WHAT IS THE CIRCADIAN RHYTHM?
Everyday, even if we do not set an alarm, we seem to be able to wake up at around the same time. This is because we have a built-in body clock that repeats every 24 hours. This allows our body to subconsciously know what time it is. This clock is called the circadian rhythm. Due to this rhythm, even if we were kept in total darkness, we would continue to behave by a cycle of about 24 hours.
This body clock also affects behaviour in plants and other animals. For example, barn owls use their circadian rhythm to sleep during the day and hunt for food at night. Similarly, many plants also use their body clock to move to face the Sun in the sky. This maximises the amount of energy they can absorb from it, helping them to grow.
WHY IS IT IMPORTANT TO HAVE A BODY CLOCK?
The circadian rhythm is very important in allowing the body to predict what our needs will be at a certain time. For example, if somebody eats everyday at 8.00am, the body can prepare for this by producing more digestive juices to break down the food quicker.
The importance of the body clock can be seen by considering people whose circadian rhythm does not work. For example, some people may have a daily rhythm that lasts 25 hours or more. This means they sleep and wake-up one or more hours later than the previous day.
WHERE IS THE BODY CLOCK?
Many parts of the body have a separate clock to allow a particular organ to change its activity during the day. These individual clocks are controlled by the body’s master clock, located in a special part of the brain called the hypothalamus. This region in the brain has connections to our eyes, meaning our master body clock is matched to the light levels around us.
HOW CAN THIS CLOCK AFFECT OUR HEALTH?
The circadian rhythm predicts what will happen during the day. If we keep changing what we do at a certain time, it can confuse this master clock. This can upset the rhythm of our body and cause different organs to act out-of-sync with one another. This can lead to health problems such as cancer, heart attacks and diabetes. In order to prevent this, we should make an effort to maintain a similar routine everyday. For example we could try going to sleep, exercising, eating and studying at the same time every day!