The Importance of Getting Enough Sleep
Posted on 12.12.09 by Libby
by: Ali Wagoner
As college students who are habitually staying up late and constantly dozing off in class, a full night of sleep is incredibly important. Many people have their own theories on how much sleep they can get by on, some needing 8 hours to function the next day, some claiming they can work on only 4 hours of sleep. Whatever the case for you individually, it’s important to know what is going on during those hours when you’re asleep, and why it is critical for you to maintain a consistent sleep
schedule.
When you sleep, your brain does not remain in one constant “sleep state” throughout the night. Instead, your sleep may be divided into stages of Rapid Eye Movement (REM) and Non-REM (NREM) sleep. NREM sleep is further divided into 4 stages, each marking a different state in which your brain and body are in.
NREM sleep is most prevalent in the first part of the night, from right when you doze off until around four to six hours later.
Many people can relate to the feelings of Stage 1 sleep, which is the first part of the NREM cycle. This is when you’re drifting in and out of sleep, perhaps in your 9 A.M. class. You feel your head falling, and when you wake up suddenly it feels like you have been asleep for hours. You also may dream a little, but when awoken, will only remember a few fragmented images.
Stage 2 of NREM sleep accounts for 50% of your sleep cycle and is when your body goes into a “hibernation” state. Your body temperature drops, your breathing and heart rates even out, and your eye movements and brain waves become much slower. This is also the stage of sleep that you enter into when taking a nap.
Finally, what you may experience as “deep sleep” comes with Stages 3 and 4 of NREM sleep. Your bodily functions continue to slow and even out, including your blood pressure and muscle activity. These stages are essential for restoring your energy, keeping your immune system healthy and maintaining the homeostasis of your body (your hormones for example). This is the stage in which you will feel very groggy if awoken. You also may feel disoriented and depleted of energy if Stages 3 and 4 are interrupted. Although individuals may vary, this is probably the portion of NREM sleep that is important for you to sleep continually through in order to feel like “you got a good night of rest”.
Finally, nearing the end of your sleep, REM cycles start to appear. This stage accounts for approximately 20% of your sleep cycle and is noted by jerky eye movements and irregular and shallow breathing. If you’ve ever woken up before your roommate in the morning and looked at them sleeping, you may notice their jerky eye movements.
Also, during REM your limbs become temporarily paralyzed; if awoken during this stage some individuals will experience “sleep paralysis”, in which you are aware that you are awake, yet have trouble moving your body.
Similar to Stages 3 and 4 of NREM sleep, your REM cycles are critical for normal body functioning the following day. In general, the more REM cycles you get through (usually between 4-6), the better rested you will feel, and your brain can function at a higher level.
Other than the great feeling of surrendering to your pillow late at night, sleep truly does have biological advantages for your brain and body. Specifically, sleep improves your cognitive abilities by consolidating your memories. Here, consolidating may be broken down into stabilization and enhancement of memories. Stabilization means your memories become resistant to interference, and enhancement means sleep aids in restoring forgotten memories or producing additional learning without additional practice.
In a recent research project I conducted, I found that sleep is critically involved in the consolidation of memories, particularly memory for a central visually arousing object at the expense of its background. The study that I conducted showed that students who studied emotionally arousing scenes closer to when they went to sleep remembered the scenes with greater accuracy than students who had a greater delay time between studying and sleep. So does this mean that you should always study right before you go to bed? It is possible, just as long as your normal sleeping habits are not altered (like pulling an all-nighter).
Just as sleep has a direct benefit towards enhancing your memory, sleep deprivation has a direct link to reduced cognitive processes and even some affective disorders such as depression. When you stay up until 4 AM studying and then wake up three hours later, your important phases of non-REM sleep and longer phases of REM periods are missed.
One misconception that many people have is that they will sacrifice that one night to study, just as long as the following night they go to bed early. However, irregularities in your sleep schedule during just one night can negatively affect your sleep schedule the following night. Sleep deprivation can result in reduced attention span, slowed cognitive processing and errors, and reduced ability to multi-task. Furthermore, sleep deprivation accompanied by drinking alcohol will seriously affect your sleep cycle. Studies have shown that alcohol suppresses REM sleep, which is key for in creasing memory retention.
Disturbances of sleep belong to the main symptoms of depressed patients. Specifically, people who are depressed show a shortening of the interval between sleep onset and the occurrence of the first REM period. Also, they have an elongated amount of REM sleep, beyond what is considered to be typical in sleep cycles. These trends were proven by a study in 1997 in which more than 90% of depressed patients reported impairments in their quality of sleep. They also reported difficulties in falling asleep, frequent awakenings throughout the night, and early morning awakenings. Depression therefore, is thought of as one of the most common causes of insomnia.
Sleep well tonight. Your body will thank you.
