Each night when you go to sleep, your body and mind goes through a lot of changes.

This is why it seems like you are in a lighter or deeper sleep, or sometimes you dream and other types you don’t. Each of these changes will occur during a different stage of sleep.

Here are the stages of sleep and what you can do to improve them.

Stage One – Light Stage Sleep

The first stage of sleep is naturally the lightest sleep, which is often what people experience when they take a brief nap in the daytime. Even at night, you go through stage one first, but it can last just a few minutes.

During the light stage of sleep, your eye movements will start to slow down, and while you are slightly unconscious, you are also a little alert.

If you have ever drifted off while in bed or lying on the couch, but are instantly alerted to what’s going on a minute or two later, you were caught in the first stage of sleep.

Some people have jerky body movements as well, especially when going between stage one and two of sleep.

Stage Two – Preparing for Deep Sleep

When you get through stage one, you start preparing for a deep sleep.

This is stage two, when your eye movement has stopped and your brain waves start to slow down.

Your body temperature will also likely drop in order to prepare for a deeper sleep.

Stage two is still a lighter sleep since you are not yet in a deep sleep yet.

Your heart rate slows down, and there is an increase in brain wave activity.

If you are trying to take a short nap, you wouldn’t want to get past stage two, or it would be hard to wake back up without an alarm.

Stage Three – Beginning of Deep Sleep

The start of a deep sleep occurs in the third stage of sleeping.

Your brain produces waves called slower delta waves, which is when you might start having night terrors or other effects of sleep if you have a parasomnia.

Do you struggle with sleepwalking or talking in your sleep? If so, it will probably occur in stage three or four, but rarely during REM sleep (the final stage).

When you reach stage three of sleep, it is harder to awake you.

You won’t be as responsive to sounds and other distractions, only waking to a loud noise or other sudden alert.

You might not even hear your alarm clock right away.

Stage Four – Continuing Deep Sleep

The final stage of sleep before you reach REM sleep is stage four, where you continue with your deep sleep.

Your brain is still producing those delta waves, though it is more continuous and long-lasting than in stage three.

If you are woken up while in stage four of sleep, you tend to be very sleepy and a bit disoriented.

REM sleep is important for everyone. It helps you process information from the previous day for long-term storage, and it helps your body to fully rest.

REM Sleep – Rapid Eye Movement

Finally, you reach the fifth stage, which is REM sleep. This stands for rapid eye movement, which is the deepest form of sleep.

It typically occurs between 1 and 2 hours after you have fallen asleep and gone through the other 4 stages of sleep.

When you have an REM sleep cycle (Which there are several each night), you might have dreams, and if someone were to look at your eyelids, they would see your eyes moving back and forth. Your heart rate increase and your breathing is sometimes faster.

If you never dream, you might not be getting REM sleep, and should get help with improving your sleep throughout the night.