Effects Of Circadian Rhythm On Health + Wellbeing

Your body’s circadian rhythm is hugely important for good sleep and most of us know how quickly sleep deprivation can ruin your health. What you may not be quite aware of is the potential effect on other areas of your health. Researchers now believe that we have lots of different internal body clocks, all of which regulate and control different functions.

From appetite to immunity, you definitely want to make sure that your body’s circadian rhythms aren’t out of whack for very long. Here are just a few of the roles that your circadian rhythm plays for wellbeing and what can happen if you disrupt your body’s natural rhythms too much.

The effects on energy

The dreaded afternoon energy slump is partly due to your body clock. Your body’s circadian wave starts to dip after midday, which can make you tired and lethargic from early to mid afternoon – even more so if your body clock is disrupted.

For your body’s cells to function optimally they need proteins, enzymes, fats, carbohydrates and hormones. These nutrients need to be absorbed, metabolized and produced in a specific rhythm through light + dark exposure and our sleep + wake cycles. When these cycles are compromised, biology is disrupted and we feel fatigue. We are not able to manufacture enough ATP needed to feel energized.

The effects on mood

Sleep disorders can be a symptom of mood disorders. Many people with depression sleep a lot, for example. Levels of neurotransmitters such as serotonin go up and down according to the light-dark cycle and the number of daylight hours, and this is super important to mood.

Seasonal Affective Disorder (SAD) is an obvious indication of this and research has shown that mice bred to have serotonin functioning issues also had disruptions to their circadian rhythms. This can be significant as researchers have found that these type of disruptions can even predict mild cognitive impairment.

A detailed study on how circadian rhythms affect mood.

The effects on appetite

Disrupting your body clock can have big effects on your appetite and by default, your waistline too.

Disrupting your circadian rhythm makes you more likely to overeat and crave unhealthy snacks. Your levels of ghrelin increase, which brings cravings for sweet and carb heavy foods in particular. At the same time, levels of leptin can also go down. This is bad news as our bodies rely on leptin to send signals to say that we’re full. The combination means that you’re more likely to overeat the wrong times of foods. If you find yourself constantly fighting the urge to snack on these kind of foods, it could be due to your circadian rhythm.

Mice who were bred to have a disrupted body clock had big problems controlling their appetite. They snacked a lot and in many cases, they also ate during the night. The mice whose body clocks hadn’t been disrupted only ate twice per day. These findings suggest that the timing of when you eat can be just as crucial as the foods you eat, especially if your body clock isn’t in sync.

And just to make things that little bit more counterproductive, your body also finds it harder to burn calories when you’re not getting enough sleep at the right times. Those extra calories you’re taking in are pretty much destined to be stored as fat, especially if you’re not doing much exercise. Here is a study on circadian rhythms, meal timing and how it impacts energy balance + body weight.

The effects on immunity

Do you get sick a lot? Not getting enough sleep can make this more likely to happen and researchers are trying to work out why. Studies on mice have found that their body clock has an effect on their immunity. In particular, the research found that a protein linked to detecting infections increased and decreased throughout the day. The exact levels of this protein determined how the mice reacted to infections.

This study illustrates how circadian rhythms play crucial roles in physiology and how it is a critical regulator of specific immune functions. Our circadian regulations of immune mediators coincide with the activity of the immune system, allowing us to handle gut-microbial issues more efficiently. They may also promote tissue recovery, and the clearance of potentially harmful cellular elements from our body’s circulation.

The effects on blood pressure

Ever wondered why heart attacks and strokes are more likely to happen in the early morning? Your natural body clock has a lot to do with it as it’s responsible for regulating your blood pressure. When your body clock is disrupted, there can be physical effects too. Your heart rate and blood pressure go up – at times when this wouldn’t happen naturally.

Clinical studies show the importance of the blood pressure circadian rhythm. Loss of this rhythm is associated with an increased risk of stroke and other adverse cardiovascular outcomes. Extensive work from rodent models demonstrates that the molecular clock directly affects blood pressure regulation. This broad array of studies from humans and rodents supports the concept that the molecular clock and its targets located within the kidney, vascular system, heart, brain, and nervous system all contribute to blood pressure regulation.

The effects on hormones

Sleep disturbance negatively impacts hormonal rhythms and metabolism. The levels of growth hormone, melatonin, TSH (thyroid-stimulaitng-hormone), cortisol, leptin, and ghrelin levels are highly correlated with sleep and your circadian cycle.

• Growth hormone levels are increased during sleep and peak immediately subsequent to sleep onset.
• Melatonin exhibits a robust circadian rhythm with levels highest during the biological night versus day.
• TSH (thyroid-stimulating hormone) concentrations reached their maximum during the biological night and minimum during the middle biological afternoon,
• Cortisol’s circadian rhythm level rises rapidly in the middle of the biological night and peaks during the biological morning.
• Ghrelin and leptin promote and suppress food intake, respectively. Ghrelin levels increase prior to habitual meal times and decrease after a meal. Leptin regulates body weight by signaling the brain when you’re full and have enough energy.

Cortisol is another hormone that can be easily disrupted by changes to your body clock. Levels of this stress hormone are raised when you’re awake outside of your natural sleep cycle and this is a big problem for shift workers. Over time, it can affect immunity, metabolism and other functions.

This time of year (January) is typically a bit colder, darker and shorter sunlight hours. Making it a conscious activity to get outside is one of the best things you can do! Start the day with stepping outside and and getting natural sunlight on your face. This tells the body that it is time to be awake! It will boost your cortisol levels to an appropriate range needed to get the energy started for the day. During the day make sure to get out, even if it is for a few minutes to let your body know it is still daytime and to naturally boost your energy levels. Staying indoors too much will alter our circadian rhythms and this sets the cascade of deteriorating health.

As you can see, it’s super important to stick to your body’s natural circadian rhythm as much as possible. You’ll sleep better and most other aspects of your health and wellbeing will benefit too. Your body clock can be disrupted by internal and external factors but there’s a lot that you can do to keep it on track too. Once you begin to make small lifestyle changes the benefits will leave you feeling physically and mentally strong and balanced!

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