15 mins read

Sleep Cycles

Abnormalities in sleep quality and duration quickly reduce mental and physical performance while placing significant stress on the body.

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In this article:
  • REM Sleep and NREM Sleep
  • The Circadian Sleep Cycle
  • Light and Melatonin
  • The Eat-Sleep Cycle
  • Sleep Pollution
  • Sleep Disorders and Sleep Deprivation
  • Your Internal Body Clock
  • Delayed Circadian Rhythm
  • Supplementing Sleep
  • Natural Circadian Rhythm
  • Natural Ways to Improve Sleep
  • Circadian Rhythm Reset
  • Fix Your Sleep Schedule

The Sleep Cycle

The average sleep cycle takes around 90 minutes, but some people have shorter cycles of just 70 minutes while others can be as long as 110 minutes. This is why tracking your sleep is an important piece of data to determine the best personal pattern. The sleep cycle fluctuates between two main phases: NREM (or non-REM) and REM. 

REM Sleep and NREM Sleep

There are four stages of sleep (the accepted model used to be five stages but this has been revised to reflect the latest research in sleep brainwave activity) which we cycle through several times each night. 

Rapid Eye Movement (REM) is the most well-known stage. During REM sleep the eyes, while closed, flicker and move rapidly and we often dream. During this stage we consolidate memories, and waking occurs easily.

The other three stages of sleep are known as quiescent sleep:

  • NREM1 (drowsiness, transition to sleep, can feel hypnagogic ‘jerks’ as you ‘fall’ asleep) lasts less than 10 minutes and requires relaxation and stillness.
  • NREM2 (decrease in muscle activity, easily awoken with bursts of brainwaves) lasts 30 to 60 minutes
  • NREM3 (deeper state of sleep, body fully relaxed, temperature drops) lasts 20 to 40 minutes, harder to wake somebody up in this stage

Both NREM 1 and 2 are light sleep, while 3 is much deeper. You pass through all stages to get to REM sleep and if you accidentally awaken while in a deep sleep state you will feel groggy.

The body restores itself (growth hormones, cell repair and cleansing the brain via the glymphatic system) during deep sleep. This means disturbed sleep, or feeling ‘wired’ (caffeine, stress or insomnia) you miss the deeper stages needed to fully rejuvenate the body. 

Missing stages of sleep is like tidying up your house but not cleaning – it might look alright on the surface, but deep down the dirt is piling up and a lot of maintenance is overdue...

The Circadian Sleep Cycle

​​The circadian rhythm regulates physiological processes to ensure biological functions are optimized to take place at specific times. From an evolutionary perspective this adaptation meant animals could hunt or hide at night, and even protect DNA from UV sunlight (by keeping it tightly coiled during the day and replicating cells at night). 

The term circadian comes from the Latin ‘circa diem’ meaning ‘around the day’ and herein lies the problem. Our internal clocks only keep approximate time; they need to be kept in sync with light and more importantly, the demands of our environment. Just like Pavlov’s dogs, if you train your body to eat at midnight and stay awake until 3am on the weekends, it will be hard to convince it to sleep at 10pm during the week. 

As far as your body is concerned there is a best time to do everything, but we rarely take the time to plan it this way!


We experience circadian rhythms shifts as a result of conflicting, or irregular, messages to the body about our energetic and physiological needs. When feeling stressed the biological message is ‘danger’ so it’s not surprising the body won’t relax and fall asleep.

The circadian sleep cycle needs to be encouraged and maintained with a calibrated circadian lifestyle to maximize your physiological efficiency. While spontaneous is fun, imagine trying to plan a trip when busses turn up when they want, with no timetable. Irregularity equates to stress on the body and combined with a lack of sleep it creates a multitude of hormonal dysfunctions. 

Fortunately, this circadian temporal disruption is relatively simple to resolve. When you send the correct signals to the body, at the anticipated times, hormones harmonize into regular rhythms that are much more efficient. You’ll be pleased to know that the outdated model of light mastering our clocks has been replaced with a much more manageable solution, as long as you keep a few things in check.

Light and Melatonin

There's a hormone in the body that plays a crucial role in regulating or disrupting the Circadian Rhythm. As light levels drop in the evening we secrete the hormone melatonin which helps us drift off to sleep. But, it’s a subtle hormone and doesn’t compete with cortisol (stress) or caffeine! 

Hormone levels are also effects by the amount of light our retinas absorb. Increasing levels of light reduce the amount of melatonin that is produced, making us feel more awake than we want to be. Artificial light is one of the main reasons for the changes in our circadian rhythm. The exposure to light could happen at any time of the day, and our brains can’t tell if it is natural or artificial. 

Smartphones, computers, tablets, shiny billboards and even household lights impact melatonin levels negatively. They trick the primitive brain into thinking that we are still in daytime even during the night, keeping us awake. In addition, If you resist the peak in your melatonin window the urge to sleep is missed which could lead to less restorative sleep.

The Eat-Sleep Cycle

Before we electrified and lit up our global environment, the sun provided all illumination. The regular rising and setting of the sun provided visual, and temperature cues, to recalibrate our inner clocks (distributed through virtually all our body tissues with 40% of our proteins being rhythmically expressed under the control of circadian genetic expression). 

Today we no longer see the sunrise or sunset and don’t need to rely on natural sunlight to get work done. Meals, movement and any activity patterns used to be within the patterns created by light, but not any more.Eating, digesting, metabolizing and eliminating waste is a resource intensive task that requires lots of specific biological substances and actions. These functions are controlled subconsciously (we can’t decide to get our stomach ready for digesting food) by regular patterns or specific cues. The smell of food being cooked is a biological signal which makes our mouth’s water (producing amylase to break up the carbs) and gets the stomach pumping out digestive juices. 

Food is a major trigger for the circadian system but we rarely eat at the same times, or consistently, so the body doesn’t know what to expect. Imagine a busy restaurant, fully booked, but nobody turns up on time. Four tables of 10 arrive to eat when you are expecting to be cleaning the kitchen. We can’t ‘tell’ the subconsciously controlled systems that we will be eating in a few hours’ time, but with regulatory and rhythmic gene expressions, the body comes to expect it, and is better prepared for all the action required.  

Sleep Pollution

Disturbance of our light and food patterns is just one of the modern issues messing up our inner ability to tell the time! 

Electromagnetic Smog: There is a growing body of evidence suggesting that exposures to electromagnetic frequencies (mobile phones, cell towers, WI-FI etc) is disrupting our sleep. Daytime EMF exposure (e.g. living near a mast) of just 30 minutes increases the brainwave amplitude during REM sleep, reducing its restorative capacity. Even low frequency electromagnetic fields reduce sleep duration and make it harder to get to sleep.

Background Noise: The main component of environmental noise in modern times is transportation. Noise from vehicles provokes measurable biological changes (akin to the stress response) negatively impacting sleep patterns and quality. Over a prolonged period nocturnal noise is dangerous for your health, it increases the risk of cardiovascular and respiratory diseases and reduces quality of life. Despite its popularity, there is little evidence to suggest that listening to white noise can ameliorate this issue, it could be adding to the problem.

Afternoon Napping: Think of napping as like putting your phone in charge. The more your battery is charged, the less tired you feel. If your battery is significantly charged at the moment you go to bed, it will be more difficult to fall asleep. Research suggests not napping after 2pm and keeping it short for a brief period of restoration under 15 minutes.

Evening Exercise: Intense workouts release epinephrine (adrenaline), a hormone that keeps the mind alert. After intense workouts less than two hours before bed stops the body from cooling down and making it difficult to relax. Conversely, gentle exercise like yoga, stretching, slow walks or breathing exercises have been proven to be beneficial for better sleep.

Stressful information: News, arguments, reading or watching intense topics can also set us in an alert state, making it difficult for our brain to relax and fall asleep.15 minutes of the news (which is fear inducing by design) triggers anxiety and negative mood disturbance which needs to be actively resolved with a relaxation activity to drop cortisol to baseline levels.

Diet: Caffeine is among the most popular stimulants in society. If you don't want to interfere with your circadian rhythm, it is recommended that the gap between your last caffeine ingestion and the moment you go to sleep should be no shorter than 6 hours. Caffeine blocks a sleep-promoting chemical called adenosine, making us feel alert and awake.  Alcohol, fatty meals, spicy foods, and artificial colorings can all keep you awake. Snacking on high-carb, but easily digested, fruit (specifically bananas and cherries) can help you sleep better as they contain tryptophan, a melatonin precursor.

Related:  How To Incorporate Coffee In Your Daily Routine

Sleep Disorders and Sleep Deprivation

The latest research on sleep patterns indicates that sleep deprivation significantly enhances other physiological and mental stressors. The combination of increased sympathetic activity, elevated blood pressure, raised evening cortisol and disturbed insulin response, create a maladapted circadian feedback loop that’s difficult to reset. Emotional balance, mood and cognitive abilities also decline impacting our ability to be our best selves.

Circadian rhythm sleep disorders represent a growing class of sleep disturbance. A lack of temporal synchronization within the body (some parts seem wide awake, while others want to sleep) creates chaos for our homeostasis and leads to an uncomfortable, and unhealthy, mix of insomnia, hypersomnia, reduced energy and afternoon lethargy.

Your Internal Body Clock

Our issues with sleep are a symptom of our lifestyle irregularities (also known as social jet-lag) and disconnection from the natural calibrations crucial for our internal body clock. Living out of alignment with our internal clock is specifically associated with increased risk of metabolic diseases. 

The discrepancy between our internal and social clocks impairs our ability to manage energy and disrupts metabolic hormone efficiency. The biological and social misalignment places strain on the body and reduces predicative capacity for key biological processes. Ideally activities like digestion and detoxification occur on a regular schedule but are delayed when our internal clock is out of sync.

Bright artificial lights, traffic noise pollution, information overload, stimulating substances, and stress are all contributing to the circadian chaos that many people are experiencing. Without the correct recalibration points (light, food and movement) our internal body clocks start operating ‘independently’ from each other. This is like the players on a football team turning up to play a match at different times of the day.

Delayed Circadian Rhythm

Difficulty falling asleep, staying asleep, awakening in the middle of the night and not being able to get back to sleep has become dangerously common across the globe. In the US alone 50 to 70 million adults have some kind of sleeping disorder, with almost 40% reporting falling asleep unintentionally during the day at least once per month.

Drowsy driving is responsible for nearly 2,000 deaths and over 40,000 injuries in the US per year. Nearly 40% of adults don’t get enough sleep (less than 7 hours per day) and persistent insomnia increases your risk of premature death.

“Insomnia was associated with increased risk for all-cause and cardiopulmonary mortality and was associated with a steeper increase in inflammation.”  - Dr. Sairam Parthasarathy, University of Arizona College of Medicine

But, even short periods of distributed sleep rhythm increase your risk of death, and some people seem more able to cope than others:

“Both short and long sleep duration is associated with an increased risk of all‐cause mortality and cardiovascular events.” - Journal of the American Heart Association.

Conversely improving your circadian rhythm, and getting more sleep, improves concentration and reduces the symptoms of Attention Deficit Hyperactivity Disorder while easing anxiety.

At least four different circadian rhythm sleep disorders (CRSDs) have been identified, but many people have mild symptoms of all of them depending on the degree of disharmony:

  • Advanced Sleep Phase Disorder (ASPD)
  • Delayed Sleep Phase Disorder (DSPD)
  • Free-Running Disorder (FRD)
  • Irregular Sleep-Wake Rhythm ISWR)

By monitoring body temperature and melatonin secretion the circadian phase shifts can be clearly seen (in a laboratory). Actively tracking your own sleep, temperature and energy levels can help get you spot the irregularities and recalibrate your internal clock.

The treatments prescribed for circadian rhythm disorders include:

  • Prescribed sleep with a strict schedule
  • Circadian phase shifting to reset the clock
  • Symptom management with hypnotics and stimulants.

While most people don’t have a clinical ‘disorder’ almost everybody would benefit from getting better sleep. Understanding the circadian sleep cycle is the first step in resetting the system, so you can get some better sleep.

Supplementing Sleep

If you’re not getting sufficient sleep you can consider supplementing yourself, with extra sleep or substances to help you get to sleep easier.

Sleep Banking: It is possible to roll-over sleep to the next day, or even get it in advance. If you know you will be lacking sleep get extra when possible with daytime naps or spending longer in bed in the morning.

Melatonin:  Available over the counter in pills or sleep gummies, melatonin is becoming increasingly relied upon as a ‘nutritional’ and ‘natural’ cure for sleep problems. Because the substance is classed as a nutrient, the regulatory structure is different to a drug, but in reality this is how it works. If you take melatonin occasionally, to resolve short term bouts of insomnia, it can help. But in the long-run it will reduce your ability to make your own melatonin and manage your own sleep schedule. Despite the marketing hype, evidence to support its long-term effectiveness and safe use is weak at best.

Hypnotics: Sleeping pills are classed as ‘sedative hypnotics’ that will help you get to sleep and stay asleep. Benzodiazepines (like valium) are anti-anxiety and barbiturates are depressants (slow the body). Natural alternatives (like lavender) are also hypnotic and can be very effective. But all hypnotics address symptoms not the core issue: we have lost our biological cues for regularity and sleep rhythm.

Natural Circadian Rhythm

If you moved to another country you would adjust your clock to local time – most cell phones do this automatically. We all need to ‘recalibrate’ our clocks to local, natural, time. This means embracing the natural patterns of light, getting regular with routines and embracing the necessity of sleep.

Natural Ways to Improve Sleep

If you want to create a lasting change in your sleep patterns and habits then you need to put some effort in and track your results. We are all unique and what works wonders for you may not be the right thing for others.

  • Routine: Set a regular time for getting up, going to bed, meals and exercise.
  • Environment: Make your bedroom ideal for sleeping (cool, calm, quiet, dark).
  • Light: See the sun rise and set, or create the same effect by (limit light at night, use bright light in the morning).
  • Electronics: Avoiding using devices late into the night (they give off light) or filter out the light and if possible turn your wifi router off.
  • Vitamin D: A lack of this vital vitamin reduces sleep quality, but all you need is 20 minutes in the sun to catalyze Vitamin D to its active form just beneath the skin’s surface.
  • Relax: Calm yourself down with active relaxation strategies, like meditation. Just 10 minutes reduces anxiety and helps you feel calmer and ready to sleep, it also boosts melatonin levels.
  • Gratitude: Listing your appreciations as the last thing to do before closing your eyes helps you feel safe and positive, making it easier to fall asleep. 

Circadian Rhythm Reset

Increasing your harmony with nature doesn’t mean you need to go out and hunt for dinner. But a weekend camping could be just what you need. 

Researchers at the University of Colorado ran a study measuring the circadian rhythms of people after sending some of them away for a week long camping trip, while others stayed at home. The study aimed to demonstrate how internal clocks change without the use of electronics and receiving only natural light. 

Five people were equipped with devices that measured their waking and sleeping hours and light exposure. Levels of melatonin in all participants were measured before and after the study to see how their hormones were affected.

Results showed that of the volunteers that stayed at home, operating their normal schedules, their internal clocks were delayed by more than two hours. In contrast to the ones that went on the camping trip, shifted back by two hours. Also there was a significant contrast in melatonin levels, rising in the fortunate ones who went on a camping trip and decreasing in the stay at home group.

A second experiment involving just one weekend of camping, two nights, showed remarkable results with a similar shift in sleep pattern and melatonin. Other studies have seen similar results and it would appear the combination affect (natural light, fresh air, exercise and darkness) contribute to system reset.

Camping appears to be an exceptionally effective way to reset your body clocks and get them all telling the same time!

Fix Your Sleep Schedule

If you want to restore your body more effectively at night and have more energy during the day then you need to sleep and operate efficiently. Your body can’t be efficient when your circadian rhythms sound like free-form jazz, it needs a regular beat and a coordinated melody.

By fixing your sleep schedule and aligning it with natural patterns of light and food, you can reset a lot of the circadian problems we are experiencing.  By actively tracking your sleep and daytime activity data it’s possible to reset your sleep, refresh your energy and rejuvenate your lifestyle to optimize your circadian rhythms.

Sign up now for your personalized circadian rhythm report. How much more could you get out of life if your body was better organized?


15 mins read
Sleep Cycles

Abnormalities in sleep quality and duration quickly reduce mental and physical performance while placing significant stress on the body.

In this article:
  • REM Sleep and NREM Sleep
  • The Circadian Sleep Cycle
  • Light and Melatonin
  • The Eat-Sleep Cycle
  • Sleep Pollution
  • Sleep Disorders and Sleep Deprivation
  • Your Internal Body Clock
  • Delayed Circadian Rhythm
  • Supplementing Sleep
  • Natural Circadian Rhythm
  • Natural Ways to Improve Sleep
  • Circadian Rhythm Reset
  • Fix Your Sleep Schedule