What Is Your Circadian Rhythm and How Does It Affect Your Health?

Your body’s circadian rhythm is hugely important for good sleep and most of us know how sleep deprivation saps your energy and motivation, but you may not be quite so aware of how it affects other areas of your health. Researchers now shows 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 and that you’re getting adequate sleep. Here are just a few of the roles that your circadian rhythm plays for wellbeing and what can happen if you mess with your body’s natural rhythms.

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. There are many other things that can cause this energy dip (a heavy lunch, poor sleep, etc.), and we tend to think of it as a bad thing, but it’s a natural part of your circadian rhythm and some cultures honor this by taking a siesta, or early afternoon nap.

The effects on mood 

Sleep disorders can be a symptom of mood disorders and vice versa. 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 for mood and metal health.

Seasonal Affective Disorder (SAD) is an obvious indication of this and research has shown that mice bred to have serotonin dysfunction 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.

Researchers at the University of Glasgow have also found a link between circadian rhythm disruptions and bipolar disorder.

Without sufficient sleep (less than 6 hours), we are in more of a sympathetic nervous system state (aka “fight or flight” - increased blood pressure, stress hormone production, increased heart rate). This can cause anxiety, depression, adrenal dysfunction, reduced Growth Hormone production, and vagal nerve dysfunction/insufficiency.

The effects on appetite 

Disrupting your body clock also has big effects on your appetite and by default, your body composition 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 go down. This is bad news as our bodies rely on leptin to tell our brains that we’re full. The combination means that you’re more likely to overeat the wrong types 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 and lack of quality sleep.

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 more counterproductive, your body also finds it harder to burn calories and build/repair muscle tissue 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. And if you are working out, you may find it harder to increase your strength and muscle mass without enough good quality sleep.

The effects on immunity

Do you get sick a lot? If so, poor quality or not enough sleep could be to blame. During sleep your body essentially replenishes your immune systems’ ammunition to help prevent infection and ward of illnesses. Studies show that the less sleep you’ve had leading up to the time you’re exposed to a pathogen such as a cold or flu, the more likely you are to get sick. 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 mice in the study reacted to infections and whether vaccinations would be effective. 

It’s not yet known whether the same is true for humans but it’s led researchers to question whether you may be more likely to get sick at certain times of the day and whether vaccinations may have more impact if they’re given at particular times.  

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. This opens the door to the possibility of matching blood pressure medications to times of day so that they effectively “reset” circadian rhythms. A potential game changer for people with high blood pressure!

When your body clock is disrupted and/or you are under-slept, your heart rate and blood pressure go up. 

The effects on hormones

Your circadian rhythm affects production of key hormones, including melatonin and cortisol. Your body’s melatonin levels naturally rise in preparation for sleep and fall again in the morning. 

Cortisol is another hormone that can be easily disrupted by changes to your circadian rhythm. 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. 

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. In my next post I’ll share how to create a healthy circadian rhythm and set yourself up for a restful nights sleep.

If you could use some help improving your sleep and feeling more energetic, schedule a complimentary Coffee Talk. Sweet dreams!