The Importance of Rest and Sleep in Staying Healthy

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Why do people need rest and sleep? Many of us might prefer to spend our 24 hours each day in a more "constructive" activity than sleep, but the fact remains that our bodies are tied to internal cycles, rhythms that dictate our need for periodic rest. And all of us have experienced the exhausted and drained feeling at the end of a busy day when we know intuitively that it is time to "recharge our batteries" by going to sleep. After an interval of sleep, we wake up and feel refreshed and are once again ready to meet the day’s challenges.

Functions of Sleep

Adequate sleep is essential for good physical and mental health. In recent sleep studies, it was shown that approximately one third of 50 normal young adults, surveyed randomly, were chronically sleep deprived. In this study, chronic sleep deprivation was defined as sleeping less than 6.5 hours per night on week nights, when they actually needed to sleep approximately 8.5 hours per night. Dr. Frist Sr. thinks that eight hours of sleep per night is adequate for most people, adding that "with increased age, you may get too little or too much sleep."

Sleep is felt to be a necessity for the body’s restorative processes. These processes occur in harmony with the body’s sleep cycles dictated by the body’s natural rhythms. These cycles change into slightly more than 24 hours in length and are reset each day by light and other time cues.

A striking effect of disrupted body rhythms is felt with "jet lag" when movement to a new destination in another time zone produces physical symptoms as the traveler tries to adjust to the new time. Fatigue, headache, irritability, lightheadedness and hunger are some of the troublesome symptoms. Important risk factors that make one more susceptible to jet lag include (1) eastward travel, (2) number of time zones crossed, (3) sleep lost before and during travel, (4) caffeine or alcohol (which disrupt sleep) and (5) increased age.

Prevention and treatment of "jet lag" have focused on restabilizing the internal clock by diet, light exposure and possibly the use of the hormone melatonin. Darkness stimulates melatonin release resulting in its peak level at night. Conversely, light inhibits its release. Travelers going from the U.S. to Europe can be advised to seek several hours of bright light late in the morning of arrival and consider small doses of melatonin each evening after arrival, for three to seven days.

Effects of Sleep Deprivation

Sleep cycles affect many bodily processes including cell division, protein synthesis, immune function, mood and task performance. Sleep deprivation has been shown to adversely affect all of these processes, making people more susceptible to illness and slower to recuperate. There have been a flurry of studies regarding sleep deprivation of patients in intensive care units and their degree of illness, complications and length of ICU stay. Although these studies are preliminary, it is generally believed that patients do better when sleep/wake cycles are preserved.

Sleep loss and deprivation are common occurrences in our society. And sleep disorders increase with age. One-fourth of a random sample of 65 year olds had a condition, sleep apnea, or interruptions in breathing while asleep. Almost one-half of this same group reported periodic involuntary leg movements when attempting to sleep.

As a society, chronic sleep deprivation is an expensive and often deadly dilemma that annually causes destruction of human life and property. In a group of train drivers surveyed, 70% reported "dozing off while driving a train." And for fatal car accidents, the three most common causes as reported by traffic safety committees are alcohol (18%), poor attention (15%) and sleepiness (10%). And all three of these conditions can influence each other. In a recent year, there were 4,800 fatal accidents involving truck drives with each fatal crash costing approximately 3 million dollars. A recent study estimates that sleep-related accidents in our country cost from 2 to 56 billion dollars annually.

Data indicate that decreased alertness develops after one sleep period of six hours. People working "graveyard" shifts commonly sleep an average of 5.8 to 6.4 hours per day. Rotating shift workers sleep even less, sleeping only 5.25 to 5.5 hours per day when working at night.

Do you need the average night’s sleep of approximately eight hours? The best way to determine this is by going to bed in the evening when sleepy and waking up in the morning without an alarm and noting the total time slept.

Chronic sleep deprivation has been the cause of increased daytime sleepiness, and also impaired performance and mood throughout the day. Various symptoms of illness occur with continued sleep deprivation. These symptoms include progressive deterioration of mental functioning, weariness and a tendency to withdraw from the outside world. People who are sleep deprived make few unnecessary movements and become confused more easily. As sleep deprivation continues, certain bodily sensations begin to develop. Many people develop a tightness around the head, their eyes begin to burn and itch and vision becomes blurred. After 30 to 60 hours of sleeplessness, people have difficulty with depth perception. They see halos around lights. After 90 hours of sleeplessness, some people develop vivid visual and tactile hallucinations, their sense of reality becomes confused and their time sense is distorted. If sleep loss is continued beyond 100 to 200 hours, symptoms intensify and resemble psychosis. Fortunately, people who are sleep deprived usually recover from the abnormal symptoms after sleeping for a period of time.

Not only are major sleep disturbances, such as intensive care stays, draining to the body’s natural healing mechanisms, but many seemingly benign factors can also disrupt the natural rhythms of sleep. Fever, pain, anxiety, depression, sleep apnea and cardiopulmonary diseases all adversely affect sleep. Many medications also have undesirable affects, such as the commonly used benzodiazepines (Valium, Xanax, Librium, Ativan, etc.). These hypnotics may produce a rebound insomnia or interfere with daytime functioning caused by cumulative build-up of the active metabolites. Alcohol is commonly believed to induce relaxation and sleep. However, it causes a disrupted sleep pattern that robs the body of the refreshing quality of sleep.

Insomnia has long plagued modern society and affects millions yearly. Good "sleep habits" are important to everyone. A cool, quiet sleep place, maintaining a regular bedtime, avoidance of alcohol, caffeine and strenuous exercise within four to six hours prior to sleep, removal of a restless bed partner and, if needed, "white noise" (artificial sounds of wind, rain, the ocean, etc.) are all useful for good sleep hygiene and the nurturing of overall health and well-being.

Normal Sleep and Dreaming

While sleeping approximately eight hours per night is vital to people’s physical and mental health, dreaming is necessary for people’s psychological health. Most theories of dream function state that dreams enable people to master their environments. In dreams, people integrate new experiences and solve conflicts from their waking lives. Artists and inventors have obtained some of their most important creative ideas when dreaming. Niels Bohr, the Danish physicist, first derived the model of an atom that was the basis for atomic physics, from a dream! Another function of sleep and dreaming is that both assist in the processing and storage of memories.

What is normal sleep? Normal sleep is generally divided into two categories- REM (rapid-eye movement) and Non-REM sleep. Non-REM sleep is further subdivided into stages one through four. Stage four sleep has been increasingly recognized as very important in maintaining overall well-being. The lack of stage four sleep appears to be associated with a cluster of symptoms that includecreased awareness, muscle aches and fatigue and is referred to as fibromyalgia.

REM sleep follows non-REM sleep approximately 70 to 90 minutes after sleep onset and a cycle of NREM/REM sleep repeats itself four to five times throughout the night. Dreaming appears to be associated with REM sleep and is considered essential for the rejuvenating quality of sleep.

Sleep and rest allow the body to replenish depleted energy reserves and allow us to maintain normal physical and mental functioning. Benjamin Franklin said it best in Poor Richard’s Almanac in 1735, "Early to bed and early to rise, makes a man healthy, wealthy and wise."

by Marilynn Michaud, M.D. and Audrey Silver, R.N.C.

Editor’s Note: Marilynn Michaud, M.D. is an internist associated with Columbia Centennial Medical Center in Nashville, Tennnessee.


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