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Circadian Rhythms: Bulletproof Your Biology

Scrap the fads and realign your body clocks

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Have you ever changed your diet in an effort to overcome nagging health symptoms, but fail to see any progress? As a Nutrition Coach I know this plight all too well: People tend to treat dietary tweaks as a panacea, leaving other important actions ignored and results untapped.

As humans we have developed the complacent notion that because we’re at the top of the food chain, we’re also somehow above nature and biology. Narrator’s voice: But we are not. If your internal human biology is out of sync with your natural environment, health problems become an inevitability no matter what food you put in your mouth.

If you already feel great then this article isn’t for you, but for those struggling within their body here’s the reality: Food is but one input to the human body. If you suffer from symptoms such as anxiety, gut issues, immunity & skin problems, have trouble sleeping or an inability to lose weight, then the problem runs much deeper than nutrition-alone. To get to the bottom of things you’ve got to look at the whole picture; not just food, but the totality of how your organism is living within its environment.

This brings us to today’s topic: Circadian Rhythms, how they impact health, and how you can realign your daily patterns to leave your symptoms in the past.

What are Circadian Rhythms?

As explained in our previous blog on Intermittent Fasting:

“Circadian rhythms are 24-hour cycles that dictate the physiological processes of living creatures (in this case, humans). These rhythms are influenced by external factors such as light, food intake, and physical activity. The human body has one main circadian clock (the suprachiasmatic nucleus, or SCN), although nearly every cell in the body has its own peripheral clock. Exposure to light serves as the main control for the SCN, while food intake has a major impact on peripheral clocks.

Quite simply, humans evolved with the rising and setting of the sun, and our clocks and healthy physiology are tied to this pattern.” 

To summarize: When it comes to health, biological rhythms matter. Humans evolved with the rise and fall of the daily sun, and breaking with this pattern affects us negatively on a cellular level.

Genetically, some people have a slightly later chronotype (night owls) while others thrive by shifting things earlier (morning larks). Two important things to note on this:

  1. The variability here isn’t huge. Humans are not nocturnal and nobody thrives staying up well past midnight every night.
  2. Chronotypes can be trained. If you have always slept in and stayed up late, then you can feel fine on this schedule, but that doesn’t mean that this is ideal for your health (or that it is without consequences).

That said, let’s be clear about one thing: This doesn’t mean that every single person needs to wake up when the sun rises and go to bed when the sun goes down (this would mean hibernation in the winter for most, which is obviously not possible for modern humans). What it does mean is this:

If you’re having “mysterious” health symptoms that won’t go away, and if you’re the type of person who tends to spend a lot of time indoors, to eat after sunset, and/or to stay up past midnight, then addressing your biological rhythms is a important point of emphasis.

Social Jet Lag

circadian rhythms health canadas nutrition coach3Have you ever stayed up late and slept in on the weekend, only to have to wake up early for work on Monday morning? This pattern is known as “social jet lag, and night owl-types tend to be more negatively impacted because their preferred later sleep/wake schedule is more in contrast with standard weekday work hours.

For example, if you sleep 12am-6am on weekdays, but sleep 2am-10am on weekends, then you’ve more or less shifted your body over 3 time zones (without the travel). As such, not only will waking up on Monday morning be painful, but people with these rhythms are also more likely to be overweight (and with a higher BMI comes a much greater risk for health problems).

Why are we becoming more out of tune with our natural circadian rhythms?

Let’s boil it down to 3 main reasons:

  1. Adolescence trains a bad habit. Human biological systems take ~20 years to fully develop, so teenagers actually thrive on a later night owl rhythm; staying up until midnight and sleeping until 9am actually fits teenage physiology quite well. In our youth we can become accustomed to these types of later patterns and the habits formed here often carry far too late into adulthood. As young, active, hormonally-charged organisms we often “get away” with bad habits re: food and sleep, which subsequently act as the drivers for weight gain and premature health decline in our 20s & 30s.circadian rhythms health canadas nutrition coach
  2. Internet & smartphones. It started with TVs and desktop computers, but we can all now stare blankly at a bright screen in the comfort of our own beds, with an endless flow of entertainment options at our literal fingertips. The advent of these technologies has also made people more accessible than ever, making for longer work hours and social schedules.
  3. 24-hour everything. This goes hand-in-hand with the advent of the internet, but it’s worth specifying. We now have 24-hour access to almost anything: Streaming TV shows/movies, food delivery, gaming, the list goes on. Nighttime is no longer just for sleeping; if you want to be nocturnal, it’s easy to do so.

We have created a world where going outside is no longer a necessity. Many of us now view physical activity as a cumbersome burden. Why walk when I can Uber? Why go to the store when I can have my groceries delivered? Why cook when I can get a hot meal brought to my doorstep? Year after year we’re building in conveniences that make us less and less human: Less physical activity, less time outdoors, less true social interaction and less connection to the natural rhythms of the sun.

What does the research tell us?

The data is quite clear that shift workers have worse health outcomes than the rest of the population (much greater prevalence of diabetes, obesity & metabolic syndrome), but this is an obvious and extreme example.

Regarding standard diurnal rhythms, the majority of circadian research thus far has been done on mice (and is quite compelling in regards to the importance of not eating food after dark). But let’s focus on human studies. Overall, the research paints a fairly dramatic picture regarding night owl-types and those with social jet lag:

  • Poorer sleep quality and duration
  • Higher association with smoking, drinking and less physical activity
  • Higher risk of depression and depressive symptoms
  • Greater risk and severity for developing bipolar disorder or ADHD
  • Higher likelihood of developing binge eating disorder
  • Impaired cortisol patterns and higher incidence of insulin resistance
  • Increased prevalence of type-2 diabetes and high blood pressure
  • Greater body fat and incidence of obesity

While there is still lots of research to be done, it’s already clear that when you attempt to shift your biology away from that of your natural environment, everything becomes an uphill battle. For those who are interested, this research paper succinctly summarizes the human research to date.

The Great Equalizer: Physical Activity

While there is no way to make unhealthy lifestyle habits magically beneficial, regular physical activity can mitigate some of the consequences.

For example, if you routinely go to the gym in the evening, you can train your body to better adopt a later rhythm (provided your sleep cycle is also conducive to this shift). Again, the research does not show that this prevents potential long-term health consequences (relative to people who are tuned to earlier rhythms), but physical activity can seemingly help blunt some negative symptoms in night-owl types.

However, if you rarely exert yourself physically and live with offset circadian rhythms, this is a surefire recipe to promote weight gain, to develop mental health issues and to speed up physical decline.

Zeitgebers: How to Entrain Strong Circadian Rhythms

German for “time-giver”, zeitgebers are environmental cues that synchronize human biological rhythms to a 24-hour cycle. As mentioned earlier, the most important of these cues is light, and secondary zeitgebers include things like food, caffeine, physical activity and socializing.

If you’re struggling with body weight or health concerns, adjust your morning to include the following:circadian rhythms health canadas nutrition coach2

  • Wake up with the sun and get bright light on your face ASAP (ideally go outside)
  • Have an early-morning coffee (but none in the afternoon)
  • Eat early and make breakfast your biggest meal of the day
  • Be as active as possible with the bulk of activity in the morning hours

To bring things full-circle, in the evening follow-up your morning habits with these behaviours:

  • Finish dinner as early as possible, with no late snacks
  • Eliminate intense activity and stress after dinner
  • Dim lights and limit screens after dark
  • Be in bed early enough to give yourself a chance at 8 hours of quality sleep

Again, the human research here is young and the mechanisms are not yet fully understood, but correcting misaligned circadian rhythms will result in better sleep, which we know drives the bus for human health processes and immunity.

I’m a parent with young kids, what can I do?

Parenting is a special kind of sacrifice, and you’re a superhero. Kids come first and while sleep can be tough to come by for the better part of a decade, the points above give you a great blueprint to follow once you again have the means to set your own schedule.

In the meantime, accumulate sleep whenever you can, stay as active as possible, and don’t eat after dinner.

Key Takeaways

While there are no one-size-fits-all recommendations for every person, here's what you need to know about circadian rhythms:

  • Humans are no different than other diurnal organisms: We thrive when we live with the sun, we lose health when we break that pattern.
  • If you’re struggling with any deleterious health symptoms, work to shift your daily patterns to be more in tune with the sun: Wake early and front-load your day as much as possible, while having calmer more peaceful evenings.
  • Physical activity remains the key driver for health. If you tend to be more of a night owl, daily exercise is absolutely non-negotiable for health as you age. Our society has gotten wrapped up in the notion that a diet is more important than exercise and this simply isn’t true; for health, you need two to tango.
  • Aside from physical activity, the research is mounting that the single best habit for weight loss and health is to avoid eating after dark.

Over the past century the human race has made incredible leaps and bounds with technology, but at what cost? Emerging research continues to raise red flags regarding the disconnect between said technology and human biology. If your body is giving you signals that something might be wrong, skip the quick fix diet and look at your daily rhythms: Rearranging your schedule could be the key to reconciling your health.









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