Light and Deep Sleep

While some people seem to need a lot more sleep than other people, on average the amount of sleep a person should be getting per night ranges between seven and eight hours. Your body and brain go through different cycles in the night, some of which are made up of light sleep and others of which are deeper sleep. You need both light and deep sleep every night in order to be restored, well-rested, and ready for the next day.

The Difference Between Light and Deep Sleep

During sleep, the body and brain go through four significant stages of sleep that make up a full sleep cycle. Sleep cycles consist of both light and deep sleep stages, flowing in and out of one another seamlessly to make up a full night of sleep.

Understanding the difference between light and deep sleep can be helped if we understand the stages of sleep that a person goes through during the night.

  • Stage One: This lightest stage of sleep happens as you are falling asleep and then as you transition between other stages of sleep. This stage includes the rhythmic, alpha brain waves that are similar to what is found in the brain during wakefulness. It is easiest to be awoken during this stage of sleep, but it only accounts for about 3% of the total sleep you get in a night.
  • Stage Two: This second stage of sleep is still considered light sleep, but it is deeper than Stage One. This stage consists of about half of all of our sleep each night. It doesn’t happen all in one chunk, though. Instead, your body and brain are flowing in and out of this stage when moving into other phases. During the stage, sleep spindles occur when slow eye movements begin.
  • Stage Three: This is the deepest stage of sleep, when the slow, delta brain waves are prevalent. During this stage dreams do not occur, the heart rate slows down, breathing slows, and muscles relax to a state of barely moving. Your body is repairing and restoring itself during this important stage of sleep. Most adults spend about 20% of their overall night of sleep in this deep stage.
  • REM (Rapid Eye Movement) Sleep: This stage is considered to be the deepest sleep of all. It’s a very important phase of sleep in which your brain is very active, your body is almost paralyzed, and lot of dreaming happens. As the name suggests, the eyes often jerk back and forth very quickly during this stage of sleep. Researchers believe that your brain uses this time to regulate your emotions and memory. During this stage of sleep, your brain stops producing norepinephrine, which is the stress substance related to the amygdala, the fear portion of the brain. Some scientists believe that, because of this, REM sleep is critical for balancing out the emotions for the following day. This stage typically comprises 20%-25% of sleep for the normal, healthy adult.

In the past, researchers had sometimes divided deep sleep into two separate stages (3 and 4) but now they’ve combined them together into Stage Three, as their similarities were greater than their distinctions. Some resources may still refer to four stages of sleep in addition to REM sleep, but this is likely based on older information.

Light and Deep Sleep Patterns

As your brain and body move through the light and deep stages of sleep, a pattern of cycles forms. The brain and body go through approximately 4-5 cycles each night. One cycle usually looks something like this:

Stage 1 – Stage 2—Stage 3—Stage 2 – Stage 1 – REM Sleep

This cycle is then repeated throughout the night. At the beginning of the night, the REM sleep stage will be shorter, about 10 minutes or so. By the end of the night, your body and brain will spend more time in restorative REM sleep, which provides the brain with the tools it needs to function well the next day.

How to Get More Deep Sleep

Light sleep seems to happen automatically and the amount of light sleep a person gets doesn’t seem to matter all that much. On the other hand, a person’s life and health can be significantly altered if they aren’t getting enough deep sleep. Stage Three deep sleep restores and repairs the body, while REM deep sleep tends to restore and repair the brain.

Reduce Alcohol Intake

Although it might make you feel sleepy initially, drinking alcohol usually has a negative impact on a person’s ability to sleep very deeply at night. It typically will keep the brain in a bit of a twilight mode, without actually allowing it to pass over into Stage Three and REM deep sleep. Cutting out the alcohol in the evening should help to restore your ability to sleep at night.

Power Down

The lights that come from televisions, laptops, tablets, and smartphones are all capable of hijacking your sleep. Especially if you use them late into the evening. Those blue lights keep your brain active and prevent you from getting into the deep sleep that you need. Turn those devices off at least 1-2 hours before your bedtime to get the best results.

Keep a Regular Bedtime

Maintaining the body’s natural sleep/wake cycle is helpful in encouraging entry into deep sleep. Going to bed at the same time every night, and waking up at the same time each morning can be very helpful. Even on the weekends! Plus, if you can train your body and brain to wake up without an alarm clock, that’s even better.


Getting enough exercise early in the day, meditating, and doing other de-stressing activities can help your brain and body relax enough to get into deeper sleep during the night.

Plan for Eight Full Hours of Sleep Each Night

Since you get more of the deep REM sleep at the end of the night, cutting your sleep short by an hour can have an extremely negative impact on your mental and physical health. Planning to get a full 7-8 hours of sleep every night will ensure that you’re getting enough Stage Three deep sleep to restore your body in the beginning of the night, and then enough REM deep sleep to restore your brain towards the end of the night.


Getting enough light and deep sleep at night is critical to maintaining the optimal health of both your brain and your body. When you get enough of both light and deep sleep, your memory will improve, your emotions will stabilize, your body will feel better, and your overall quality of life will swing in the right direction.

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