Sleep

The Biological Clock

​

Every cell in the human body has its own biological clock. These clocks are aligned to the 24 hour cycle of light and darkness that occurs due to the rotation of the Earth.

​

This regular daily cycle is called the circadian rhythm. The circadian rhythm aligns our sleep and wake cycle with the light and darkness cycle of Earth so we feel awake during the day time and feel tired at night time.

​

Circadian rhythms influence many aspects of the human body. Without this internal clock that matches a 24-hour interval, our sleep cycles, hormone balances, body temperature, blood pressure, eating habits, and various other bodily functions would suffer.

​

All living things have biological clocks and these are essential for most life to function on Earth. From animals, plants and even microbes, they all adapt to daily light and dark cycles, as well as seasonal ones when the daylight hours are either longer or shorter.

​

Master Clock

The various biological clocks in the human body are synchronised by a master clock which is located in a tiny region of the brain, called the suprachiasmatic nucleus (SNC).

​

The SNC receives information about sunlight from cells at the back of our eyes, called photoreceptors. These signals are processed to coordinate the clocks within every cell in the body, so that they are synchronised with the light-dark cycle of Earth.

​

Using sunlight, the SCN can adjust the circadian rhythm to gradual changes in daylight hours as we progress through the seasons too.

​

The SCN also produces a hormone that makes us sleepy, called melatonin. When there is less light at night, the SCN tells the brain to make more melatonin so you feel drowsy.

​

The Human Body & The Environment 

Changes in our body and environment therefore can cause our circadian rhythm and the natural light and dark cycle to be out of synchronisation.

​

Things like jet lag, light from electronic devices used late at night, mutations or changes in our genes, and late night shift work, can all lead to sleep disorders, and may lead to other health conditions, including;

​

• Acid Reflux

• Adult Asthma

• Breathing Troubles

• Liver Problems

• Fatigue

• Low Blood Oxygen Levels

• Type 2 Diabetes

• Depression and anxiety

• Memory Loss and mental confusion

• Weight Gain & Obesity

• Weakened Immune System

• High Blood Pressure

• Heart Problems

• Stroke

• Abnormal Cholesterol

• Trouble Concentrating

• Increased Stress, emotional distress, feeling Unwell

• Poor physical performance and coordination

• Increased risk of some cancers

• Worsening of existing medical conditions

​

​It is therefore very important to ensure that we get adequate sleep and have a regular circadian rhythm, to help keep our bodies and minds healthy.