our rational centre and controls logic and decision-making, balances with our primitive instincts and our fight or flight response to situations. When we are sleep deprived, we no longer have that balance and are unable to control our reactions in as measured a way, causing inappropriate emotional responses.
HOW DOES LACK OF SLEEP AFFECT THE BODY?
Our bodies operate under the control of our internal clock known as the circadian rhythm. As the sun rises our body clocks begin to wind up and winds down as the sun sets. This sleep/wake cycle controls and regulates hormones to activate various systems within the body at set times over the course of the day. When this sleep/wake cycle is disrupted, so too is the regulation of these systems which can cause a multitude of physiological effects.
During deep NREM sleep our bodies turn on its parasympathetic nervous system that provides an environment for rest, restoration and growth. Lack of sleep however, stimulates our sympathetic nervous system that keeps our bodies in fight or flight mode, keeping us on high alert to respond appropriately to stressful situations. Constantly being on high alert increases our heart rate, breathing rate, blood pressure, and release of cortisol (stress hormone). With the body anticipating imminent danger, systems that are unimportant in the current need for survival are down regulated and can lead to health conditions and complications such as:
CARDIOVASCULAR DISEASE
Having unhealthy sleep can lead to having an unhealthy heart. Deep NREM sleep is our natural blood pressure management system as it turns on the parasympathetic and turns off the sympathetic nervous system. As mentioned earlier, with poor sleep and an overactive sympathetic nervous system, we have elevated heart rate, blood pressure, and cortisol that contribute to constricting of blood vessels, further increasing blood pressure. Without sleep and the activation of the parasympathetic nervous system, we cannot repair the increasingly damaged blood vessels, leading to strokes, heart attacks, and other heart related diseases.
OBESITY AND DIABETES
The low levels of energy we feel after having too little sleep affects our metabolism. Having low energy inadvertently reduces our level of physical activity, therefore decreasing our daily caloric expenditure which can contribute to weight gain or a lack of weight loss. In addition to being less active we have a tendency to eat more when sleep deprived. As mentioned earlier, lack of sleep affects our judgement, so food impulses become harder to control and we crave high carb high calorific foods to satisfy primitive instincts of pleasure and desire. Combine this with increased hunger with the rise in the hunger hormone ghrelin, increased endocannabinoids that affect appetite, and a decrease of leptin our satiety hormone, we are more likely to over eat when sleep deprived. To make matters worse, lack of sleep and the high levels of cortisol can cause insulin resistance in our cells that affects blood glucose regulation, leading to excessive fat storage and diabetes.
GUT HEALTH ISSUES
Bacteria in our gut known as our microbiome is regulated by our circadian rhythms. When our sleep is disrupted so too is our microbiome causing various digestion and gastrointestinal issues, other immune conditions, and can affect cognitive function. Gut health issues can be uncomfortable which can then affect the quality of our sleep creating a loop of dysfunction.
PROBLEMS WITH THE REPRODUCTIVE SYSTEM
An overactive sympathetic nervous system down regulates our reproductive systems and can cause decreased sex hormone activity, including low levels of testosterone, sperm count, and sperm deformities in men, and abnormal menstrual cycles, ovulation and conception in women.
COMPROMISED IMMUNE SYSTEM AND CANCER
Without sleep we cannot heal. Our immune systems have a two-way relationship with sleep. When we sleep our immune system is able to fight infection and create anti-bodies, and when we are ill, our immune system stimulates our sleep system and parasympathetic nervous system, allowing us to rest and recoup. Sleep deprivation and an overactive sympathetic nervous system increases inflammation in the body that can keep the body’s immune system on high alert, causing it to attack healthy cells and develop autoimmune conditions. Sleep deprivation and prolonged inflammation can reduce the body’s ability to kill cancer cells while feeding tumours and further damaging DNA.
Having learnt about the benefits of sleep and the effects of sleep deprivation, how well do you rate your sleep now? Answering YES to any of the questions below is already an indication that your sleep could be improved:
Do you regularly sleep less than 8hrs?
Do you go to bed after 11pm?
Do you wake up before 6am?
Do you have trouble falling asleep?
Do you wake during the night (including to go to the toilet)?
Do you struggle to wake in the morning?
Do you wake tired and your energy stays low for the rest of the day?
Do you need caffeine to wake up?
But whether you answered yes or no to any of these questions, one of the best ways to assess whether you’re getting enough quality sleep, is by how you feel both physically and mentally.
Check in with yourself and ask yourself:
Do you think your daily energy and performance is where you would like it to be?
Do you feel your memory isn’t as good as it could be or do you lack concentration or creativity?
Do you find yourself regularly feeling sub-par and under the weather, stressed, depressed, angry and short fused, insatiably hungry, or struggle to lose weight?
Do you feel tired throughout the day and yet still struggle to fall asleep at night?
And the next question and observation to make is:
How much better do you feel after getting a good night’s sleep?
We all know this to be true. We feel better, feel refreshed, and think clearer after long restful sleep. Imagine what your life would be like if you felt like that every day! Recognising the importance of sleep and prioritising it is the best thing you can do to help enhance your life. By implementing some simple sleep practices you can improve your health, boost you brain power, elevate your mood, and increase your energy and productivity levels.
I’ll be posting Part 2 of this blog soon with my Top Tips to Improve Your Sleep so you can clean up your sleep hygiene and learn how to sleep well and enhance your life. Stay tuned.