Mastering Your Circadian Rhythm

From the very beginnings of life on earth, there has always been one thing so constant you can literally set your clock to it: the sun.

No matter how many changes this planet has been through, you can always count on the sun rising for the morning and setting for the night.

Because of this, it should come as no surprise that humans – as well as just about every other species on this planet – have strong biological responses to the absence or presence of sunlight.

Pretty much all of our organs are in some way affected by our biological clock, which causes changes in our body over a roughly 24-hour cycle known as the “circadian rhythm.”

Understanding how your circadian rhythms work can have a massive impact on your health and happiness, so it’s important to be informed!

Image: rosy-fingered dawn streams out across a meadow

What Is a Circadian Rhythm?

Coming from the Latin circa (“about”) and diem (“day”), the term “circadian” can be applied to any number of our body’s daily rhythms.

All across our body, cells function like clockwork as they anticipate the circumstances they’ve become accustomed to dealing with at certain times.

From your liver and pancreas to the trillions of bacteria housed in your gut, pretty much every part of your body is hooked up to some kind of daily cycle.

The grand poohbah of all this activity is a cluster of some 20,000 neurons in your brain called the suprachiasmatic nucleus (SCN), also known as your body’s “master clock.”

This tiny region of the hypothalamus controls the release of a whole cocktail of hormones that have an impact on bodily functions – the most famous and arguably most important of which is sleep.

 How Your Sleep/Wake Cycle Works

The circadian rhythm of sleepiness and wakefulness is influenced by rising and falling levels of various hormones throughout the course of the day,

In general, most people experience two main dips in energy every 24 hours.

The smaller one happens in the middle of the day, around 1 to 3pm.

This is what makes you so tired just after lunchtime, and in hunter-gatherer societies (as well as some parts of the developed world today), this is generally the time a lot of people use to power down for a nap.

(The hours between 1 and 3 are also ideal for a genuinely energizing power nap that won’t mess up your sleep schedule!)

The bottom of the larger dip in energy happens in the middle of the night, typically between 2 and 4 in the morning.

Of course, you’re going to start feeling tired long before that point, often starting around 10pm.

Keep in mind that some people are biologically more likely to be night owls, while others are most definitely early birds.

Even if everyone around you is waking up at the same time, some people’s clocks are simply set earlier or later than others.

Additionally, your sleep/wake cycle obviously can also vary based on your environment.

 The typical college student’s life style, after all, is not going to be at all like their grandparents’.

(As we age, in fact, we all find ourselves needing progressively  less and less sleep.)

Image: girl with a sleep mask and cup of tea looks incredibly ready to go to sleep

Key Players in the Sleep/Wake Cycle

There are a number of different factors involved in the sleep/wake cycle.

Your body temperature, for instance, has been found to play a significant role in getting you settled down for bed.

A cool sleeping temperature increases feelings of weariness, which is why most experts recommend keeping your bedroom thermostat set as close to 65 degrees as possible.

This is also the reason why some claim sleeping naked can lead to better sleep.

There are also a number of factors external to your circadian rhythms themselves, including things like anxious thought patterns, sound levels, and the quality of your mattress.

On the more chemical side of things, meanwhile, you have basically two types of hormone cycles: those that create feelings of wakefulness, and those that create feelings of fatigue.

Wakefulness-inducing hormones, like cortisol, are often linked to stress levels.

Hormones linked to sleepiness, meanwhile, are often available as drugs, either as prescriptions or commercially available drug store items.

The most potent of these is arguable melatonin.

Melatonin: The Secret to Sleep

Cheaply available in pill form on pharmacy wracks nation-wide, melatonin has been celebrated for its role in sleep for many, many years.

Its production in your body is also highly dependent on your exposure to light – hence the chemical’s common nickname, the “hormone of darkness.”

Its production really starts kicking in around sunset, and then gradually amps up to its highest levels in the middle of the night.

As a medicine, melatonin is widely used as a treatment for insomnia, with varying effects.

If you’ve been considering taking melatonin as a sleeping pill, the good news is that there is no scientific evidence to suggest it is any way addictive.

How to Get Healthy Melatonin Levels for Better Sleep

If you’re not suffering from insomnia but are still hoping to develop healthier sleep habits, one of the absolute best ways to get your sleep schedule under control is to regulate your levels of artificial light.

As we mentioned earlier, your body’s clocks are designed to sync up with the rising and setting of the sun.

Light plays a major role in many of your circadian rhythms, but nowhere is this more apparent than when it comes to sleep.

Unfortunately, however, in the modern world night and darkness are no longer as closely linked as they once were.

Until we switch the light off just before going to sleep, most of us have spent our entire evening in light levels similar to those in the middle of the day.

Because of this, many experts recommend reducing artificial light levels as much as possible in the hours before going to sleep.

If you have dimmer switches around your house, turn these down for some nice mood lighting.

Above all, avoid particularly bright lights if you’re trying to get to sleep anytime soon, since these tell your body it’s time to get up and moving.

Image: man looking at his phone in bedWhy Electronics Are Bad for Sleep

Electronics in particular are some of the worst culprits when it comes to disrupting natural sleep cycles.

In addition to keeping your mind awake with distractions when you should really be calming your thoughts, they can have a serious effect on your body’s melatonin levels.

This is because the LEDs used in consumer electronics all rely on short-wave blue light.

Although the biological reasons for this remain somewhat unclear, the human biological clock is more sensitive to blue light than to any other color of light on the spectrum.

It’s shown to suppress melatonin production or even set your melatonin production cycle several hours backwards, resulting in feelings of wakefulness late into the night.

If at all possible, it’s recommended that you avoid looking at your laptop, phone, or TV as much as possible in the hours after sunset, particularly right before you’re going to sleep.

You really shouldn’t be looking at these things in bed under any circumstances – but if you do, you might want to consider either inverting the colors on your screen (many phones let you do this from the drop-down menu), or downloading an app or software that causes your screen to emit only red light.

Our eyes are much less sensitive to red light than to blue, so this won’t disrupt your sleep/wake cycle nearly as much.

Why Midnight Snacks Are Bad for You

Another interesting consequence of our bodies natural rhythms is the way eating habits intersect with our sleep.

Just like with sleep, your body is set to eat at certain points in the day.

If you eat at any time substantially later than when your digestive tract is prepared to deal with you – say, right before going to sleep – you’re forcing your body to put in more work than it’s really designed to do.

The gut has its own clock, and that clock was designed to be in sync with the times you’re waking up and going to bed.

To increase your metabolism and minimize risk of obesity, heart disease, cancer, and other issues, you probably want to be eating your meals in about an 8- to 10-hour window.

Ideally, you really want to start your day out big, with a giant, stomach-stuffing breakfast; eat a smaller lunch later in the day; and finally eat a smallish dinner sometime in the evening.

Don’t try to eat anything after dinner unless you think the hunger is going to make it difficult to sleep, or you risk putting strain or your entire digestive tract by pitting one circadian rhythm against another.

Your biological clock is meant to work as a single, unified whole, and the more we can do to make that happen, the happier and healthier we’ll be.

Conclusion About How to Master Your Circadian Rhythm

Our body’s rhythms incredibly complex, and it’s not really possible to cover everything you could ever need to know about these things in the space of a single article.

Hopefully, however, you now have enough information to make educated decisions about your sleep and health.

Just remember – take care of your body, and your body will take care of you!