The Science of Sleep and Why It Is So Important To Our Health

By Rachel Hanrahan


Why Sleep is so important?

Even though we often don’t remember much of our sleep, we will spend about a third of our life in this state. Sleep occurs when your body and brain drop into an unconscious, restorative state.  Sleep can do incredible things for you.  Whilst sleeping your body can rest and perform some essential maintenance on your memory, hormones, your immune system and other critical functions that improve your wellbeing. Sleep improves the brain’s ability to learn, helps the body fight infection, allows your heart to rest and can even lower blood pressure.  What a panacea.

Not getting enough sleep can have adverse effects on our health.  There is no aspect of our biology left unscathed from sleep deprivation.  Without sleep we have low energy and disease.  With sleep there is health and vitality. While you’re sleeping, many of your body’s basic functions are altered or suspended allowing other specialised functions to happen to remedy what our body, nervous system and mind need. We now know that during sleep our brain actually cleans off an amyloid plaque that builds up on our neurons from normal day to day metabolism. There is often a build of neuron plaque for those with Alzheimers and Dementia so there seems to be a direct correlation between brain health and the amount of deep sleep.

How much sleep do you need?

The amount of sleep someone needs is highly individual.  Adequate sleep is a vital component of good health. According to sleep scientist Matthew Walker, ‘anything less than 7 hours is sleep deprivation’. Sleep and rest are known to be a time for the body to repair and regenerate itself. During sleep the spine regains its flexibility, the skin makes repairs, the muscles clear lactic acid and the immune system recovers. During sleep the body produces Human Growth Hormone which plays an important role in deterring aging and disease processes.

Deep sleep – the part when we begin to dream – is a therapeutic state during which we cast off the emotional charge of our experiences, making them easier to bear. Sleep, or a lack of it, also affects our mood more generally. Brain scans carried out by Sleep scientist Walker revealed a 60% amplification in the reactivity of the amygdala – a key spot for triggering anger and rage – in those who were sleep-deprived.

So not all sleep is created equal. We sleep in 90-minute cycles, and it’s only towards the end of each one of these that we go into deep sleep. Each cycle comprises two kinds of sleep. First, there is NREM sleep (non-rapid eye movement sleep); this is then followed by REM (rapid eye movement) sleep. During NREM sleep vast amounts of memory processing is going on.  Your body settles into a low state of energy with regulating blood-pressure. REM sleep sometimes known as paradoxical sleep, because the brain patterns are identical to when you’re awake. It’s an incredibly active brain state. Your heart and nervous system go through spurts of activity. You need 90 minutes to get to deep sleep, and one cycle a night is not enough you need four or five cycles to get all the benefit.

How can we work with energy practices to prepare us to access the deep sleep healing states? Deeper Sleep is a 10 week journey exploring ancient energy techniques such as yoga nidra, qigong and healing sounds combined with the modern understandings of polyvagal theory, sleep rhythm and sleep drive.  Through the course you will develop an understanding of how to best work with your energy on a daily basis that sets the preparatory foundation for deep soothing sleep.

Join Rachel Hanrahan on Sundays 7pm from March 6 to deepen your quality of sleep. Qigong Sequences, yoga nidra recordings are all accessible for you to continue your healing journey post course. For more information and to book online, go to: