Understanding Sleep Cycles

Ever wondered what happens during sleep? At this time, we often go through five stages of sleep. These are known as stages 1, 2, 3, 4, and REM or rapid eye movement sleep. These stages occur in a cycle and we experience all of them whenever we sleep.Of the different cycles, sleep experts say we spend about 50 percent of our total sleep time in stage 2 sleep and about 20 percent in REM sleep. The remaining 30 percent, on the other hand, is spent in the other stages. With infants it’s a different matter; they spend about half of their sleep time in REM sleep. What happens in each of these stages?

In stage 1, we drift in and out of sleep. This is known as light sleep since we can be awakened easily. Here the eyes move slowly and there is slow muscle activity. People awakened during stage 1 sleep usually remember fragmented visual images.

In stage 2 sleep, eye movements grind to a halt and brain waves are slower except for occasional bursts of rapid waves known as sleep spindles. With stage 3, even slower brain waves called delta waves appear together with smaller, faster waves.

When stage 4 arrives, all we see are delta waves. Stages 3 and 4 are collectively known as deep sleep. At these stages, it’s hard to wake someone. Eye movement and muscle activity are absent. People awakened at this time usually feel groggy and disoriented.

During REM, breathing is more rapid, irregular and shallow. The eyes move rapidly and limb muscles become paralyzed for a while. At this stage, brain waves increase at levels similar when a person is awake. The heart rate increases, blood pressure rises, and men have erections. This is the period when dreams usually happen. If someone wakes you during REM sleep, you can easily remember your dreams.

Understanding this stages will help you find a better sleep. As we all know having a right sleeping habit will give you more strength and clear mind to do your daily activities. Always make a habit to have a right amount of sleep!