The Science of Sleep

by Dean McKillop 1820 views Lifestyle

The Science of Sleep

Some people need their partner next to them, while others like the solemn sweetness of an empty bed to themselves. Then there is the consideration for curtains being pulled closed or open to the moonlight, having nightlights on your side table, using external noise to calm your thoughts or even pre-bed meditation. Regardless of what your current preference of sleep environment is, understanding the science behind sleep can help you improve your environment even further.

It was long accepted prior to the research we now follow that sleep was a momentary ‘shut down’ of the body. People thought your metabolism ceased, your body ‘went to sleep’ and everything went into shutdown.

This couldn’t be further from the truth…

While our biological systems of the brain, the body, and the digestive system may slow in critical times of sleep, they most certainly do not ever stop.

In fact, during sleep, the body actually increases restoration and recovery through active methods, of which when you are in your most restorative state, certain functions such as your heart rate, your breathing, your brain activity and your eyes actually increase their activity.

Why is all of this important to know? Because quality matters!

To date, there are 5 Primary Phases of Sleep that occur during a standard night of sleep.

The 5 Primary Phases of Sleep

Phases 1 - 4:  The semi restorative phase!

Phases 1 - 4 of your sleep pattern are known as Non Rapid Eye Movement (NREM) sleep, whereby they generally follow a sequential fashion of initial short duration sleep (mini nap), to a slightly deeper sleep (power naps) and finally to stages 3 and 4 are where you begin to reach a deeper sleep.

In Phases 3 - 4, restoration begins to occur, however, your body ‘slows’ in this moment as opposed to speeding up, you become less responsive to outside stimulus and you become ‘prepared’ for true restoration to come.

Think of phases 1-2 as your napping phases and 3-4 as your preparation phases.

Phase 5: The restorative phase!

Phase 5 is the sleep pattern most people refer to when it comes to true restoration. Known as Rapid Eye Movement (REM) sleep, REM is your primary restorative phase of sleep where neuronal activity increases, eye twitching begins, heart rate and blood pressure rise and dreams are experienced.

This is the phase of sleep we refer to when discussing quality.

Most people manage to reach REM sleep within the first 2 hours of their sleep phase, assuming their environment is supportive of deep sleep and it can last between 20-60minutes per phase and repeated upwards of 5 times each night depending on the total length of your sleep phase.

REM is when your brain consolidates on what information it has received in the day and attempts to ‘log it’ in your long-term memory bank for retention.

This is true restoration and is critically important in ensuring your body has the opportunity to repair, rebuild and restore.

The Chemistry Of Sleep

We have two primary chemicals the brain relies on for feedback on sedation / sleepiness, with those being Melatonin and Adenosine.

Think of Adenosine as an accumulative sedative and Melatonin as the switch for sleep initiation. Throughout the day, levels of Adenosine begin to rise, being taken up by cells in the brain that are responsible for releasing excitatory neurotransmitters that improve wakefulness. As the day progresses, Adenosine levels increase and a feeling of sleepiness occurs.

coffee

Yes, that’s part of the 3pm slump…

It’s also the reason why caffeine keeps us awake, as caffeine is an Adenosine receptor antagonist, meaning it blocks the build up of Adenosine in the brain.

Melatonin, on the other hand, relies on environmental factors to stimulate its production and release. Feedback systems that rely on the retina in the eye, respond to light signals, sending messages to the brain that sunlight is still available and Melatonin production is impeded.

Melatonin is a sleep inducer, so production during daylight would be counterproductive to survival.

As the sun begins to set and darkness increases, feedback on the level of light is sent to the brain via the retina and tells a small gland in the brain known as the pineal gland to release Melatonin.

Melatonin then begins the process of inducing tiredness, sedation and initiating sleep. Essentially, without Melatonin, you are going to have a hard time sleeping.

Which brings me to the message of this article and using the understanding of sleep science to enhance your recovery.

Melatonin traditionally works on a daily release schedule known as a circadian rhythm (lots of hormones are also released in this fashion), however, it can only do so when all external environmental factors are controlled.

Which is where the problem of living in 2017 begins to impact our lives…

We are constantly under bright lights, constantly involved in excitatory activities prior to sleep, constantly staring at bright screens and our levels of stress are generally too high in order to allow for adequate relaxation.

All of these things one way or another impact melatonin production as we miss the natural release patterns due to external intervention.

We don’t follow the natural circadian rhythms of sunrise and sunset.

But can we fix this?

Sure we can… and we can do it two-fold.

  1. Fix the environment
  2. Enhance the process

Let’s look at the environment first…

The number 1 rule to follow when it comes to improving your sleep environment is to minimise or remove excitation close to your proposed bedtime. This means removing light exposure of all kinds, anything that requires intense mental focus and minimising stress.

I have outlined this further here - 5 Steps To Better Sleep.

Nail those 5 steps alone and I can almost guarantee your sleep quality will improve. But what else can we do? You ready for this? Eat some carbs at night… YES!!!!!

Now, this doesn’t give you free reign to eat a big bowl of ice cream or cereal without consideration for the calories you are about to consume, but it can potentially improve your sleep.

Why should you eat carbs?

Ever experienced a ‘carb coma’? You know the times where you hammer a bunch of carbs and then get super sleepy after the fact. Well, that feeling makes sense when you understand the cascade affect post carbohydrate consumption.

You see…Melatonin requires serotonin > serotonin is created from 5-HTP > 5-HTP is created from Tryptophan.

pasta

The two primary food groups that provide Tryptophan from natural sources are mainly protein and carbohydrates. However, the interesting thing about carbohydrates is they also provide a large dose of circulatory glucose, which when signaled to be stored by Insulin, Tryptophan is left over in the bloodstream in large quantities, making it available for neurotransmitter biosynthesis.

In short…After consuming a tonne of carbs you are left over with a large amount of circulating tryptophan, which then has the potential for a creating a surge in serotonin release and consequently sleepiness.

Plus they are delicious. Did I also mention carbs are delicious?

Ok back to the topic at hand. Let’s wrap this thing up…

By understanding the science of sleep, how your hormones responsible for sleep are impacted by your environment and utilising carbohydrate backloading (eating them at the back end of the day) you can manipulate your approach to sleep in order to improve it.

Ensuring you achieve maximum REM sleep on a regular basis is critically important for maintaining healthy physiological function, which in turn leads to both an improved speed and quality of results.

If sleep is poor, the rest of your life will be also.

Don’t underestimate the power of recovery. 

Dean McKillop

Exercise Scientist

I completed my Exercise Science Degree at the University of QLD and have worked in the fitness industry for over 8 years, including a short stint at the Brisbane Broncos in 2010 as a student. I also hold my Level 2 Strength and Conditioning Coach accreditation (ASCA) and have competed in 1 bodybuilding season, placing 2nd at the IFBB u85kg Nationals.

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