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The Power of Sleep

We all know how it feels when we don’t get enough sleep and sometimes it might be necessary to look at our ‘bedtime routine’ (yes, adults as well as children need a good sleep routine!) to make sure it is giving us the best possible opportunities to get optimal sleep time.

Sleep is an essential function that allows your body and mind time to recharge in order to leave you refreshed and alert when you wake up. A good sleep routine can also help our bodies remain healthy to stave off diseases. Without enough sleep, the brain cannot function properly (groggy brain sound familiar?) and this will in turn impair your ability to concentrate, think clearly and very importantly, process memories.

Typically, most adults need around seven hours sleep a night. Children and teenagers need substantially more to promote healthy growth. There are many disrupting factors that can prevent good sleep patterns such as our busy school/work schedules, the day-to-day stresses of business and home/family, too much technology, too much light, too much (and too little) food, drugs & alcohol and some medical conditions. All of these can prevent us from receiving adequate amounts of sleep.

The Science Behind Your Sleep

We all have an internal “body clock” which regulates your sleep cycle, controlling when you feel tired and ready for bed or refreshed and alert. This clock operates on a 24-hour cycle and is known as the circadian rhythm. After waking up from sleep, you will become steadily more tired throughout the day and this feeling will peak in the evening leading up to your bedtime.

This drive each day towards sleep – also known as sleep-wake homeostasis – may be linked to adenosine which is an organic compound produced in the brain. Throughout the day adenosine levels increase and signal to the body that it’s time to sleep. During sleep your body then breaks down this compound and it is cleared from your brain.

Light also influences the circadian rhythm. The brain contains a special region of nerve cells known as the hypothalamus and a cluster of cells in the hypothalamus called the suprachiasmatic nucleus, which processes signals when the eyes are exposed to natural or artificial light. These signals help the brain to determine whether it is day or night.

As natural light starts to disappear in the evening, the body releases melatonin, a hormone that induces drowsiness. When the sun rises again in the morning, the body releases the hormone known as cortisol which is responsible for promoting energy and alertness.

The Different Stages of Sleep

Once we have fallen asleep, our bodies follow a sleep cycle that is divided into 4 stages. The first three stages are known as non-rapid eye movement (NREM) sleep and the 4th stage is known as rapid eye movement (REM) sleep.

  • Stage 1 /NREM: The first stage typically lasts several minutes. It marks the transition between wakefulness and sleep and consists of light sleep. During this stage your muscles start to relax and your heart rate, breathing and eye movements begin to slow down. Your brain waves also start to slow down during stage 1.
  • Stage 2 /NREM: Stage 2 is typically the longest of the four sleep stages and is characterised by a much deeper sleep as your heart rate and breathing rates continue slowing down and the muscles become more relaxed. Eye movements will also cease at this stage and your body temperature will start to decrease. Apart from some brief moments of higher frequency electrical activity, brain waves also remain slow.
  • Stage 3 /NREM: This stage plays an important role in making you feel refreshed and alert the next day. Heartbeat, breathing and brain wave activity have all reach their lowest levels and the muscles are as relaxed as they can be. This stage will be longer at first and decrease in duration throughout the night.
  • REM: The first REM stage will occur about 90 minutes after you fall asleep. As the name suggests, your eyes will move back and forth rather quickly under your eyelids and your breathing rate, heart rate and blood pressure will begin to increase. During the REM stage of sleep, dreaming will typically occur and your arms and legs will become paralysed – it is thought that this is intended to prevent you from physically acting out your dreams. The duration of each REM sleep cycle increases as the night progresses. This is a very interesting stage of the sleep process as many studies have linked REM sleep to memory consolidation. This is the process of converting recently learned experiences into long-term memories. Also, the duration of the REM stage decreases as you age which causes you to spend more time in the NREM stages.

The four sleep stages repeat cyclically throughout the night until you wake up. For most people, the duration of each cycle will last about 90-120 minutes. NREM sleep constitutes about 75% to 80% of each cycle. You might wake up briefly during the night during one of the stages, but not remember doing so the next day and these episodes are known as “W” stages.

So How Much Sleep Do I Actually Need?

The right amount of sleep depends mainly on your age and ranges from a young baby requiring 12-16 hours, a teenager 8-10 hours and adults around the recommended 7 hours a night.

Getting the right amount of sleep each night is essential for proper cognitive and behavioural functions. Insufficient sleep can lead to problems such as attention lapses, reduced cognition, delayed reactions and mood swings. Rather counter-productively it is thought that people can develop a sort of tolerance to chronic sleep deprivation. Even though the brain and body struggle due to lack of sleep, a sleep deprived person may not be aware of their own deficiencies because less sleep feels normal to them. Additionally, lack of sleep has been linked to a higher risk for certain diseases and medical conditions such as obesity, type 2 diabetes, high blood pressure, heart disease, stroke and poor mental health.

Having read this, you may think you are lacking sufficient sleep and that your bedtime routine could do with a bit of an overhaul! So, here are some simple action points that can help you achieve some long-term positive lifestyle sleep habits:

  • Establish a sensible bedtime and stick to it every night, even, wherever possible, at the weekend
  • Make sure the temperature in your bedroom is comfortable and also keep the light levels low
  • Are you comfortable? Optimise sleep quality by ensuring you have the best mattress, pillows and duvet /sheets for your body type
  • Consider a ban on all ‘screens’ in your bedroom: televisions, computers and tablets, cell phones and any other electronic devices
  • Aim to avoid caffeine, alcohol, tobacco and large meals too close to your bedtime
  • Do your exercise during the day as this can help you wind down in the evening and prepare for sleep

Good Luck & sweet dreams!

January 31, 2024

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