Optimizing your biological rhythms enhances physical and mental performance.
Our inner clocks are out of sync, and our health is suffering. The misalignment of our illuminated lifestyle with plus hectic work and social schedules is contributing to chronic disease. Our temporal deregulation has become so severe that Circadian Rhythm Disruption resembles a Traumatic Brain Injury. [source]
“Professional football players playing close to the circadian peak in performance demonstrate a significant athletic advantage”
Creating circadian rhythms synchronicity provides a significant performance advantage and improves virtually every aspect of your physiology.
Life on Earth evolved by adapting to daily fluctuations in light - day and night. Bacteria protected their DNA from UV-induced mutations by replicating genes at night. Organisms evolved to thrive in their niche environment, using resources physically and temporally like adopting the best times to perform specific actions, like hunting.
Environmentally triggered temporal adaptations (biochemical, physiological, and behavioral) must align with the environment. In mammals, including humans, this internal time-management system is called the Circadian Rhythm. Like any good timepiece, it needs to be robust, self-sustaining, and relevant. What use is a clock if it tells the wrong time?
Unfortunately, our modern environment lacks temporal coherence. We have variable meal times, light at night, and flexible sleep patterns. Biological clocks require near-constant conditions to effectively track and predict time and energy requirements. But that is not what we give them!
The selective advantage of time-sensitive biology has propagated through our genetic lineage several times.[source] The ability to anticipate biological fluctuations by entraining internal processes to external conditions has provided an ‘edge’ for over 2.5 billion years.[source]
Internal and external coherence is maintained by biological clocks that respond to the environment. zeitgebers (German for ‘time givers) are external cues (environmental and social) that influence internal biology. Light is the primary zeitgeber, but other influences (such as temperature, routine, food, and stress) also impact our ability to be ‘on time.
In just a few decades, humans have taken complete control of our environment; heat, light, and food supply. This has undermined predictable natural rhythms. Global business, international travel, and shift work have pushed people out of their ‘natural’ time-zone.
Reduction in natural light exposure, excessive use of caffeine, sedentary lifestyles, variable food times, and late-night binges have pushed us out of sync with our natural biology. Eroding our natural rhythms and zeitgebers creates a host of metabolic problems, immune dysfunction, neurobehavioral abnormalities, and cancers.[source, source, source]
Aging is accelerated when Circadian Rhythms are misaligned. Alzheimer’s, schizophrenia, and bipolar depression are associated with circadian disruption.[source]
Within the hypothalamus (the brain region controlling homeostasis) lives the suprachiasmatic nucleus (SCN); it contains 20,000 neurons that create a ‘master’ clock. [source] The SCN receives information about external light conditions directly from the retina (back of the eye) and is exceptionally sensitive.
Exposure to light either advances or delays the signal sent out by the SCN. This, in turn, synchronizes genetic, biochemical, and behavioral rhythms with the natural dark-light cycle. The neurons ‘tick’ at a regular pace, and resonate with neighboring neurons, to create a robust self-sustaining rhythm for both gene expression and brain activity. [source]
Neurons from the SCN project into hypothalamic nuclei that regulate sleep, wakefulness, temperature, and appetite.[source] The SCN, in turn, imposes a regular schedule of activity and drives a rhythmic release of neurotransmitters, hormones, and glucocorticoids (like cortisol).
The impact of disruption is multifaceted. Symptoms appear in various systems which, typically escalate until resolved or disease manifests:
Circadian-controlled biological systems are critical; minor disturbances (reducing temporal logistical efficiency – like a postal strike) create major problems.
Do you have any of these early signs of Circadian Rhythm Disruption?
Note: The above could also be present even without Circadian Rhythm disorder or be signs of an entirely different underlying condition.
A complex system of genes and proteins interact in a time-sensitive manner through interlocked transcriptional-translational feedback loops (TTFLs). The SCN, together with the peripheral clock genes, creates temporal harmony; coordinating biology and behavior with the external environment. Micro-DNA analysis revealed global disruption of genetic pathways in the liver (controlling glucose and lipid metabolism). Circadian disruption can manifest at a molecular-genetic level in a relatively short time.
Studies that mutate or delete clock-components “unanimously support a view that normal clock function is important to well‐being”
Cells and tissues have their own time-keeping ability. Until recently, it was thought that the SCN provided timing information to the body. Now we know the relationship is bi-directional. The SCN works with the peripheral clocks to harmonize the whole operation.
The SCN controls the master clock (that ‘tiks’ even without a dark-light cycle) and is synchronized with peripheral clocks - creating a Federation of timekeepers that collectively agree on the ‘right’ time (to perform a function). [source] The Federated model suggests the SCN exerts its ‘standard’ rhythm only when zeitgebers are missing or conflicting. [source] This means you can provide specific zeitgebers to resynchronize and retrain the entire system!
Local tissue clocks control the expression of specific genes. Regulatory pathways crucial to survival (like glucose management) are under tight time control to ensure coordination with other organs (liver, muscle, and adipose tissue) [source, source, source]
The basic SCN rhythm is reinforced with hormonal patterns (notably melatonin and cortisol) that contribute, compliment and consolidate the cycles. The secreted factors act to propagate, entrain and enhance the amplitude of the SCN signal. This means if either your cortisol or melatonin levels are disrupted (stress and insomnia anyone?) any irregularities in the cycle are exaggerated, and the problem gets worse. Until you interrupt the cycle.
Daylight drives alertness, with cortisol and other hormones that keep us awake. As light levels drop, the reduction in SCN stimulation initiates melatonin production to make us sleep. This aligns sleep and wakefulness to day and night, creating restorative rest and optimizing daylight hours for activity.
Wakefulness is the main cycle controlled by the SCN, but many other circadian oscillations are coming to light. Blood glucose management, metabolism, inflammation, the immune system, mood, memory, DNA repair, and neuroregeneration are all subject to daily rhythms. [source, source]
The criticality of clock-controlled processes reveals how and why becoming ‘out of phase’ can be so detrimental to health. These are the key biological processes under rhythmic control:
There is a ‘chicken and egg’ conflict regarding chronotypes. Are we genetically pre-destined to be early or late risers? Do our actions influence epigenetic adaptations, steering our time preferences? Or, are some people better able to pick up the subtle environmental cues or more able to stay in tune without predictable signals?
The health benefits associated with chronotype suggest we should be trying to steer our temporal destiny and seek zeitgebers that realign us with ‘natural’ time. The mental and physical performance gains from an efficient, entrained, and naturally resonant rhythm can provide an energetic edge for everyone from athletes to entrepreneurs.
Differences in day and night activity and alertness allow us to label chronotypes.
It’s possible to assess chronotype using self-reporting questionnaires (including the floating Circadian Rhythm Test button on this page). But, accuracy depends on recall and estimating how you would respond to different mental and physical tasks.
Alternatively, studies using Ambulatory Circadian Monitoring (ACM) sensors gather moment-to-moment data (environmental light and temperature exposure, wrist temperature, body position, and activity) under free-living conditions. This vast dataset can help classify individuals. Typically some 60% sit in the middle with no preference, approximately 20% are early-types & 20% are late-types.
Circadian-controlled genes are involved in all of your critical biological functions. This means even minor gains in efficiency have an impact. When the whole system resonates in harmony with your schedule, you can expect the following:
Improving your Circadian Rhythm makes your body much more efficient. An efficient body has ‘spare’ energy to think, repair the body, remove toxins and operate at peak performance.
Establishing optimized circadian rhythms, entrained to your routine, allows you to schedule critical tasks for peak performance points in your day.
It is possible to re-establish an efficient and healthy circadian resonance with the natural environment (or optimize your lifestyle e.g. shift-work). By modifying personal zeitgebers you can entrain a more efficient oscillation of gene expression.
Through careful analysis of shifts in your energy, glucose, sleep, and subjective well-being, it's possible to identify and optimize your genetic expression.
Zeitgebers put you back in control of your genes - you get to shift their operation to suit your lifestyle! All you need is the right data to determine what optimizes YOUR rhythm.
Altered sleep-wake patterns displace sleep, and sleep is the next most important zeitgeber. Sleep is fundamental to your rhythm and a biological necessity that we often skimp. Regular sleep patterns (with less than one-hour variation) entrain quicker payoff. The sleep-inducing hormone melatonin is made exclusively in the dark!
Instead of overriding tiredness with coffee (which messes with alertness), consider a nap instead. Napping (ideally early afternoon) improves memory, learning, creativity, alertness, mood and reduces stress:
Athletes napping for 20 to 90 minutes between 1pm and 4pm improved: performance, perception, and psychological state without compromising night-time sleep quality.[source]
Avoid caffeine-containing substances and stimulants after midday (coffee, green tea, chocolate and even chili). Consider supplementation with nutritional metals:
The SCN sits in the home of homeostasis, the hypothalamus. Homeostatic thermoregulation (body temperature) varies throughout the day. Piggy-backing this temporal-temperature signature can reset and retrain your rhythms. Anticipatory regulation expects a rhythm oscillation between 36.5 and 38.5 °C. Cells with peripheral clocks respond to temperature change, helping synchronize with the SCN. Thermo-detecting proteins seem to be able to reset molecular-peripheral clocks.
The next critical factor is food intake (type, time, and portion size) with glucose and insulin-regulating peripheral clocks (e.g. liver and kidneys). Peripheral circadian clocks entrain to food and de-couple from light and the SCN. For most of the body, this means the signals from food are more important than the SCN. Using the Federated model, it becomes obvious that the body needs to try and predict significant energy drains (such as digestion). If you often eat at 3 am, this is the key signal you will entrain and resonate with. Food availability drives both behavior and metabolic functions (e.g. seeking food, insulin secretion)
So, avoid late-night snacking unless you want to entrain your stomach to a different time zone!
Secretion of the wakefulness hormone cortisol is what gets us going in the morning. So, it should be no surprise that stress (cortisol excess) interferes with circadian regulation. Several clock genes have promoter or enhancer regions that respond to stress hormones. Clock gene activation provides the molecular basis for how stress impacts circadian rhythms. Stress reduces night-time pineal melatonin production and increases daytime production. Inflammation also signals physiological stress which impacts the production of other hormones.
The ‘active’ phase of the day should contain exercise, social interaction, and feeding. When these activities are missing, the day is not ‘complete’. Daily exercise reduces stress, tires you out, and uses up stimulating hormones. Night-time exercise can dramatically shift the phase timing of melatonin production – it confuses the body so much that the next day's circadian dusk is delayed by up to 12 hours. Activity creates internal coherence between peripheral clocks and the SCN. During the day it is ‘movement’ that directs different physical demands; wake up, get up, go hunt, rest, socialize, fight, mate, sleep, etc. Chrono-biologically there are benefits to exercising at different times of day:
Whatever your rhythm, it will be enhanced by routine (gaining more efficiency). Try and create consistency (in timing) across your work and personal life. Plan to compensate sleep for timezone ‘changes’ (international travel or personal behaviors). Awareness of your rhythm plus performance data will help you optimize your temporal alignment. Personal experimentation will highlight the best times of day for you, depending on your needs.
Just 10-days of circadian synchronicity increases insulin sensitivity and decreases blood glucose, cortisol & blood pressure!
If you had a watch that consistently runs late would you call it an L-type watch? What if the watch started getting dim, had poor battery life, and was getting slower by the day; would you describe this as a ‘feature’ or ‘type’ of watch? No. You would say the watch had a problem!
Science has a tendency to label and study states of maladaptation, not optimized adaptation! Insulin resistance is maladaptation to the food being eaten and toxins inflaming the pancreas. Burnout is maladaptation to levels of stress and the inability to reduce cortisol levels. Late-type chronotypes are maladapted to living a healthy life in our modern environment. But, by resetting the timing, using the language of zeitgebers we can rewrite the schedule!
The critical component of circadian rhythms is the ‘match’ or resonance with the environment, not simply adhering to a specific 24-hour schedule. The ‘free-running period ‘ is what happens to the clocks when they are not working together.
A limited number of animal studies have tracked the benefits of establishing resonant alignment with physiological and behavioral clocks. Human studies are starting now. With me and you.
The performance potential from adding just a little more energy and efficiency is immense. The personal gains in mood and stress reduction make it an experiment worth putting effort into.
Micro-DNA analysis and qualitative assays have pinpointed an ‘ideal time, for an average human, in ideal conditions. This doesn’t often exist, but it is a starting point when considering a schedule. Are you optimizing your day in alignment with your body?
We can’t easily change many things in our modern lives, let alone the time of sunrise and sunset. But, we can pay attention to the signals we give the body and, in turn, get better at meeting our own needs. Your SCN works in unison with organs, cells, and DNA to create a schedule that works. By increasing body awareness, you can train that schedule to align with your life and make it more efficient.
For a more accurate, daily system to track your circadian rhythms, you can use Basis. Basis uses sleep and activity data from your wearables to continuously interpret your circadian rhythm and guide you on how to improve your lifestyle habits to get you more in sync with your circadian rhythm and enhance your health.
Optimizing your biological rhythms enhances physical and mental performance.
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