Sleepy and Tired: Finding Your Circadian Rhythm

sleepy tired

Your Circadian rhythm will effect everything from your performance at work, to your mental health

The term circadian comes from the Latin word circa meaning approximately (or about, around) and the word diem meaning day. The circadian rhythm as is referred to in this article is the daily biological rhythm of the human body. This rhythm is built in and is based on a 24 hour cycle, but is adjustable depending on the environment. The 24 hour cycle is perpetuated by something termed the circadian clock, and is broken down into a basic day-night or light-darkness periods. Environmental cues called zeitgebers (German for synchronizers) can switch the clock around, the strongest cue being sunlight.

What’s the default setting of our circadian clock?

As our planet is rushing through space and spinning around its axis the beginning of nighttime and daytime are changing constantly, as are the durations of time and day, and our internal clocks are readjusted accordingly. We are active and energetic during the day and we get tired and go to sleep during the night. It’s important to note that exercise can also affect the circadian rhythm. There are several components that define a circadian rhythm:

  • They repeat at 24 hour intervals

  • They rhythm persist even when external cues are absent (in isolation, periods of darkness in areas near the poles, etc.)

  • The rhythm can be adjusted to local time (hence the jet lag people who travel across different time zones experience)

  • The rhythm is maintained over a range of physiological temperatures

The way this works normally is that the person experiences the following changes throughout the day.

  • 06:45 – the sharpest rise in blood pressure

  • 07:30 – secretion of the hormone melatonin (the one that makes us sleepy) stops

  • 09:00 – highest testosterone secretion

  • 10:00 – high alertness

  • 14:30 – best coordination

  • 15:30 – fastest reaction time

  • 17:00 – greatest cardiovascular efficiency and muscular strength

  • 18:30 – highest blood pressure

  • 19:00 – highest body temperature

  • 21:00 – melatonin secretion starts

  • 22:30 – bowel movements suppressed

  • 02:00 – deepest sleep

  • 04:30 – lowest body temperature

This quite often is not the case in our modern society, where artificial lighting and a need for socialization can keep us up long into the night, even until morning in some cases. The natural flow of things is thus disrupted and we stray from the night-day model.

Why do I feel so tired?

There is a perfectly natural reason to feel fatigued after a workout or after a long day of physical labor, the muscles have been worked hard, there is a build-up of lactic acid, we get dehydrated and we simply run out of fuel. The body needs rest, hydration and food to recuperate. However, we can be tired from running 5 miles or barely able to lift our phone after a workout and still be able to perform mental tasks.

When it comes to dealing with physical fatigue the key is rest, but don’t just take my word for it – Melissa Rollinson, Commonwealth Games silver medalist, a runner and a fitness trainer at I Feel Good 24/7 gyms has this to say on recuperating after heavy physical activity: “Consistent smart training wins the race. I’ve learned how to listen to my body. When to take a break. When I should just sleep in and allow my body to rest”.

The problem is that people who don’t get enough sleep can experience both mental and physical fatigue, even though they don’t really put their bodies through rigorous exercise. The brain becomes sluggish and the person is very irritable. The muscles don’t have lactic acid built up, but the lack of sleep means they didn’t get to properly regenerate during the night. Not getting enough sleep will cause:

  • Impairment of immune system

  • Impairment of memory

  • Lowered cognitive functions

  • Increased irritability

  • Changes in heart rate

  • Higher risk of heart disease

  • Increased risk of obesity

  • Decreased growth

  • Decreased reaction time and dexterity

  • Muscle tremors and muscle ache

  • Hallucinations

You see all sorts of things happen when we sleep, hormones are regulated – the growth hormone in particular is produced in great amounts during sleep, muscles are regenerated, the heart gets a chance to take it easy and the brain is rested. If we don’t get enough sleep and fail to exercise as well, this can lead to massive fatigue during the day. We become mostly worthless at both physical and mental tasks and risk falling asleep at work, or worse at the wheel.

Finding your rhythm

As we already mentioned the circadian rhythm is adaptable, it can withstand minor tweaks and adjustments, but the problem is that by switching our clock to a different time zone while staying in our old time zone physically means that we are going to have trouble working with other people. If your job requires you to be at the office by 9 am, highly alert and functioning at optimum capacity by 10 am, and you are operating on a cycle that considers 2 o’clock pm to be the start of your day, you are in some serious trouble. The average adult needs about 7-8 hours of sleep during a 24 hour cycle. This means you can adjust your sleep patterns by carefully choosing the time you go to sleep and having the willpower not to sit at the computer or leave the TV on a little longer. Good ways to get yourself ready for sleep are:

  • Some heavy exercise an hour before bedtime

  • Develop good habits – shower just before you go to sleep every night and only lay down in the bedroom only for sleep or sex, this will condition your body to associate these actions with sleep.

  • Relax your brain with some meditation

  • Turn of the computer and the TV about half an hour before going to bed

In this day and age nighttime doesn’t necessarily equal bedtime, and with all the gadgets we have that seem to be only there to entertain us, video games and movies seem more important than a good night’s rest. To avoid risking fatigue as well as some serious health problems, we should strive to get our body’s natural rhythm back by simply getting some more exercise and making a habit out of going to bed. All it takes is some willpower and sticking with our a little ritual of preparing for sleep each night.

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