Sleep is defined as a state of unconsciousness from which a person can be aroused. In this state, the brain is relatively more responsive to internal stimuli than external stimuli. Sleep should be distinguished from coma. Coma is an unconscious state from which a person cannot be aroused. Sleep is essential for the normal, healthy functioning of the human body. It is a complicated physiological phenomenon that scientists do not fully understand.
We hear many an instance, rather may have observed it ourselves, that sometimes we do not wake up refreshed. Many of us would want to sleep for some more time. Why do such situations arise?
The answer is simple: it means that we haven’t slept well the previous night. Many reasons could be there which played havoc in our night’s sleep. There are infinite explanations to this so called sleep, medically, psychologically, hypnotically, subconsciously & many more.
Every human being has the major basic functions in common. One of these vital necessities is the need to sleep. Though we all have different sleep patterns, sleep different amounts, and the quality of our slumber varies greatly, sleep is literally necessary to stay alive. Strangely, though it is just as important as breathing, many people live with agonizing and life altering sleep disorders. The importance of sleep is often overlooked. Our body needs sleep for many good reasons. We feel refreshed as our body mechanisms get rejuvenated after a good sleep. During a good nap, we lower the energy levels expelled daily, our muscles and soft tissues are repaired and revitalized, and our mind is able to process memories and things we have learned for the day. Although one day of sleep deprivation is not fatal, it will indeed cause alterations in mood, physical well being, and overall brain functions. If we keep neglecting sleep, we will only land up into serious & grave sleep-deprived associated symptoms like poor mental clarity, hallucinations (where the person imagines unrealistic things- a sense of perception that has no basis to external).
Studies have shown that majority of fatal car crashes are directly correlative to lack of sleep. According to the National Sleep Foundation “If you have trouble keeping your eyes focused, if you can’t stop yawning, or if you can’t remember driving the last few miles, you are probably too drowsy to drive safely.” It is important to know that caffeine and other stimulants cannot overcome the effects of severe sleep deprivation. Therefore, if you find yourself driving in a sleep-deprived state, it is imperative that you find a safe place to stop and catch up on your sleep before continuing safely on your way.
Stages of Sleep
sleep is a dynamic process. There are 2 distinct states that alternate in cycles and reflect differing levels of neuronal activity. Each state is characterized by a different type of brain wave (electrical activity that is recorded with the help of electrodes placed on the skull) activity. Sleep consists of non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. NREM is further subdivided into the following 4 stages:
Stage I (light sleep)
Stage II
Stage III & IV (deep sleep)
The stages of NREM sleep and REM sleep cycles, over and over again during a night's sleep. Stages I, II, III, and IV are followed by REM sleep. A complete sleep cycle, from the beginning of stage I to the end of REM sleep, usually takes about one and a half hours.
For the purpose of analysis, a night’s sleep is divided into 3 equal time periods: sleep in the first third of the night, which comprises the highest percentage of NREM; sleep in the middle third of the night; and sleep in the last third of the night, the majority of which is REM. Awakening after a full night’s sleep is usually from REM sleep.
NREM Sleep
Stage I is a stage of light sleep and is considered a transition between wakefulness and sleep. During this stage, the muscles begin to relax. It occurs upon falling asleep and during brief arousal periods within sleep, and usually accounts for 5-10% of total sleep time. An individual can be easily awakened during this stage.
Stage II occurs throughout the sleep period and represents 40-50% of the total sleep time. During stage II, brain waves slow down with occasional bursts of rapid waves. Eye movement stops during this stage.
In stage III, extremely slow brain waves called delta waves begin to appear. They are interspersed with smaller, faster waves. In stage IV, delta waves are the primary waves recorded from the brain. These 2 stages are distinguished from each other only by the percentage of delta activity. Together they represent up to 20% of total sleep time. Stages III and IV are called deep sleep, during which all eye and muscle movement ceases. It is difficult to wake up someone during these 2 stages. If someone is awakened during deep sleep, he does not adjust immediately and often feels groggy and disoriented for several minutes after waking up. Some children experience bedwetting, night terrors, or sleepwalking during deep sleep.
REM Sleep
REM sleep represents 20-25% of the total sleep time. REM sleep follows NREM sleep and occurs 4-5 times during a normal 8- to 9-hour sleep period. The first REM period of the night may be less than 10 minutes in duration, while the last may exceed 60 minutes. In a normal night’s sleep, bouts of REM occur every 90 minutes.
When the person is extremely sleepy, the duration of each bout of REM sleep is very short or it may even be absent. REM sleep is usually associated with dreaming. During REM sleep, the eyeballs move rapidly, the heart rate and breathing become rapid and irregular, and the blood pressure rises. The muscles of the body are virtually paralyzed. The brain is highly active during REM sleep, and the overall brain metabolism may be increased by as much as 20%. The electrical activity recorded in the brain during REM sleep is similar to that which is recorded during wakefulness.
Infants have an overall greater total sleep time than any other age group. Their sleep time can be divided into multiple periods. In newborns, the total sleep duration in a day can be 14-16 hours. Over the first several months of life, sleep time decreases; by age 5-6 months, sleep consolidates into an overnight period with at least 1 nap during the day. In adults, sleep of 8-8.4 hours is considered fully restorative. In some cultures, total sleep is often divided into an overnight sleep period of 6-7 hours and a nap of 1-2 hours.
Some people may need as little as 5 hours or as much as 10 hours of sleep every day. The period of time a person sleeps depends also on the fact whether he or she has been deprived of sleep in previous days. Sleeping too little creates a "sleep debt." This debt needs to be adjusted by sleeping for longer periods over the next few days. People tend to sleep more lightly and for shorter periods as they get older. Biological variations that occur in the course of 24 hours are called circadian rhythms. Circadian rhythms are controlled by the body’s biological clock. Many bodily functions follow the biologic clock, but sleep and wakefulness comprise the most important circadian rhythm. When we cross time zones, our circadian rhythms get disrupted leading to jet lag. It usually takes several days for our body rhythms to adjust to the new time.
Body temperature cycles are also under control of the hypothalamus. An increase in body temperature is seen during the course of the day and a decrease is observed during the night. The temperature peaks and troughs are thought to mirror the sleep rhythm. People working in shifts have an increased risk of heart, gastrointestinal, emotional, and mental problems. In order to evaluate and truly respect the importance of sleep, it is relevant to consider the symptoms that occur with the absence of proper sleep. First of all, the average duration of sleep should be around eight hours. Studies have shown that certain individuals are able to function with less sleep, with as little as six hours; however others are unable to function unless they have reached as many as ten hours of rest. Contrary to the common tendency of many to try to “sneak in extra Z’s” by hitting the snooze button over and over, this habit usually hinders the body’s collective sleep and reduces the time spent in REM (rapid eye movement). Burn outs do occur, if sleep deprivation continues to persist. Please do not ignore your sleep, coz once you land up in a burnout, it takes a long time to come back. May be on weekends or on a relaxed day, you could take a long long nap.
There are some simple tips to follow on your own if you are seeking a healthier sleep pattern.
Eliminate caffeine in the afternoon and evening. The consumption of caffeine within a few hours before bed will directly halt your ability to fall asleep. Exercise, heavy meals, or drugs/alcohol will also diminish the quality of sleep if occurring shortly before hitting the hay. Instead, exercising earlier in the day will aid in ascertaining a healthy sleep regimen. Establish a routine. This will help balance the body’s internal clock and ultimately inadvertently initiate the readiness and acceptance of sleep. Make sure your bed is comfortable and your environment is appropriate. Studies acknowledge that noise, light, even a partner with sleeping troubles will easily influence the quality of sleep. Be aware of your nightly surroundings and make sure they are not interfering in achieving a healthy sleep pattern. There are many alternatives to try before depending on sleeping pills. In fact, many sleeping pills have adverse side effects, including trouble sleeping! Those who work in night shift, and often sleep during the day, please make your room dark enough like a dummy of the darkness of the night, so that your body can get the feel of the night although its day. This is very important failing which various unending problems crop up.
Do realize the importance of healthy sleeping habits & spread the word to friends and families.
- ONE MAN CAN MAKE A DIFFERENCE-
Edmond Fernandes
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