Article 1: Understanding Sleep

Introduction: Sleep Matters

Somewhere in our recent past as a species, we seem to have forgotten about the importance of one of the few things that literally keeps us alive. I am, of course, referring to the most precious of all human habits: sleep. Without it, you might expect reduced cognitive capacity and brain fog, emotional instability, a failure to recover from physical exertion, a lack of energy and even weight gain. Any of those sound familiar? Chances are that at least one of them resonates on some level. The good news is that, with what you learn in this article, there is often a super simple strategy that you can implement to help fix it.

This comprehensive guide aims to offer the knowledge and actionable tools needed to truly optimise your sleep, with tips to enhance both its quantity and its quality. Consider it a concise deep-dive on all things sleep improvement, with easy-to-implement tips on everything from sleep habits to sleep hygiene and beyond. If you’re tired of being tired then this is the article for you. Read on.

Understanding Sleep

It’s time to stop thinking about sleep as this simplistically linear process, only good for ‘getting our head down’ and grabbing some ‘shut-eye’. I’d suggest that it is this very mentality and ignorance that is causing so many of the sleep-related difficulties, conscious or not, so pervasive in the relentlessly fast-paced world we live in today. Sleep deserves some respect. It is incredibly complex, involving several stages that all play an equally important role in maintaining our health and well-being. The following will unpick the 5 stages and offer some insight into the role of each, with reference to the sleep cycle as a whole.

Sleep Stages

Stage: Wake/Alert (W)

EEG recording: Beta waves (some alpha waves during relaxed wakefulness in quiet environments) with the highest frequency and lowest amplitude.

Often referred to as stage W, the wake stage of sleep is a state of relative alertness. Characterised by the eyes being open and constant interaction with the world around us. It is not until we close our eyes and become drowsy that we transition from beta-wave activity to alpha-wave and begin to fall into the other sleep stages.

Stage 1: Light Sleep (N1)

EEG recording: Theta waves with a low voltage.

This stage will only last around 1 to 5 minutes (5% of total sleep time). Characterised by the presence of muscle tone and the emergence of regular breaths, the purpose is to prepare the body for deeper sleep.

Stage 2: Deeper Sleep (N2)

EEG recording: sleep spindles and K complexes

Heart rate and body temperature drop as sleep spindles (powerful bursts or neural activity) and K complexes (long delta waves) begin. This stage will last around 25 minutes in cycle 1 and will lengthen through the night (45% of total sleep time), with its main purpose linked to memory consolidation.

Stage 3: Deepest Non-REM Sleep (N3)

EEG recording: delta waves with the lowest frequency and highest amplitude.

This stage is considered the deepest and most restorative stage of sleep, with tissue reparation and strengthening of the immune system taking place. This stage is also home to sleepwalking and night terrors and is the most difficult stage to wake from. Anyone waking during this phase of sleep will experience cognitive fogginess and fail to fully capitalise on its essential benefits for physical repair, brain detoxification and further consolidation of memories. This stage will typically last for 20 – 40 minutes per cycle (25% of total sleep time)

Stage: REM (Rapid Eye Movement)

EEG recording: beta waves (similar to those during waking hours)

Contrary to popular belief, this stage is not considered a particularly restful sleep stage. You would be correct in assuming that it is associated with dreaming but this does not necessarily translate to recovery. With the exception of the eyes and diaphragmatic muscles, the skeletal muscles are motionless as the breathing rate becomes more irregular and erratic. The onset of this stage will start around 90 minutes from the time we fall asleep, with the first cycle typically lasting around 10 minutes and the final cycle lasting up to an hour. This stage is vital for regulating our emotions, learning, creativity, problem-solving and processing experiences. It is a powerhouse for our cognitive functions.

The Sleep Cycle

A complete sleep cycle will last around 90 to 110 minutes and should include all the stages outlined above. An adult can expect to experience between 4 and 6 of these cycles every night, with early sleep cycles containing more deep, non-REM sleep and latter stages containing longer REM periods. Getting a solid balance at each stage in a cycle is essential for both physical and mental health, as each stage will offer different benefits for immunity, recovery and emotional well-being.

By understanding and appreciating the significance of the sleep cycle, we have a foundation of knowledge to structure our sleeping habits around. This enables the optimisation of our sleep within our own unique and nuanced set of circumstances. It will act as the key point of difference between improving your overall health with sleep and not.

Sleep Quantity

Ensuring Sufficient Rest to Optimise Health

We are often deceived when it comes to the amount of time we think we sleep. You see, time spent in bed does not equal time spent asleep. In this way, it is easy to mistake 8 hours in bed for 8 hours of sleep, when in reality we may get closer to 7 or even 6 hours. In the absence of a sleep tracker, it can be difficult to pinpoint the exact amount of time we spend sleeping each night but by developing our understanding of sleep duration we can get closer to the optimal ranges.

The recommended sleep durations will vary depending on the source they are derived from. With a lack of concrete data from the UK populous, I’ve adopted the National Sleep Foundation’s propositions from the US:

- Newborns (0 – 3 months) = 14 – 17 hours per day

- Infants (4 – 11 months) = 12 – 15 hours per day

- Toddlers (1 – 2 years) = 11 – 14 hours per day

- Preschoolers (3 – 5 years) = 10 – 13 hours per day

- School-age children (6-13 years): 9 – 11 hours per day

- Teenagers (14 – 17 years) = 8 – 10 hours per day

- Young Adults (18 – 25 years) = 7 – 9 hours per day

- Adults (26 – 64 years) = 7 – 9 hours per day

- Older Adults (65+ years) = 7 – 8 hours per day

You may be surprised by some of the guidelines displayed in the list above. However, repeated failure to adhere to these recommendations can have all kinds of adverse effects on the body in both the short- and long-term.

Sleep Deprivation

The acute effects of sleep deprivation are shockingly quite stark. Some may seem obvious but it is perhaps the underlying impact of these effects that is most concerning.

- Physical Symptoms: fatigue and lethargy, frequent yawning, poor coordination and headaches.

- Cognitive Impairment: low motivation, reduced responsiveness, decreased awareness, lowered levels of concentration and productivity.

- Emotional Instability: feelings of irritability, low mood, depression, anxiety, stress and paranoia; all fluctuating in intensity with drastic mood swings.

The short-term effects of insufficient sleep quantity are a daunting prospect for us and indeed those around us! However, it is the chronic build-up of these effects that proves to be truly deleterious for both our mental and physical health.

- Chronic Health Complications: hypertension, dyslipidaemia, cardiovascular disease, metabolic syndrome, type II diabetes and weight-related issues. Evidence even points to an increased risk of cancer and even mortality.

- Mental Health Issues: an increased risk of developing clinical anxiety, depression and other mood-related disorders.

- Immune System Hinderances: a reduced ability for the body to prevent, fight and recover from illnesses, injuries or infections.

- Cognitive Function Depreciation: memory impairments, increased risk of dementia and slower processing of thoughts.

It’s not uncommon to fall into unfavourable sleeping habits, with statistics indicating that 1 in 3 adults will fail to achieve adequate sleep on a daily basis. I hope the effects outlined in this section make you think twice about how long you choose to spend in bed and ultimately how much time you sleep for each night.

Sleep Quality

Enhancing Rest to Optimise Health

Maintaining high-quality sleep is just as important as how long we spend asleep. For the restorative effects that sleep should offer and to wake up each and every morning feeling refreshed, it is necessary to appreciate the key factors that can affect the quality of our sleep.

Sleep Onset

- Otherwise recognised as the time it takes to fall asleep, the onset of sleep is optimal within 30 minutes of shutting your eyes.

Sleep Efficiency

- The ratio of time spent asleep versus the time spent sitting or lying in bed.

Sleep Arousals

- Essentially, it’s just the number of times you wake up during the night. Anything less than 5 awakenings is considered ideal.

Sleep Stages

- Those aforementioned sleep stages are integral to the quality of our sleep. Adequate time attributed to each stage with a good balance is key.