There are lots of factors that contribute to healthy living. But maintaining a consistent daily routine that focuses on healthy habits can help stabilize your circadian rhythms and help you achieve optimal health.
What are circadian rhythms & why do they matter?
Circadian rhythms are the physiological changes that take place in your body over the course of a 24-hour cycle. They are regulated by collections of genes and proteins referred to as “body clocks.”
Your master & peripheral body clocks
The “master body clock" resides in a part of your brain called the suprachiasmatic nucleus (SCN). The SCN is the first body clock to get thrown off by things like jet lag.
The clock in the SCN is perhaps the most well-understood body clock, and it’s affected primarily by light / dark signals, that play a predominant part in controlling your sleep / wake cycles, when hormones are released for ovulation and digestion, and when it is time for your body to sleep so that your muscles can rest, your body can heal, and your immune system can get stronger.
Wow - that's a lot of responsibility.
Additional body clocks, called “peripheral body clocks,” exist in other body organs and tissues, such as the liver and pancreas. For example, the body clock in your liver governs detoxification, and the clock in your pancreas regulates insulin production.
All of your body clocks work in synchrony to create circadian rhythms that regulate hormone release, metabolism, digestion, and immunity.
The master clock in the SCN regulates the activities of your peripheral clocks, and your peripheral clocks interact with one another and provide feedback to your master clock. Together, these internal mechanisms generate your circadian rhythms.
The gut-circadian rhythm connection
What’s also interesting is that we possess a “24 hour” intestinal body clock. The rhythms of this intestinal body clock affect your absorption of nutrients, metabolism and immunity. Your intestinal body clock also communicates with the SCN in your brain, your pancreas, and your liver.
Plus, bacteria living in your gut have a profound influence on the intestinal body clock, which as just mentioned affects all of the other clocks.
Yes, additionally your gut bacteria also have a daily routine i.e. circadian rhythm, so the health of your gut microbiome not only impacts your other body clocks but also its own microbiome clock. It’s so clever - how everything is interconnected and interdependent in these amazing bodies we live in.
The impact of disrupted circadian rhythms on gut health
With circadian rhythms in the intestine, pancreas, and liver being crucial for regulating metabolism, insulin release, body weight, and detoxification, it does however mean that a disrupted microbiome can throw off metabolism, cause insulin resistance, weight loss resistance, and impair detoxification.
Considering the body as a whole is therefore always best policy when looking to optimize your health.
In terms of gut health, disturbance of the circadian rhythm caused by abnormal sleep / wake cycles and eating schedules can also weaken intestinal cells increasing the risk of damage within the gut, and gastrointestinal disorders such as leaky gut (intestinal permeability), and irritable bowel syndrome (IBS).
Disrupted circadian rhythms may also increase the risk of gastrointestinal infections by decreasing immune function, which normally defends the gut against pathogens. (1)
This really emphasizes just how important lifestyle is to your overall health.
Circadian rhythms influence your immune system
A critical role of your circadian rhythms is to regulate healthy immune system function.
A healthy immune system is one that maintains a constant and balanced internal environment, which requires persistent monitoring and adjustments as conditions change within your body. It’s also one that responds well to immune challenges, for example defending against viral and bacterial threats.
Additionally, your body has intrinsic clocks within the cells of your immune system that regulate their function, influencing the way in which they respond to harmful attacks.
However, rhythmic signals from other body clocks also drive rhythmic behavior in your immune cells.
We know that the majority of our immune system lives in the gut, so it makes sense that gut microbiome and its circadian rhythm also has a major influence over immune system function.
Vagus nerve and circadian rhythm
Something else, a major cause of vagus nerve damage is due to circadian rhythm dysfunction. As the vagus nerve is the primary component of your parasympathetic nervous system (rest and digest, or feed and breed response), it, as a consequence plays a key role in your heart rate, breathing rate, digestion, detoxification and much more.
So, circadian rhythms are a big deal. And I cannot emphasize enough the benefits of staying in a consistent daily routine - centered around constant sleep, wake, and meal times.
The positive impact on your health is massive and it can be achieved with a few simple shifts to your lifestyle habits. Here’s 4 lifestyle habits to help you stabilize your circadian rhythms and optimize your health.
4 lifestyle habits for healthy circadian rhythms
While the circadian rhythm is susceptible to disturbances, the good news is that it can be brought back on track with simple lifestyle changes like these:
1. Get natural light exposure
It's important that you expose yourself to natural, outdoor light, especially in the morning and throughout the day, even on cloudy days.
Getting five minutes of sunlight first thing in the morning can reset the suprachiasmatic nucleus (SCN) in your brain and help with better hormone regulation.
Spend more time outdoors where you can. Then, when evening falls, start dimming the lights inside your home and make sure your bedroom is completely dark (no TV or LED screens) in the run up to sleep time.
2. Review your diet & eating schedule
While light exposure and temperature are the primary signals that affect the master body clock in the brain, gut circadian rhythms are primarily influenced by the timing of food intake and diet.
Erratic eating patterns, such as snacking all day, skipping meals or eating late at night, disrupts the circadian rhythms of gut bacteria.
Their journey throughout the gut becomes disorganised, leading to disruption of the intestinal body clock and an overall disconnection of circadian rhythms in your body. (2)
Likewise these habits can also disturb intestinal cell circadian rhythms which have systemic effects on the body.
To support healthy gut circadian rhythms it’s best to eat breakfast in the morning, when cortisol is at its highest. Meal timing should coincide with a predictable rise and fall of cortisol and other hormones.
Eating with your natural sleep / wake cycles helps to balance your hormones. This means your last meal of the day should be no later than 7pm, although ideally earlier if you can.
When it comes to diet you’ve probably already guessed that meals packed with nutrient dense, whole-foods will serve your body much better than processed food, or meals lacking a healthy balance of macronutrients.
3. Manage your stress levels
Your circadian rhythm, internal clocks and the regulation of all biological systems are intricately connected to the stress response.
Higher stress levels alter your stress hormones and your melatonin levels (which kick in as darkness falls), leading to more dysfunction of your circadian rhythm and internal clocks.
Take walks in nature, exercise regularly, make time for mind and body relaxation and limit your intake of negative news. These are all ways to help keep your stress levels in check.
4. Practice good sleep hygiene
Artificial lights, too much screen time, and unpredictable sleep schedules can all negatively affect your natural circadian rhythms and throw your hormones out of whack.
The more regular your sleep, the better regulated your circadian rhythms will be. Here are a few ways to improve sleep hygiene:
- In the evening, make sure your bedroom remains dark, quiet, and free of electronics.
- Engage in relaxing activities—like reading or journaling —for an hour before sleeping.
- You can also use special bulbs in your bedside lamps that filter out blue spectrum light. This will allow for the natural rise of your immune-activating hormone melatonin.
- Don't take daytime naps longer than 20 to 30 minutes.
- Avoid caffeine in the evening and limit caffeine consumption during the day, if you think it’s disrupting your hormones and sleep.
- Stick to a consistent schedule for falling asleep and awakening, only varying by one hour every now or then (like on the weekends and holidays).
In summary, it’s no surprise that circadian rhythm disruption has negative health implications. It can contribute to sleep disorders, metabolic, digestive and cardiovascular dysfunctions, mood disorders, and other disruptions that affect your well-being.
The main causes of circadian disruption are changes in your major cycles: the light–dark, sleep–wake, and feeding–fasting cycles.
As much as you can, try to create simple habits that help to support your circadian rhythms.
If you’ve found this post helpful, or made any changes to your lifestyle to support healthier circadian rhythms, do share your experience below in the comments section.
Hi, I'm an Integrative Nutrition Health Coach, Pain & Stress Management Therapist, and Certified Functional Medicine Practitioner.
I help people elevate their mind and body health by addressing diet, nutrition and lifestyle symptoms. Let's work together to optimize how you feel and function.
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