By Joanne P. Shelby-Klein BSN RN

Sleep, some of us think we don’t get enough, some wonder why we need it at all and most wonder what it is. We all know when someone is sleeping but do we know what is happening when they sleep and we ask the question why is sleep important? Back in 1953, sleep was defined as a stoppage of most brain activity with the brain being passive. Ongoing research has shown that when people are awake the brain neurons are at their most active. However, when people are asleep the brain neurons remain active in a variety of ways. Research is just beginning to show us how sleep affects us both physically and mentally.

HOW DOES SLEEP WORK?

Whether a person is awake or asleep is controlled by chemical signals carried by neuro-transmitters to the brain and different groups of nerves, called neurons. Two of the chemical signals are serotonin and norepinephrine. These chemicals tell the neurons located in the brainstem to keep some of the brain cells active when we are awake. When we are asleep different neurons at the base of the brain turn on and begin sending signals while the neurons that keep us awake switch the signals off. When we wake up, the process reverses. There are 5 different phases that we pass through during sleep. Stages 1, 2, 3, 4 and Rapid Eye Movement or REM sleep.

• STAGE 1: sleep: Also known as “light sleep”. During this stage our muscle activity slows and our eyes move rapidly. During this stage we tend to drift in and out of sleep and can be easily awakened.
• STAGE 2: During this stage, our brain waves (electrical impulses that can be picked up by electrodes) become slower and our eye movements stop. During this cycle, the brain waves may have short bursts of activity called sleep spindles. Also, your heart rate slows down, muscles alternate between relaxing and contracting and the body temperature drops in preparation for deep sleep.
• STAGE 3: In this stage, extremely slow brain waves are noticed and mix in occasionally with shorter faster waves. It is difficult waken someone up during this stage.
• STAGE 4: This is known as deep sleep. The extremely slow brain waves are more noticeable here. It is also difficult to wake someone up during this stage. There is no muscle or eye activity during this stage. If awakened during this stage, you will feel groggy, disoriented and need a few minutes to become fully awake. During this stage children may bed wet, night terrors may be experienced and some people may sleepwalk.
• REM SLEEP: As we move into this stage, eye movements become very quick and jerky. Breathing becomes very rapid, shallow and irregular, Arm and leg muscles also become paralyzed for a short period of time. If you wake up during this stage, you may experience and remember dreams.

These 5 stages make up one cycle of sleep. 50% of sleep time is spent in Stage 2 sleep with 20% spent in REM sleep. The other 30% is divided between Stages 1, 3, 4. A complete sleep cycle takes from 90 to 110 minutes. For example if you sleep 8 hours per night you would have between 4.4 and 5.3 cycles per night. If you sleep 7 hours you would have between 3.8 and 4.7 sleep cycles. The number of cycles vary depending on whether the each cycle is 90 or 110 minutes long.

WHY DO WE NEED SLEEP?

The reasons we need sleep remains a mystery and is still being researched. One theory is that the reduced brain activity during sleep gives the brain cells a chance to make any needed repairs and develop properly. Another theory is that interrupting the chemical neurotransmitter signals during sleep allows the chemicals to become re-sensitized and better able to regulate mood and learning. Even with these theory’s sleeps necessity is still a mystery.

WHAT HAPPENS IF WE DON’T GET ENOUGH SLEEP?

Getting the proper amount of sleep is important for all of us to be able to work well when we are awake. A lack of sleep can lead to feeling drowsy and having trouble concentrating. People report having problems with memory, as well as trouble with physical activities. People who go without enough sleep for a long period of time may develop mood swings and even hallucinate. People who have poor sleep patterns or lack sleep on an ongoing basis may be at risk for depression and suicide, work related injuries from clumsiness or poor concentration.

HOW DOES THE BODY KNOW WHEN IT’S TIME TO GO TO SLEEP AND WAKE-UP?

All of our bodies operate on a natural internal body clock known as the Circadian rhythm. It is also known as the sleep/wakefulness cycle, a built in system that tells the body when it’s time to go to sleep and when to wake up. For most people, this internal clock is controlled by when it is light and when it is dark. Your body responds to your circadian rhythm by having up and down periods of wakefulness and sleepiness. For example, most people feel sleepy between 2am and 4am and again between 1pm and 3pm. Our circadian rhythm can change over time. For example, children and teenagers circadian rhythms can send signals to sleep longer as well as go to bed and get up earlier or later. The body’s circadian rhythm can also be changed when you sleep in one day, go to bed later than normal or have to work different shifts.

WHAT HAPPENS IF THE CIRCADIUM RHYTHM IS CHANGED FOR A LONG PERIOD OF TIME?

If the circadian rhythm is changed for a long period of time and good sleep is interrupted for a long period of time a condition known as sleep deprivation can occur. People who work shifts that are different than their normal circadian rhythm are at risk for having poor sleep patterns, especially if they rotate from one shift to another in a short period of time.

Long term sleep deprivation and poor sleep patterns can lead to serious medical problems.

• Metabolic syndrome, a series of diseases that can lead to an increased risk for heart disease, diabetes and strokes.
• Obesity
• Heart Disease.
• Depression
• Cancer
• Alzheimer’s
• Parkinson’s Disease
• Sleep Disorders

WHAT CAUSES SLEEP DEPRIVATION?

There are two types of sleep deprivation, acute and chronic. Acute sleep deprivation happens when sleep is disturbed for two days. This is usually caused by illness, everyday life stresses or drastic changes in temperature. It also resolves when the stressful situation resolves. Chronic Sleep Deprivation is a long term change in sleep habits or ongoing loss of sleep. This is usually caused by depression, chronic stressful situations, or chronic pain/discomfort at night.

WHAT ARE SOME OTHER SLEEP DISORDERS TO BE CONCERNED WITH?

• Insomnia is when a person has a hard time falling asleep or staying asleep. It can usually be treated with medications and a change in sleep habits.
• Excessive Daytime Sleepiness (EDS) or Narcolepsy. This is when a person falls asleep during what would be normal waking hours. Sometimes it happens when a person stops an activity to relax for few moments and they fall asleep. EDS is considered a symptom and not a disorder in itself.
• Somnambulism. This is when a person sits up, walks or does other activities while asleep and does not remember doing any of the activities.
• Sleep Terrors. This happens when people suddenly scream, flail their limbs, feel frighten and are difficult to awaken. This is very common in children and may be accompanied by nightmares.
• Sleep Apnea. This happens when sleep is interrupted because breathing stops for a brief period of time. When it restarts a loud snort or snoring occurs. When the snoring occurs sleep is interrupted, even though the person may not realize that they have awakened for a brief time. Everyone may have isolated episodes of snoring. If snoring persists it is important to talk to a health care provider to determine why snoring is happening.

WHAT CAN I DO TO IMPROVE MY SLEEP HABITS AND GET BETTER SLEEP?

Getting a better quality of sleep can be as simple as making a few lifestyle and habit changes. The National Sleep Foundation recommends:

• Finding a sleep schedule that works for you and stick with it, even on the weekends. By going to bed and getting up at a regular time every day, your bodies circadian rhythm will get into a routine and help you know when it is time to go to sleep and help you sleep all night.
• Creating a relaxing sleep environment by keeping the bedroom dark and quiet. It can also be helpful to use your bedroom for sleeping only, not for watching television, eating or using the computer. Removing electronic gadgets, except for alarm clocks may be helpful.
• A relaxing bedtime ritual may be helpful, especially if done away from computers, bright lights and other stressful activities. Some examples of bedtime rituals are meditating, taking a warm bath.
• Avoid napping in the afternoon. Power naps and cat naps may give you a short term benefit; however, it can also interrupt the ability to fall asleep at your regular time.
• Daily exercise can help you get a better night’s sleep. Any type of exercise, even light stretching can help. Try to avoid exercising right before going to bed however.
• Keep the bedroom cool, between 60 and 67 degrees is ideal.
• Sleep on a comfortable and supportive mattress. Most good quality mattresses work well for 9 to 10 years. Use a pillow or pillows that are comfortable for you and are free of any potential allergens.
• Manage your natural circadian rhythm with the use of bright light. Try to avoid bright lights at night and spend time in bright sunlight or lamps in the morning.
• Try to avoid caffeine, alcohol, cigarettes and heavy meals for 2-3 hours before going to bed. Alcohol, caffeine and cigarettes can act as a stimulant to keep the body from settling into a good sleep. Heavy meals or snacks with spicy foods can cause indigestion that can disrupt sleep. If you are hungry at night, eat a light snack only preferably 45 minutes before going to bed.
• Use the last hour before going to bed as a time to wind down and relax. It can be helpful to not use electronics such as computers during that last hour before bed. Electronic devices give off a light that can cause the brain to become active.

WHAT SHOULD I DO IF I CAN’T FALL ASLEEP OR WAKE UP AND CAN’T GO BACK TO SLEEP?

Most people fall asleep 15 to 20 minutes after lying down in bed. If you find yourself awake after 20 minutes, get up out of bed and go to another room to read a book (not electronic) or listen to relaxing music until you begin to feel sleepy then go back to bed. Try and think positive relaxing thoughts before going back to bed. If it becomes an ongoing problem, contact a health care provider to discuss what may be causing you to have difficulty going to sleep or staying asleep.

HOW CAN I SLEEP BETTER WHEN I WORK THE NIGHT SHIFT OR ROTATE SHIFTS?

Over 20 million Americans work on the night shift or rotate shifts. This can lead to their sleep patterns and circadian rhythm being disrupted on a regular basis. Here are a few tips to improve sleep in that situation:

• Wear sunglasses on the way home from work in the morning to decrease the amount of sunlight exposure reaching your eyes and signaling the brain it’s time to wake up.
• Once at home, go directly to bed to sleep.
• Approximately 4 hours before the end of your work shift, stop caffeine intake. It takes that long for caffeine to be removed from your system.
• Let people know that you work the night shift and are not available for phone calls, emails etc. Turn the phone ringer off so all calls go to voicemail.
• Use blackout curtains or a sleep mask to help the bedroom be dark enough for good sleep.
• Schedule appointments around your sleep hours.
• Eat regular meals during the hours you are awake.

Sleep is important to all of us to keep our bodies working properly. For the average adult 7 hours of sleep per night is enough. If you are having trouble sleeping, it is important to talk to your healthcare provider about your sleep habits, general health and if sleeping aids will be necessary.

REFERENCES

1. Strohl, KP. MD (2015, May) Introduction to Sleep Apnea. Merck Manual Professional edition. Retrieved from URL: https://www.merckmanuals.com/professional/pulmonary-disorders/sleep-apnea/introduction-to-sleep-apnea
2. Alhol, P. Pola-Kantola, P. (2007, October). Sleep Deprivation: Impact on Cognitive Performance. Neuropsychiatric Disease Treatment. Volume 3:5: pps 553-567
3. Takahashi, M. (2012, March). Prioritizing Sleep for Healthy Work Schedules. Journal of Physiological Anthropology. 31:6. http://www.jphysiolanthropol.com/content/31/1/6
4. Siegel, JM. (2003, November). Why We Sleep. Scientific American. Pps 92-97. http://www.semel.ucla.edu/sites/all/files/sciamsleep.pdf
5. Cirelli, C. Tononi, G. (2008, August) Is Sleep Essential? Plos Biology. Vol 6 (8): e 216 http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.0060216
6. NIH. NINDS. Brain Basics, Understanding Sleep. Retrieved from URL: http://www.ninds.nih.gov/disorders/brain_basics/understanding_sleep.htm
7. Vance, DE. Heaton, K. Eaves, Y. Fazeli, PL.(011, October) Sleep and Cognition On EveryDay Functioning In Older Adults: Implications for Nursing Practice and Research. Journal of Neuroscience Nursing. Volume 43 No. 5. P 261-271.
8. National Sleep Foundation. Retrieved from URL: https://sleep.org/articles/sleep-cycles-everything-you-need-to-know/
9. Dijk D-J, Archer SN (2009) Light, Sleep, and Circadian Rhythms: Together Again. PLoS Biol 7(6): e1000145. doi:10.1371/journal.pbio.1000145
10. National Sleep Foundation. What To Do When You Can’t Sleep. Retrieved from URL: http://sleepfoundation.org/insomnia/content/what-do-when-you-cant-sleep
11. Brain and Spine Team. (2014, December). How You Can Sleep Better if You Work the Night Shift? Cleveland Clinic Health Hub. Retrieved from URL: http://health.clevelandclinic.org/2014/12/how-you-can-sleep-better-if-you-work-the-night-shift/
12. UCLA Sleep Disorders Center. Coping with Shift Work. Retrieved from URL: http://sleepcenter.ucla.edu/body.cfm?id=54