Have you ever wondered why you usually wake up fully recharged and much revived after a full night’s sleep? It’s because while you’re sleeping, your muscles are restored, your mind processes the various inputs of the day, and your entire immune system, along with the other essential functions of your body, is revitalizing itself.

It would be up to you to complete several sleep cycles during the night so that you can wake up in the morning feeling like you have achieved a satisfying feat. Sleep cycles are made up of the different stages of sleep that are commonly experienced by all of us.

Waking

When you’re awake, your brain is quite active. Your brain waves have a high frequency, which means that they appear close together on the graph, and a low amplitude, which means that they are short on the graph, without large spikes. Brain waves don’t follow a regular pattern; instead they change continuously as you progress through your day. These waves of the brain are called Beta waves. When you relax your brain waves, they become more regular. The amplitude is increasing, and the frequency is slowing. These waves of the brain are called alpha waves.

What are the various stages of sleep?

Sleep can be categorized into about four stages, according to the American Academy of Sleep Medicine. Sleep experts say that we spend about 50 percent of our total sleep time in stage 2 sleep and about 20 percent of our total sleep time in REM sleep. The remaining 30%, on the other hand, is spent in the other stages. It’s a different matter for infants; they spend about half of their sleep time in REM sleep. What is going to happen in each of these stages? During the night, we rotate through a complete sleep cycle several times until we finally wake up the next day. Starting with stage one, moving through stage 4 of the REM (Rapid Eye Movement), and then back to stage two to start the cycle. The first stage is usually skipped for the rest of the night.

STAGE 1

The magic begins when your tired head hits the pillow with your eyes closed, and your wondered thoughts begin to tap into the distance. This is the first stage where you’ll find yourself drifting in and out of sleep. This stage is the lightest of all of them and can be interrupted easily. It’s a transitional period of slight unconsciousness that can be compared to a day of dreaming experience. Those who practice meditation find themselves in a place similar to the first stage of sleep. In fact, many of us don’t realize that we’re already there, and if we were awake, we probably wouldn’t feel like we were sleeping. The length of this stage is relatively quick, depending on the person and their surroundings, and whatever interruptions you may face, usually around 20 minutes or so.

STAGE 2

The second stage, which also lasts about twenty minutes or so, slows your eye movement to a halt. Your brain waves slow down as you experience the occasional burst of rapid activity. Your breathing stabilizes and becomes more rhythmic as you become even more disconnected from your surroundings. Your heartbeat begins to slow slightly, and your temperature drops as your body prepare for a deeper sleep.

STAGE 3

With the onset of this third stage, the last of the non-REMs often lasting around forty minutes or longer, our brains experience deep slow waves known as the Delta Waves and will eventually experience these almost exclusively as minutes of progress. Your blood pressure will go down, and your breathing will be slower. Your muscles become a little relaxed while your blood supply increases. This deep sleep is the most restorative in which growth hormones are released, and tissue repair is performed.

Due to the deep sleep experience at this stage, it is often particularly difficult to wake someone up during this time. Sleepwalking and bed-wetting will usually take place during this sleeping stage. Night Terrors can also occur at this time, not to be confused with nightmares that are distinctly different. A night terror is a sharp partial awakening that can lead to behaviors such as thrashing or kicking, screaming or muttering, and rarely come with the recollection of these events the next day. In order to be fully rested, you will need to take several doses of the third stage, as this is often considered to be the most important.

STAGE 4

REM This is the stage where the name is known to everyone. REM, which stands for Rapid Eye Movement, is just what it sounds like, your eyes jackass and dart around fast during this stage. Your breathing becomes irregular, shallow, and faster. Your heart rate and blood pressure are also increasing. Unlike in previous stages, your muscles usually do not move, and your limbs become temporarily paralyzed. However, your brain waves increase to the level of someone who is wide awake. REM sleep gives energy to your body and brain and has a direct impact on your daytime performance.

This dramatic increase in brain activity often leads to dreams or even nightmares that we do not experience at any of the other stages. Although we may have a passing memory or image of something from one of the earlier stages, dreams only happen during REM sleep. Interestingly enough, the duration of your dream is usually relative to how long you seemed to have dreamed. If you’ve had a long, vivid dream, you’ve probably been dreaming for a long time. As you rotate through your cycles as the night progresses, stage four will usually last a little longer than before. From here, we’re going back to stage two to continue the cycle again.

To avoid any disturbances in your sleeping cycles or problems relating to the inability to reach the first stage of sleep, it is very important to establish a regular sleeping routine or pattern. Learn to break the habit of drinking caffeine or alcohol and smoking close to bedtime. Since sleep would only occur when you are relaxed and composed, make it a point to de-stress long before bedtime by different means, such as meditation, breathing exercises, and other soothing activities that will help in naturally inducing sleep.