Sleep-walking Health Dictionary

Sleep is a state which alternates with wakefulness, and in which awareness and responsiveness to the environment are reduced. It is not, however, uniform and can be divided into two main states di?erentiated according to electrical recordings of brain activity (EEG), of the muscles (EMG), and of the eye movements (EOG).

Non-rapid-eye-movement (NREM) sleep This is subdivided into four stages, of which stage 1 is the lightest and stage 4 the deepest. The activity of the cerebral cortex (see BRAIN) is diminished and the body’s functions are mainly regulated by brain-stem activity. The metabolic rate is reduced; in keeping with this the temperature falls, respiration is reduced, cardiac output, heart rate, and blood pressure fall, and activity of the sympathetic nervous system is reduced. NREM sleep normally occurs at the onset of sleep except in neonates. During adult life, the duration – particularly of stages 3 and 4 – of NREM sleep becomes less, and very little of this deep sleep occurs after the age of 60 years.

NREM sleep has been thought to have several functions, such as energy conservation and growth. Growth hormone is produced in bursts during stages 3 and 4, and more cell division occurs during this type of sleep than during wakefulness. A controversial proposal has been that processing of information acquired during wakefulness occurs during NREM sleep.... sleep

The sensation of being unable to move at the moment of going to sleep or when waking up, usually lasting only a few seconds. It may be accompanied by hallucinations. Sleep paralysis most often occurs in people with narcolepsy. (See also cataplexy.)... sleep paralysis

A disorder in which there are episodes of temporary cessation of breathing (lasting 10 seconds or longer) during sleep.

People with sleep apnoea may not be aware of any problem during the night, but they may be sleepy during the day, with poor memory and concentration. Severe sleep apnoea is potentially serious and may lead to hypertension, heart failure, myocardial infarction, or stroke.

Obstructive sleep apnoea is the most common type and may affect anyone, but more often middle-aged men, especially those who are overweight. The most common cause is over-relaxation of the muscles of the soft palate in the pharynx, which obstructs the passage of air. Obstruction may also be caused by enlarged tonsils or adenoids. The obstruction causes snoring. If complete blockage occurs, breathing stops. This triggers the brain to restart breathing, and the person may gasp and wake briefly.

In central sleep apnoea, breathing stops because the chest and diaphragm muscles temporarily cease to work, probably due to a disturbance in the brain’s control of breathing. Causes include paralysis of the diaphragm and disorders of the brainstem. Snoring is not a main feature.People who are overweight may find losing weight helps.

Alcohol and sleeping drugs aggravate sleep apnoea.

In one treatment, air from a compressor is forced into the airway via a mask worn over the nose.

Night-time artificial ventilation may be needed.

Tonsillectomy, adenoidectomy, or surgery to shorten or stiffen the soft palate may be performed.... sleep apnoea

This is characterised by the presence of rapid eye movements and a reduction in muscle tone. Cerebral cortical activity is prominent and its blood ?ow increased. This activity is, however, di?erent from wakefulness and may cause irregular movements of the body as well as of the eyes. Most dreams occur in REM sleep: these may represent a process of reorganising mental associations after the period of wakefulness. The analysis of the content of dreams has been subject to a variety of interpretations, but no consensus view has evolved.

Physiological changes, such as a fall in temperature and blood pressure, take place just before sleep and continue during the early stages of NREM sleep. There is an intrinsic rhythm of sleep which in most subjects has a periodicity of around 25 hours. This can be modi?ed by external factors to bring it into line with the 24-hour day. Two peaks of a tendency to sleep have been identi?ed, and these usually occur between around 14.00–18.00 hours, and 02.00–06.00 hours. There are, however, di?erences according to age, in that, for instance, infants sleep for most of the 24 hours; during adolescence there is also an increase in the duration of sleep. Sleep requirements fall later in life, but there are wide genetic di?erences in the amount of sleep that people require and also the time at which they fall asleep most readily.

The internal clock can be disturbed by a variety of external factors which include irregular sleeping habits due, for instance, to shift work or jet lag. Sleep is also more likely to occur after physical exertion, reading and social activity. The duration and intensity of exposure to light can also modify sleep profoundly. Light promotes wakefulness and is the main factor that adjusts the 25-hour internal rhythm to the 24hour daily cycle. Neural connections from the retina of the EYE act on an area in the brain called the supra-chiasmatic nucleus which stimulates the pineal gland which produces MELATONIN. This is thought to trigger the range of neurological and metabolic processes that characterise sleep.... rapid-eye-movement (rem) sleep

Rapid-eye-movement is a stage during SLEEP in which the eyes are seen to move rapidly beneath the lids and during which dreaming occurs. It occurs for several minutes at a time approximately every 100 minutes.... rem sleep

A sleep apnoea is conventionally de?ned as the cessation of breathing for ten seconds or more. Apnoeas, which affect around 5 per cent of adults and are markedly more common in men, may occur as frequently as 400 times per night. They can be due to a failure of the physiological drive to breathe (central sleep apnoeas) but much more often are due to a transient obstruction of the airway between the level of the soft PALATE and the LARYNX (obstructive sleep apnoeas) when the airway dilator muscles over-relax. Any factor such as alcohol or sedative drugs that accentuates this, or that makes the airway narrower (such as obesity or large TONSILS), will tend to cause sleep apnoeas.

Vigorous respiratory movements are made to overcome the obstruction during each apnoea. These are associated with snoring and snorting noises. The apnoea ends with a mini-arousal from sleep. As a result, sleep becomes fragmented and sleep deprivation, manifested as sleepiness during the day, is common. This may result in accidents – for instance, at work or while driving – and sleep apnoea is also linked with an increased risk of STROKE, heart attacks and HYPERTENSION.

The diagnosis of sleep apnoea has recently been facilitated by linking specially designed software with ELECTROCARDIOGRAPHY performed during sleep, with minimal disturbance of the subject.

Initial treatment is directed at correcting the cause (e.g. obesity), but if the apnoeas persist or are severe a nasal mask and pump which introduces air under slight pressure into the upper airway (continuous positive airway pressure, CPAP) is almost invariably e?ective.... sleep apnoeas

Insufficient sleep.

Irritability and a shortened attention span may occur after a short night’s sleep.

Longer periods without sleep leave a person increasingly unable to concentrate or perform normal tasks.

Three or more sleepless nights may lead to hallucinations and, in some cases, to paranoia.... sleep deprivation

See night terror.... sleep terror

Equipment for increasing the mobility of people who have a disorder that affects their ability to walk. Aids include walking sticks, crutches, and walking frames.... walking aids

Most children walk by around 15 months of age. Delayed walking may be suspected if the child is unable to walk unassisted by 18 months (see developmental delay).... walking, delayed

There are three main groups of SLEEP disorders:

Parasomnias These include medical disorders such as ASTHMA, ANGINA PECTORIS or EPILEPSY which are made worse by sleep, and a range of behavioural alterations which are usually related to a speci?c sleep stage or to a change from one state of sleep to another. Sleepwalking, night terrors, and nightmares are examples.

Insomnia Insomnia is de?ned as a di?culty in initiating or maintaining sleep. It affects around 15 per cent of the population at any one time, and is often due to a poor pre-sleep routine (e.g. taking excessive stimulants such as ca?eine); unsatisfactory sleep due to poor environments such as an uncomfortable bed or a cold or noisy bedroom; anxiety and/or depression; or occasionally to a physical problem – for example, pain – or a medical disorder associated with sleep such as obstructive SLEEP APNOEAS or periodic limb movements.

Excessive daytime sleepiness This is usually due to sleep deprivation caused either by inadequate duration of sleep, or by poor quality of sleep. The individual’s lifestyle is often a cause and modi?cation of this may relieve the problem. Other common causes of excessive daytime sleepiness are depression, obstructive sleep apnoeas, periodic limb movements, excessive alcohol or other drug intake, and, less commonly, NARCOLEPSY.... sleep, disorders of

Whether you are dealing with sleepless nights or you feel too tired during the day, you can try to solve this problem with tea. As it is a natural beverage, it brings along various other health benefits. Find out more about teas for sleep! Sleep problems tea can solve Sleep can become a problem when we either can’t sleep during the night or we feel like we don’t  get enough sleep. Sleepless nights can have various causes. We can get them because we feel stressed, anxious or depressed. They can also be caused by the medication we might be taking. Various diseases can lead to sleep problems, as well. These include asthma, various allergies, Parkinson’s disease, hyperthyroidism, acid reflux, kidney disease, cancer or chronic pain, or even sleep-related diseases such as sleep apnea, narcolepsy, or restless legs syndrome. Lastly, beverages that contain caffeine can lead to sleepless nights. As for feeling tired despite having slept during the night, this happens mostly because stress and anxiousness, or because of various diseases (celiac disease, anemia, underactive thyroid, diabetes). Tea can help reduce both sleeping problems and fatigue. Though not as strong as medication, it counts as an important, natural element of the treatment. Varieties of tea for sleep There are a few types of tea that can help you when you’re dealing with sleepless nights. Valerian tea is often recommended when you’ve got trouble sleeping. This tea allows endomorphins in your body to be released easier and therefore reduces sleep problems. Chamomile tea is another tea for sleep; it reduces stress and anxiety levels and can therefore help you relax and get a good night’s sleep. Lavender is also known for helping people relax, so drinking a cup of lavender tea before bed can help a lot, too. Other herbal teas with similar properties include basil tea, catnip tea, fennel tea, honeybush tea, kava tea, lemon balm tea, motherwort tea, passion flower tea, peppermint tea, reishi tea, schizandra tea, and skullcap tea. Side effects of tea for sleep While these types of tea help when it comes to sleeping problems, consumption of each tea can lead to a few side effects. This is why it is recommended that you talk with your doctor first, before deciding to drink tea daily, as part of your treatment. Make sure you won’t get allergic reactions caused by the tea’s main ingredient. Also, avoid teas for sleep (and most types of tea) during pregnancy and nursing periods. Chamomile tea should not be drunk by people with bleeding disorders. Valerian tea should not be consumed in large quantities, as it might lead to headaches and stomach problems. Tea to get rid of fatigue The types of tea that can help you get rid of fatigue are the ones you should not drink when you’ve got sleeping problems. A cup in the morning can be safe, though you definitely shouldn’t drink it at night, before bed. Tea that contains caffeine helps fight off feelings of tiredness. These include the types of tea made from the Camellia Sinensis plant: green tea, black tea, white tea, and oolong tea. Drinking a cup of one of these teas, in the morning, can increase your mental alertness and scare off fatigue. However, make sure you can drink types of tea that contain caffeine. If caffeine is not good for you, it might lead to unpleasant side effects: headaches, nervousness, sleep problems, vomiting, diarrhea, irritability, irregular heartbeats, tremors, dizziness, or ringing in the ears. No matter the problem, whether you have trouble sleeping or you feel tired during the day, choose a type of tea that can help you. This hot beverage can count as a natural treatment which will also bring other health benefits. Enjoy your cup of tea for sleep!... tea for sleep

(OSAS) see obstructive sleep apnoea.... obstructive sleep apnoea syndrome

(SAS) see obstructive sleep apnoea.... sleep apnoea syndrome

(SDB) abnormal patterns of respiration seen during sleep. *Obstructive sleep apnoea is the most common SDB; other types include central *sleep apnoea, such as *Cheyne–Stokes respiration.... sleep disordered breathing

the measured distance that a patient can walk before he or she is stopped by pain in the muscles, usually the calf muscles, or breathlessness. It is a useful estimate of the degree of impairment of the blood supply. See claudication.... walking distance

(OSA, obstructive sleep apnoea syndrome, OSAS) a serious condition in which airflow from the nose and mouth to the lungs is restricted during sleep, also called sleep apnoea syndrome (SAS). It is defined by the presence of more than five episodes of *apnoea per hour of sleep associated with significant daytime sleepiness. Snoring is a feature of the condition but it is not universal. There are significant medical complications of prolonged OSA, including heart failure and high blood pressure. Patients perform poorly on driving simulators, and driving licence authorities may impose limitations on possession of a driving licence. There are associated conditions in adults, the *hypopnoea syndrome and the upper airways resistance syndrome, with less apnoea but with daytime somnolence and prominent snoring. In children the cause is usually enlargement of the tonsils and adenoids and treatment is by removing these structures. In adults the tonsils may be implicated but there are often other abnormalities of the pharynx, and patients are often obese. Treatment may include weight reduction or nasal *continuous positive airways pressure (nCPAP) devices, *mandibular advancement splints, or noninvasive ventilation. Alternatively *tonsillectomy, *uvulopalatopharyngoplasty, *laser-assisted uvulopalatoplasty, or *tracheostomy may be required.... obstructive sleep apnoea