Among other things, sleep is characterized by lowered body movement and reduced reaction to the senses. Even so, our brains are constantly working, even when we sleep. Actually, when we sleep there are periods when our brain works harder than when we are awake, but the cerebral activity during sleep is different from that of our waking state.
The normal sleep rhythm is controlled by our inner clock which is regulated by the signalling substance melatonin which is produced in the pineal gland of the brain when it is dark. Another signalling substance - orexin - is also involved in our sleep rhythm. It is produced in the morning in an area of the brain called the hypothalamus and is responsible for waking us up. In the evening, the production of orexin is reduced and this makes us become sleepy and fall asleep. If the hypothalamus did not produce orexin, we would be constantly sleeping. People suffering from the disease narcolepsy have too few orexin-producing cells in their hypothalamus.
Regarding A and B personality types
Our genes decide whether we are A-people (early risers) or B-people (night owls). One can also be an A or B person to a greater or lesser degree. In extreme cases these people’s daily rhythms can be shifted up to 4 hours.
Type A Personality
A personality types are up and ready for the day by 5-7 in the morning, but have difficulty staying awake past 10 in the evening. The daily rhythm of A type personalities fits well into a normal work day.
Type B Personality
B personality types are not in any way “early risers.” They prefer to sleep until midmorning but are generally not fresh until midnight or later. Therefore B personality types have the greatest risk for shifting their day rhythm causing the development of sleep deprivation.
Sleep requirement
We spend about 1/3 of our life sleeping. Some people, however, seem to be able to do with significantly less; but common for all is that a good night's sleep is necessary to our mental and physical well-being. Studies of sleep seem to show that we need approx. 8 hours of sleep every night in order for us to function optimally. Even so, the amount of sleep which we require is individual. Some people function best on less than 8 hours of sleep and some people need more. Studies have also showed that people who are deprived of sleep for a period of time will develop psychoses.
Children need more sleep than adults in order to function normally. Therefore, children under the age of 5 should sleep at least 11 hours nightly. Children between the ages of 5 and 10 years should sleep at least 10 hours and children over 10 years old should sleep 9 hours nightly.
Sleep is divided into cycles of about 90 minutes, which each contain the phases of light sleep, deep sleep, and REM sleep. REM sleep is the one in which we dream. REM sleep is believed to be important to our sexual and mental well-being. During deep sleep our body produces several important hormones, e.g. growth hormone which is highly significant to both our physical and psychological well-being. In small children, the REM stage comprises half of the sleep cycle. The sleep of young individuals consists of 25% light sleep, 25% REM sleep, and 50% deep sleep. The proportion of deep sleep is reduced with age just as is the total need for sleep. When elderly individuals complain of not being able to sleep this might be related to the reduced need for sleep.
The elderly and sleep
When some older people, in this case meaning over 45 years of age, complain about not being able to sleep, it could be because their need for sleep has been reduced. This can sometimes be due to lowered hormone production. For example, lowered thyroid activity, lowered levels of the male sex hormone testosterone, and a low level of the growth hormone IGF-1 can lead to shortened nightly sleep because of trouble sleeping.
Sleep and alcohol
Even though alcohol makes it easier to fall asleep, alcohol in the blood ruins sleep quality. It increases the pulse it decreases or eliminates the percent of REM sleep in the sleep cycle. It is believed that it only takes 5 – 6 units of alcohol to ruin the quality of sleep.
The following are some variants of sleeping disorders:
Sleep disorders in general
Studies of sleep have suggested that we are inclined to believe that we get less sleep than we actually do. When you cannot fall asleep, the reason will most often be that you are not tired enough. Stress, worries, and depression can also result in trouble falling asleep, and stress seems to be able to reduce the proportion of deep sleep.
Just as in any other aspect of life, your lifestyle is important to the quality of sleep. A good night's sleep is inseparably bound up with good nutrition, exercise, a normal weight, and mental well-being.
Besides its beneficial effect on the heart, circulation, overweight, and immune defence, daily exercise seems to be able to increase the so-called alpha waves in the brain that appear when you are at ease and relaxed. Exercise is extraordinarily beneficial in case of sleeping problems.
Research also indicates that men and women have more disturbed sleep when they sleep together than when they sleep alone. Men’s quality of sleep is reduced more than that of women by sleeping together, maybe because women sleep deeper than men.
Sleep and mobile phones
Radiation from turned on mobiles is suspected of stressing the brain which causes the ability of achieving the deep sleep phases to be compromised and reduces the percent of deep sleep in the sleep cycle.
Difficulties falling asleep
Difficulties falling asleep can be caused by over stimulation from stimulating substances like ephedrine, coffee, black tea, coke, or guarana. In addition, noise, pain, stress, rambling thoughts, worries, depression, and anxiety can prevent you falling asleep.
Difficulties in sleeping through the night
Not being able to get a long, continuous sleep. Too early awakening and a generally poor quality of sleep can be the result of depression and anxiety. However, you should always be aware of more simple causes, like an uncomfortable bed, for example.
Snoring
Snoring can both disturb your sleep and the sleep of others. The reason that it can disturb your own sleep is that breathing while snoring can become very irregular. Snoring can be caused by some special anatomical irregularities, but most often occurs when the lingual musculature relaxes and falls back into the throat when sleeping. At the same time, the relaxed muscles of the head will cause the soft palate and the uvula to be enlarged. Thereby, the respiratory passages are reduced and the throat, palate, and uvula will start vibrating in synch with the breathing of the sleeping person. The disposition for snoring is increased when using sleeping pills or being under the influence because the musculature in this case is relaxed even further. Being exposed to tobacco smoke can also result in snoring.
Snoring is also increased if you have dry mucous membranes, if you are overweight, if you have a large uvula or tongue, or if you suffer from adenoids, enlarged tonsils, or a small lower jaw. Women generally snore less than men; however, the disposition to snoring (and the volume) is increased with age in both sexes.
Sleep apnoea
Sleep apnoea means a temporary suspension of breathing occurring repeatedly during sleep. Contrary to snoring, this phenomenon can severely disturb the affected person's sleep. In sleep apnoea, the person stops breathing for a minimum of 10 seconds at a time and this can happen up to several hundred times every night.
The same mechanism is responsible for sleep apnoea as for snoring, but in apnoea, the respiratory passages are completely closed or breathing is severely compromised and therefore almost no air can pass down into the lungs. The oxygen content of the blood becomes be too low while the blood level of carbon dioxide becomes too high. The accompanying choking sensation causes the person to jerk awake and feel greatly uneasy but after the breathing has normalized the person usually falls asleep again and the whole cycle is repeated shortly after.
In the morning, the person cannot remember what has happened during the night but feels extremely tired, unfocused, and edgy all day. Socially, this can destroy marriages and careers and result in road accidents as the person becomes increasingly "zombified" by the lack of a good night's sleep.
When the body receives too little oxygen, it can lead to the so-called metabolic syndrome. This is where the body cannot metabolise fat and sugar effectively. This causes and increased risk of elevated blood pressure, headache, and cardiovascular disease in people with sleep apnoea.
Sleep apnoea often affects overweight, middle aged men whose airways are stressed by the pressure of their weight.
Almost 40% of those suffering from sleep apnoea have suffered from speech problems - e.g. stuttering - as children. This has given rise to the theory that the suffering can possibly be connected to an early subtle brain damage of the area where the speech centre is located and that this will develop into sleep apnoea many years later.
Snoring and sleep apnoea is normally reduced when sleeping on your side.
As mentioned above, our mental well-being and the quality of our sleep are intertwined. If you take sleeping medicine, the duration of the deep sleep is reduced and the REM sleep which is important to our mental well-being is disturbed. Moreover, sleeping medicine is habit-forming and has a tendency to losing its soporific effect after prolonged use.
Dreams
In some cases, nightmares and poor quality of sleep can be connected to a lack of B-vitamins; particularly vitamin B1 and -B6, but also the minerals calcium, magnesium, and zinc.
Difficulties remembering your dreams is not necessarily an expression of poor quality of sleep; quite the contrary. Incidentally, this is most common in men. Men remember dreams better if they have had sex. Women remember their dreams better if they sleep alone.
