All forms of life have adapted to the circadian changes in the environment specific to the seasonal and daily cycles of our planets rotation and their location on it. Physiological cycles of all living organisms match geophysical conditions. Our brain and complex body systems as well as our intestinal microbiome are no exception, and they in turn condition or impact our physical and mental health. Knowing the key factors to align your circadian rhythm, lifestyle and environmental conditions will enable you to better optimise health, longevity and resilience to chronic illness.

What is our Circadian Clock?

The master controller of our molecular and systemic cycles for optimal health is a small region in the brain called the superchiasmatic nucleus. The various systems that function and influence our circadian rhythms of our digestion, immune system, mitochondrial functioning and microbiome include what can be called ‘peripheral clocks’ to the master controller. Together, master controller and peripheral clocks are important conductors in orchestration and synchronisation of our overall functioning and ongoing health of mind and body.

Outside stimuli like day or night, activity or sleep, feeding and fasting times and temperature are collectively called zeitbergers. Conflict between zeitbergers and our circadian rhythms is linked to metabolic disorders like insulin resistance and pre-diabetes, as well as disruption to leptin (our hunger hormone) and cortisol (our stress hormone) levels.

Many other important functions like the 24 hour cycles of mitochondrial metabolism (eg, sugar versus fat burning) and cyclic gut bacterial sensitivity to melatonin (our sleep hormone) are part of the systemic cycles coordinated by our circadian clock composed of the master controller, peripheral clocks and conditioned by zeitbergers.

The Importance of Regular Sleep Patterns

Chronic disruption of our circadian rhythms is linked to diabetes, obesity, cardiovascular disease and certain cancers. Sleep deprivation as one disrupter, is associated with these conditions as well as deterioration of cognitive and brain functions, lower performance levels, heart disease, stroke, hypertension, depression, immune dysfunction and diabetes mellitus [1].

These conditions are notably associated with aberrant compositions of intestinal microbiome, called dysbiosis. The fact related health conditions can be transferred in mice through dysbiotic microbial transfer and the conditions can be improved with functional microbial transfer or antibiotic treatment supports that microbiota, metabolic diseases and misalignment between the body clock and geophysical time are linked [2].

Inflammation is linked with many chronic illnesses such as diabetes, arthritis, cardiovascular disease, inflammatory bowel disorders, auto immune disorders and various brain disorders like alzheimers and schizophrenia. There is also a link between sleep and inflammation related to microbiome, cytokines in the blood, and inflammasomes. Inflammasomes are protein complexes that form in cells and produce pro-inflammatory cytokines in response to certain changes. They are also a key regulating mechanism for sleep [3].

The Importance our Daily and Microbial Cycles Being Co-ordinated

Light, temperature, availability and type of nutrition are 4 key factors for healthy synchronised physiological and microbial cycles on a daily, monthly and seasonal basis.

The importance and roles of microbiome (the overall communities of microorganisms inside us) have been covered two recent posts. The circadian cycles of our microbiome are part of our microbial system stability. Coordinating these with our circadian cycle is a major factor for metabolic health.

Microorganisms in our bodies are responsible for digestion, conversion of digested material to energy, regulating metabolism including weight gain or loss and determining our response or sensitivities to foods, drugs, and pathogens. Disruptions to their functioning is a major factor for inflammation (associated with practically every chronic illness and condition), systemic and immunity issues.

Life and death cycles of our microbiota follow daily cycles and rhythms according to rest or activity patterns which include energy harvest for our body and brain, DNA cell repair, cell growth and detoxification. Regular and optimal timing of food intake and available nutrients is an important influence on these cycles.

Research shows our microbial cycles are conditioned by our behaviour and molecular rhythmicity and the coordination between these two levels. This new understanding highlights the importance of stability and optimal functioning of the intestinal ecosystem through activity, sleep and eating cycles.

How Do We Optimise Physiological and Microbial Circadian Rhythms?

• Light and Behaviour are key factors for our master controller – exposure to sunlight upon waking and activity as well as low exposure to blue light (LED or bright lights) and rest at night help the master controller drive regular circadian rhythms in sync with peripheral factors. Electric lighting and travel across time zones are modern challenges to the circadian clock mechanisms including light-dark conditions during jet lag or shift work.
• Feeding times are a central driver for peripheral body clocks which show some interdependence by influencing shifts in microbial cycles away from the overall circadian rhythm of the master controller. Tests indicate it is not the high-caloric, high-fat content of diet responsible for metabolic disease as much as the mistiming of nutrient availability in relation to circadian metabolic activity. So while quality and type of food does impact quantity and diversity of our gut microbes, consider timing as a key lifestyle factor.

Beneficial ways to maintain circadian clock alignment are:

1. Feeding times: limited to 9-12 hour daytime windows is ideal and helps regulate body weight and metabolic health [4] as well as inflammation, it also helps overcoming any challenges related to disrupted sleep patterns, travel across time zones or insomnia. Allow two or more hours between the evening meal and sleep.
2. Regular times for sleep and rising has the same benefits as limited feeding times.
3. Exposure to sunlight upon rising (20 mins or more outside is ideal) activates daytime cycles. Dimming lights and leaving blue spectrum lighting off in the evenings after eating and at least two hours before sleep helps activate the night time cycles.
4. As an added tip, combining sunlight exposure in the morning and night time darkness exposure with a corresponding 20-30 minute period of morning and evening ‘earthing’ (barefoot on earth, sand, or gravel) can assist with sleep issues, inflammation and can provide good mental relaxation at the start and end to each day.

Articles on this website share effective and powerful approaches to maintaining mental and physical health and approaches to inner peace and awareness based on my personal and professional experience, functional medicine approaches and the latest research from journals. If this article was interesting or useful to you, please make a comment below.

References:

1. P.B. Jarreau, Why Your Gut Microbes Love Intermittent Fasting, Medium Corp., https://medium.com/lifeomic/why-your-gut-microbes-love-intermittent-fasting- 5716948281a3
2. A day in the Life of the meta-organism: diurnal rhythms of the intestinal microbiome and its host. C.A. Thaiss, D. Zeevi, et al., Gut Microbes, Vol.6, 2015. https://doi.org/10.1080/19490976.2015.1016690
3. M.R. Zielinski M.D., Sleep and Inflammation – Intimate Partners in Health and Functioning, Thrive Global. 2017, May 16. https://medium.com/thrive-global/the-fascinating-link-between-inflammation-and-sleep-9d57c2eca013
4. A. Zarrrinpar, A. Chaix, et al., Diet and Feeding Pattern Affect the Diurnal Dynamics of the Gut Microbiome. Cell Press, Vol.20. 2014. DOI https://doi.org/10.1016/j.cmet.2014.11.008

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