How to Optimise Your Circadian Rhythm (Part II)

Would you like to find a smarter way to go about your day? No, it’s not about trying to better yourself with the latest smartphone app, watch or ring. It’s much simpler than that. What it’s really all about is becoming mindful of your daily rhythms. In this article I am going to show you how to optimise your ‘circadian rhythm’.

What is our Circadian Rhythm?

Well, put it up simply, it’s the ‘thing’ that governs our daily cycles, almost down to the minute and second. These are the things that regulate our physical, mental and behavioural activities on a 24 hour cycle based on certain times of the day (although it is suggested that the actual cycle may be slightly longer than 24 hours). On top of that, our ‘biological clocks‘ govern our circadian rhythms, and are based on certain proteins which interact with cells throughout the body.

On top of all the biological clocks, we have the ‘master clock’ (or ‘internal clock’) which governs all the biological clocks in a living being. In humans, it comprises about 20,000 nerve cells (or neurons) that form a structure that is known as the “suprachiasmatic nucleus”, or SCN.

The SCN is located in the part of the brain called the hypothalamus and is sensitive to bright light through the eyes. Light exposure is stimulating and is known to advance our internal clock (whilst light in the evening delays it). We can also see that the pineal gland is innervated by a synaptic series of nerves from the SCN, which produces melatonin, stimulating the desire to sleep.

When we start to realise how much we are governed by our daily cycles, we begin to notice things. We may notice when we start to wake. We also may notice when we start to fall asleep. Some people are early risers (known as ‘larks’). Others may have a tendency to stay up late (known as ‘owls’). The precise cause of what determines whether someone is a lark or owl may be down to a combination of behavioural and biological circumstances, but broadly speaking humans follow the same cycle of being awake and active during the day, and sleep and resting in the evening.

In the school of Ayurveda, the sister science to Yoga, the times of day are broken down into a number of cycles. It is during these times that govern our sleep wake cycle.

The Morning Cycle (6AM – 10AM) – Elimination, Exercise, Energy

The morning cycle that starts each day is greeted with a sense of heaviness from the previous night time, whereby the element of ‘earth‘ is most present. We can feel this sense of lethargy as we awake, sometimes struggling to get out of bed. Whilst a lie in may be warranted after a long night or week, sleeping through the morning may leave us feeling heavy and groggy. This is because we are sleeping in a cycle that is designed for activity and exercise. Ideally, our wake up time is around the time that the sun is rising.

If we live according to our cycles, often attuned with the rising of the sun, we may notice that at the point of rising, the body becomes finely tuned like a clock. At the point when the night time cycle ends and the new day begins, we may begin the day with the urge to eliminate through a movement through our bowels.

Between the hours of 6AM and 8AM, to counter any lingering feelings of sluggishness or heaviness from the previous night, light exercise is recommended. In yoga of course, we know this as ‘surya namaskar’ or sun salutation. Light exposure is stimulating and the practice of sun salutations honours this. See below myself demonstrating surya namaskar across various parts of London.

credit: Richard Pilnick

Contrary to popular belief, breakfast is not the most important meal of the day (we can thank the Kelloggs brothers for this myth). Although some food may be helpful to provide us with energy to start the day, in Ayurveda the purpose of food in the morning is to lightly stimulate our digestion, preparing us for the main meal during lunch time. Often I find delaying eating until around 10AM helps to bring a more consistent and stable digestion.

The Lunchtime Cycle (10AM – 2PM) – Eating & Sunbathing

During the middle of day, the element of ‘fire‘ is most predominant. The sun is at the peak of its power and it is where our digestive capacity is at its greatest. At this point, we can digest heavier foods for maximum energy and vitality. On a practical level, having a large meal during the middle of the day, reduces the desire for a sugar-fix in the afternoon.

This will also bring the other cycles into balance so that everything is optimised at their naturally designed times.

The sun of course is where we derive the majority of our vitamin D and some exposure to natural light during this time is healthy. Bear in mind that the sun also brings with it the risk of over-exposure, but some exposure during the middle of the day is healthy. We know that strong bones relies upon healthy levels of vitamin D, as well as other areas relating to the immune system and mental health.

The Afternoon Cycle (2PM – 6PM) – Siestas & Energy Slumps

During the afternoon cycle, there is a natural reduction in energy and concentration. It is the predominant time of the element of ‘space‘ and ‘air‘. We may notice that we have trouble concentrating, feel the desire for a nap or otherwise reach for a snack or other short term burst of energy.

The Spanish are of course famous for their naps (known as ‘siestas’) and they may be a short term solution for any feelings of tiredness or low energy. Interestingly enough, whilst a ‘power nap’ may help with feelings of tiredness, napping itself is not recommended for everyone, especially those with a kapha predominance, which may induce feelings of sluggishness and dullness. It is also recommended to nap in a sitting or semi-reclined position.

My own experience of napping suggests they may be useful if I have an existing sleep deficit, but otherwise I try not to include them regularly as they impact my natural sleep cycle. For more information on how to nap, please see here.

The other way to counter feelings of low energy during the afternoon is through healthy, energy-boosting foods and drinks. In the tropics, coconut juice is consumed, sweet lassi in India is enjoyed and herbal tea is sipped throughout Japan and India. This can also help reduce the temptation to over-eat at dinner time, which may affect our quality of sleep.

If exercise is not possible early in the morning, the next best time is late afternoon or early evening, after we have digested our main meal of the day. Exercising too late into the evening stimulates the central nervous system and may interfere with the body’s natural desire to begin winding down.

The Evening Cycle (6PM – 10PM) – Light Food & Unwinding

After 6PM, the qualities of the ‘earth‘ begin to emerge again. It is the time for slowing down. As the sun sets, so does our digestive capabilities or ‘fire’. It is not just our digestion that begins to slow down, but all of our major organs and bodily functions. One of the hallmarks during this period is ‘eating light’. Eating heavy meals at night interferes with the body’s natural rest and restore functions during sleep (as we will see in the next section).

Of course, this is the complete opposite in the western world where often their heaviest meal of the day in the evening is consumed, especially after a long day at work, and perhaps with inefficient nutritional habits during the day. It has also been suggested that weight gain may also be attributed to the time of day that people eat. One study found that mice which ate at irregular times put on almost two and half times the amount of weight than those that ate at regular times whilst consuming the same amount and type of food. So the lesson is not to calorie count, but to be mindful of the time of the day that those calories are consumed.

The Night Cycle (10PM – 2AM) – Peak Wave for Rejuvenation

From an Ayurvedic perspective, the most important time for optimal health is the natural cycle that begins from 10PM to 2AM. This is known as the second ‘fire‘ cycle and is where the body ‘consumes’ any impurities that that have been deposited or arisen during the day. Staying up during this period of time might even result in increased hunger or ‘midnight munchies’.

Interestingly, even this period is associated with the qualities of fire, the core body temperature is known to drop slightly with minimum temperature occurring in the morning which is suggestive of the fact that the body may not be in the optimal state to be consuming food (rather it is cleansing).

However, this period is not designed for digestion – rather, it is designed to ‘digest’ any toxins and foreign substances. We can say that eating at the wrong time of the day may result in weight gain if the body is in a ‘cleansing’ mode yet it also required to digest food. It may also result in a feeling heaviness or sluggishness upon waking. The later we go to bed, the more we miss this cycle with the resulting stress, and fatigue building in the body.

Whilst some who do shift work or suffer from jet lag cannot help their situation (especially those in the line of duty or fly long haul whilst working in the airline industry), unhelpful habits of staying up late to watch tv, consuming social media or playing computer games (thereby becoming exposed to blue light) can affect the quality of our sleep at night.

What’s more, the contribution to health through healthy sleep patterns has been documented through many cultures around the world where centenarians are prevalent.

Whilst observing why the people of the village of Campodimele in Southern Italy experienced significant longevity (more than 30 years longer than the average Italian), one of the observations was that they went to bed soon after dusk and arose at dawn. Of course, diet and other factors may play a part, but regular sleeping habits can only help contribute to healthy ageing and overall health.

The conclusion is that if we really want to improve sleep, aim to go to bed early according to our natural cycle.

Early Morning Cycle (2AM – 6AM) – Deep Sleep, Waste Management & Wake-Up

At this point of the cycle, other than those parts of the body that are dedicated to repair and revitalisation, the body’s physiology is at its lowest level of functioning. This is known as the ‘circadian nadir’. In the Ayurvedic scheme of things, the natural purpose of this period is to complete the internal cleansing process. Dreaming and rapid eye movement is common as well as the completion of the cleansing of the brain, where waste material is ‘washed’ through the cerebrospinal fluid that circulates around the brain, through the spinal cord and the sacrum.

In the context of the brain being strongly associated with our mental faculties, we can see getting a good night’s sleep is so important for mental health as well as optimal performance during the day.

From an elemental perspective, the qualities of ‘air‘ and ‘space‘ are present. We can learn to appreciate this whilst waking after a good night’s sleep, where there is a feeling of lightness and ease.

Modern Science & Circadian Rhythm

For many thousands of years, ancient wisdom has known about these daily cycles and respected them. In today’s modern age we are able to measure our cycles, through the interaction between our ‘need to sleep’ and ‘urge to sleep’, giving rise to our ‘sleep drive‘. In more technical terms, this is the balance between our sleep homeostasis and our circadian rhythm, which is represented in the chart below (source).

From this, we can see that our peak time for alertness is around 10AM and 6PM, with a slight dip during the middle of the afternoon. This corresponds to the times of day during our natural cycle when the body has rejuvenated itself after food and rest with a slight dip during the afternoon, which is dedicated to digestion.

How to Optimise your Circadian Rhythm

Knowing all of this, why aren’t we being smarter with our time? For example, we often supercharge our adrenal our adrenal system with a hit of caffeine first thing in the morning when we are often the most alert as a result of rising cortisol levels. Of course, some people may feel the need to do so if their natural cycle is out of rhythm so they awake feeling tired and sluggish.

We schedule important meetings or interviews during the peak ‘drowsy’ zone (between 2 and 4PM), and often make important decisions when we are the least alert.

We also tend to eat early in the morning or late in the evening when our digestive power is at its weakest giving rise to digestive issues and disturbed sleep.

It doesn’t have to be like this.

Knowing what we know about our natural cycles and circadian rhythm, gives us a ‘competitive’ advantage.

We could rather have strategic cups of coffee or tea when our energy levels of dip. Or we could allocate certain times of the day to certain tasks based on their importance and the required level of brain functioning. Eg when we are the most creative, we may wish to write later in the afternoon.

We may also wish to make important decisions when we feel the most alert. We could create a routine that does not engage in activities that are stimulating or exposed to artificial light late in the evening, helping us to enjoy quality sleep.

Overall, the modern world we live in often conflicts with our natural circadian rhythm. Yet, with some insight and wisdom, we can start to adapt our habits to being in sync with these natural rhythms.

To this extent, if we really want to master living in this world and improve our wellbeing, we need to optimise our circadian rhythm and be subject to the laws of nature. With this knowledge, moving in synchronicity with these natural laws can become the bedrock of our wellbeing and the basis for living a long, healthy & productive life.

Scott Robinson

I’d like to give credit to Mark Bunn and his excellent book, ‘Ancient Wisdom for Modern Health‘ for inspiration.

As originally published on Yogibanker

If I can help improve your wellbeing, please feel free to get in touch.