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Sleep // What is the Circadian Rhythm?

Circadian rhythm refers to your internal body clock. It helps to govern when we feel awake, tired, produce hormones, our temperature, and brain function. This rhythm runs on a 24-hour cycle and is strongly influenced by certain environmental cues; particularly light. Other things that may influence circadian rhythm include timing of eating, exercise, and temperature.

The circadian rhythm controls the production of the sleep hormone melatonin. During the daylight hours, our bodies do not produce much melatonin, but as night and darkness falls production increases. When we are asleep, melatonin production is at its peak, and production decreases to its lowest levels as we start to wake. This process is the circadian rhythm in action.

Before technology, the sun was our primary source of light, which regulated and kept our circadian rhythms in check. In our new, fast-paced world, which is jam packed with artificial light sources such as televisions, cell phones, and computers, it’s not surprising that more and more people are reporting difficulty with sleep/wake cycles.

As already discussed, light has a huge impact on our circadian rhythm, and we can use this to our advantage if there is a disruption in our natural rhythms and resulting sleep quality. By avoiding light sources late in the evening, we can increase our melatonin production, helping us to feel tired and regulating our sleep cycle. However, avoidance of these light sources at night is not always possible. There are now apps that are available to download, which can automatically adjust to daylight and night-time settings, reducing the amount of light exposure.

When our bodies are asleep, our digestive organs are also at rest, meaning digestion of food should be finished before heading off to bed. When we are awake our digestive hormones such as insulin are higher, and melatonin is lower. This process reverses during the evening. This means that we are less able to absorb blood sugar when from food late in the evening. As a general rule you should stop eating around 3 hours before going to bed. So that cheeky, late-night snack could be keeping you awake!

Exercising late at night has been shown to delay wake times and sleep time, whereas exercise in the morning can help us wake early and go to sleep early. Through changing the time when you exercise, you may start to see improvements in your sleep quality.

We can all relate to how hard it is to get to sleep on a hot night or in a hot hotel room!

This is because our body temperature starts to drop as we fall asleep and is at its peak during the day. As such, anything that forces your body to maintain a high body temperature, such as sleeping with an electric blanket on, or a heater in the room, will interrupt sleep. A tip to help you lower your temperature is to have a warm bath. This could seem counterproductive, but by artificially increasing your body temperature before bed, your body will then mimic what should happen naturally by cooling off afterward, helping you feel sleepy.

So, if you feel you need to reset your body clock, remember to minimise light exposure at night, while maximising light exposure during the day, eat at regular times during the day, exercise in the morning and switch off any heaters or electric blankets in the bedroom. Hopefully these tips will see you waking fresh each day after a great, quality night’s sleep!


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