Understanding the Stages of Sleep

• Scientists used to think brain activity dropped to nearly zero during sleep but after new technology that idea has changed
• There are five stages of sleep. The first two stages are light. The third and fourth are often where sleep disorders occur. Then the fifth stage is when REM sleep occurs; this is the deepest sleep and is when blood pressure and heart rate increase

Sleep, the precious hours when our bodies relax, heal and regenerate, are some of the best moments of our day even though we aren’t awake to fully appreciate them. However, too many of us aren’t getting enough sleep and that can have a serious impact on our health and our well-being. But how much sleep is enough? That answer lies in learning more about the different stages of sleep that you go through in a single night.

The Five Stages

While we tend to think of sleep as a single step process in which we are either asleep or awake, research now knows that is not the case. This realization is much more recent than you may have imagined. In fact, up until the early 1950’s, scientists thought that brain activity dropped to nearly zero while we slept. Only after the implementation of new equipment was that idea changed, and researchers were able to capture patients in REM sleep (the final stage). Today, five separate stages of sleep are recognized.

In the first stage, which lasts five to ten minutes, you will be drowsy, and your eyes may move sluggishly back and forth under closed eyelids. You can be awakened easily at this point. Interestingly, if you’ve ever had the feeling of falling while you were sleeping, it was most likely during this first stage, as your brain interprets muscle contractions this way and at this point in the sleep cycle.

Gradually, you will move into the second stage of light sleep. This stage is marked by slower brain waves, eye movements stop, body temperature will change, and your heart rate will slow down.

Next, you will enter the third and fourth stages of sleep. Both of these stages are known as deep sleep. The brain is not as active during these stages as the blood flow is directed toward regenerating the body, healing tissues and regenerating energy stores for physical activity. Waking someone up at this point of the sleep cycle is extremely difficult and the person may be confused or disoriented. Many common sleep disorders, such as sleepwalking or bed wetting, occur during these two stages of sleep.

Finally, you will enter the fifth stage known as rapid eye movement or REM. The REM stage means that your sleep duration has lasted for approximately 70 to 90 minutes. It is not uncommon for there to be 3 to 5 episodes of this stage of sleep occuring throughout the night. At this point, there is a dramatic increase in brain wave activity. However, the muscles in your legs and arms don’t move, this is known as sleep paralysis, but it is only for a short time. There is also an increase in the heart rate and blood pressure as well as your breathing becomes rapid, but not deep. During this stage that you start dreaming, and if you are awakened at this stage you can remember those dreams.

These stages are not completed just once during a given period of sleep. In fact, the entire cycle is completed in less than two hours. During each cycle you complete, you go into a deeper sleep during stages three and four and the REM stage becomes longer.

The Importance of the Sleep Stages

Although all of the stages are important, the most important parts of the cycle are the deep sleep periods and the REM sleep. If you have disruptions to your deep sleep – stages three and four – you are going to feel more tired in the morning when you wake up. Impaired sleep during stages three and four means that your body has not been given adequate time to repair and ready itself for the next day. The importance of REM sleep is this is when the body deals with the emotional, memory and stress processing. Having good REM sleep at night has been shown to improve a person’s outlook during the day therefore, having less REM sleep can cause a bad mood. Ensuring that you have plenty of peace and quiet for these stages is important.

If you are still feeling tired in the morning, try getting a few extra hours, here and there, especially if you are sleep deprived. However, to meet the requirements for sleep consistently, you need to set the stage for good sleep on a regular routine. There are specific ways to help determine a regular routine such as: improve your daytime habits, make your bedroom environment inviting for relaxation and sleep, avoid food and drink (especially caffeine) that might impair with sleep, avoid alcohol and some medications, and keep a routine and try to go to bed at the same time each night.

The information supplied in this article is not to be considered as medical advice and is for educational purposes only.