For many years, I was a “night owl”? I thought I got by pretty well on just about five hours sleep, but it caught up with me. When I tried to reset that biological clock inside me, it required a little research.

There is a little bundle of nerve cells in the front of your brain called the suprachiasmatic nuclei. It is responsible for many timing functions in mammals. One thing we share with most animals and plants is biological rhythms. Also known as circadian rhythms, it’s our biological “clock” and it controls things like our body temperature, alertness, appetite, and hormone secretion.

We probably have other controls in our genes, and it seems that all living creatures run on several different biological clocks simultaneously.

It also affects our sleep timing. It might surprise you that sleepiness does not continuously increase as time passes. Your sleepiness – desire and ability to fall asleep – is influenced by how long it has been since from your last good sleep, but also by circadian rhythms.

When people have sleep problems because of circadian rhythms, it’s about the timing of sleep. If your clock is off, you can’t sleep and wake at the times required for a normal day.

Of course, what is a “normal” day? Even if your circadian clock is right, normal is a continuum.  Scientists recognize chronotypes – “larks” or “morning people” and  “owls” or “night people.”

The biological clocks inside us make it possible for us to recognize the passage of short intervals of time, but others (like in our retina) respond to light and regulate our bodily functions over 24 hours and even longer cycles.

Time may be a human construct, but our perception of time depends very much on things like light and your body temperature.

How does we “reset” our clocks? People who switch to working a night shift from a day shift are able to do it.

There are simple treatments: avoid naps, caffeine and other stimulants. A sleep diary (like a dream journal) where one records sleeping and waking times with related information creates an awareness that is helpful and may even allow you to do some self-diagnosis.

Actual treatments use light therapy to advance or delay sleep. It’s a technique that also gets plants to bloom on a controlled schedule, and gets chickens to lay eggs more often.

Additional Reading
Rhythms of Life: The Biological Clocks that Control the Daily Lives of Every Living Thing