Why Your Body Clock Is The Crucial Awareness Switch Between Sleep, Health and Fatigue?
Sleep is regulated by two body systems, sleep, wake homeostasis and the circadian biological clock.
When we have been awake for a long period of time, sleep and wake homeostasis tells us it’s time to sleep…
Your body uses this internal clock, which makes you feel sleepy at night and awake during the day.
Even though there are 24 hours in a day…
Your body clock is actually on a slightly longer cycle of 24.1 hours.
Being exposed to sunlight adjusts the clock so it stays aligned with day and night
This internal clock is controlled by a part of the brain called suprachiasmatic nucleus (SCN)
When this clock tells your body to sleep a hormone called melatonin is kicks in…
What Makes You Tick?
It might surprise you to know that your brain has a kind of clock in it.
This keeps your body ticking over every day.
As humans, we prefer to sleep at night and be up during the day.
This isn’t a result of particular behaviors, habits, work schedules or conveniences…
Every Process is Driven By The Body Clock…
Even if we don’t know what time it is, we still do things in cycles that go for about 24 hours.
We sleep for part of every 24 hours, our body temperature rises and falls with a cycle length of about 24 hours.
We have hormones and other systems in our body that go through this daily cycle as well.
Exactly the same pattern is seen in almost every living organism on the planet.
We all have an internal body clock which controls when we can do activities…
The daily rhythms are known as circadian rhythms.
Circadian rhythms affect our energy levels, health and well being depends on this ticking all the time.
Your body clock needs to tick at the same sequence or rhythm of time as everything around us.
This is called being ‘synchronised’…
Where is the clock?
Scientists have known for a long time that daily rhythms are driven by some kind of clock in our bodies.
But they didn’t discover exactly where it was until the middle of the 20th century.
They found this out when they experimented and did surgery on hamsters…
They took out a tiny part of the hamster’s brain called suprachiasmatic nucleus (SCN).
After this, the hamsters totally lost their rhythm and not just on the hamster wheel.
It used to be easy to predict when the hamsters would run on a wheel.
But after they lost SCN, they ran at any and all times of the day and night.
That was the first big step in understanding…
How Does SCN work?
How the rhythms are produced is complex.
We can simplify the process as follows:
Specific clock genes in the SCN switch on which cause proteins to be made.
As these proteins accumulate along with other chemicals, they’re responsible for regulating and switching off the clock genes.
The level of proteins then drop to point where genes are able to switch on again…
And the cycle restarts…
This cycle of switching off and on happens about once every 24 hours.
The SCN sends out signals to the rest of the body that vary according to this cycle.
The cycle is not just determined by the SCN itself…
SCN responds and adapts to signals from outside the body.
The biggest factor is light and dark in order to keep us synchronised with the world…
That means, you’re either ticking at the right time or out of sync with your body and environment.
Is Light Important To How The Body Clock Works?
The most important external signal for the biological clock is light.
When the eye senses light, it sends signals to the SCN.
This resets the body clock every day…
Our body does this to make sure rhythms don’t drift out of line with the environment.
Although our rhythms cycle about once every 24 hours, without light and dark (for example, total blindness) humans actually tick a little more slowly about 24.1 hours.
If we didn’t have daylight we would get out of synchrony with night and day.
People with delayed sleep phase syndrome have trouble adjusting.
They go to bed and wake up later…
This can be inconvenient when you’re trying to schedule workouts or activities such as work and school.
Shift workers often have trouble totally adjusting to being up at night and sleeping in the day.
The external light and dark cycle and tends to keep them on a day shift pattern.
The influence of light also explains why we can adjust to a new time zone if we fly abroad.
The light in new time zone sends a signal to our body clock, which causes it to get synchronised with new time zone.
This usually takes several days to adjust…
Of course, while we wait for adjustments, we suffer from symptoms of Jet Lag.
Not much fun, especially if you add stress and mental fatigue to the equation.
Why Is The Body Clock Important For Sleep?
The cycle of sleep and wake is one of the most important circadian rhythms in humans.
Sleepiness is highest at night and lowest in the day.
At night, we get the best quality sleep and longest blocks of sleep without waking up.
Sleep during the day is more broken up. It tends to be lighter as well.
This means we sleep less…
Melatonin and body temperature are also driven by the body clock.
These are also well known circadian rhythms.
At night, core body temperature is low and levels of melatonin are high.
Getting these rhythms aligned with each other as well as the external environment gives us the best chance for good quality sleep, better health and well being.