The Science Behind your Sleep Cycle – Your Inner Body Clock

Your sleep cycle is an important mechanism. It’s responsible for:

  • Sending you to sleep at night
  • Maximizing the quality of your sleep
  • Waking you up in the morning feeling refreshed
  • Keeping you wide awake and alert during the day

By learning how your sleep cycle works, you’ll understand the steps you can take to make your sleep cycle work even better and keep your sleep pattern on track.

How your sleep cycle keeps track of time

You have a clock inside your brain in the part called the hypothalamus. It’s located just behind your eyes. The job of this clock is to regulate daily bodily cycles. This includes your sleep/wake cycle, also known as your circadian rhythm.

Your internal body relies on outside events to figure out what time of day it is and keep it on track. These outside events are known as ‘time cues’, or more technically ‘zeitgebers’, a German word meaning ‘time givers’. Without these daily time cues, your body clock will drift off track.

Sleep CycleThe biggest time cue is sunlight. When it’s dark, our circadian rhythm makes us sleepy. When it’s light, it keeps us awake. This time cue worked great in the past. Although the amount of daylight varied with the seasons, it was a highly reliable way of telling the time. But in modern times, our body clock can confuse electric lighting with sunlight, causing us to stay awake longer unable to fall asleep.

Other time cues include meal times and regular social events. Practically any daily event that occurs at a regular time can be used as a time cue.

How your sleep cycle changes during the night

Your sleep cycle’s job isn’t over once it’s sent your body off to sleep. Sleep isn’t just a state of inactivity. To get good quality sleep, your sleep cycle is required to shift between various stages of sleep during the night.

When you first drift off you go into NREM sleep. Your sleep starts very light and then gets progressively deeper. Essential bodily maintenance takes place whilst in the deepest stages of sleep. After around 90 minutes, sleep slowly becomes progressively lighter again.

The next stage of sleep you go into is REM sleep. The brain is very active during this stage of sleep. This is the stage where dreams occur. During this time your brain moves select memories from short term storage into long term storage. It’s essential for learning new skills. After around 15 minutes you go back into light NREM sleep.

Sleep continues this cycle during the night. Your first round of NREM sleep is the deepest. Further rounds of NREM sleep won’t be as deep as the last.

Because sleep is deepest when we first fall asleep, it’s possible to maximize your sleep by changing your sleep pattern so that you sleep multiple times during the night. One sleep pattern consists entirely of 20 minute power naps spread out throughout the day. Doing this boosts your sleep quality so you can fulfill your need for sleep in far fewer hours. The downside is that these alternative sleep patterns are extremely hard to stick to. If you’re curious about alternative sleep patterns, head over to the sleep patterns article.

How to make your sleep cycle work even better

By optimizing your sleep cycle you can both:

  • Increase the efficiency of your sleep – Fall asleep faster at night so you spend more time in bed sleeping and less time being awake.

  • Maximize the quality of your sleep – Spend more time in the deeper stages of sleep so you wake up feeling refreshed and alert.

Here are a few quick tips to get the most out of your sleep cycle:

  • Get plenty of sunlight during the day – Sunlight makes you feel more alert. Open the bedroom curtains as soon as you wake up in the morning and get outside during the day when possible. If it’s dark and gloomy outside, consider using light therapy.

  • Avoid bight light during the night – Curtail your intake of light as the night progresses. At least 30 minutes before bed don’t use any light emitting devices such as TVs, smartphones or tablets. The light from these devices lengthen the time it takes for you to fall asleep.

  • Stick to regular mealtimes – Mealtimes are the most important time giver after light. The more regular your meals, the more consistent your sleep schedule will become. Avoid eating a large meal to close to bed since doing so can prevent you from sleeping.

  • Avoid caffeine, alcohol and nicotine before bed – All of these reduce the amount deep sleep you get during the night. The less deep sleep you get the more likely you are to wake up in the night and feel sleepy in the morning, even if you did get your recommended hours of sleep.