Archive for the ‘Sleep’ Category

• Sleeping Bag Advice – Which Sleeping Bag Should I Buy?

  Date: 2009.05.24 | Category: Sleep | Response: 0

  SLEEPING BAGS

  About Sleeping Bags

  Being comfortable and warm at night is crucial for enjoyment of the outdoors, so a good sleeping bag is a vital piece of camping equipment. It’s hard to appreciate a beautiful dawn when you’ve spent most of the night shivering in an inadequate bag. So here’s some advice on helping to choose a sleeping bag.

  First and foremost, a sleeping bag must keep you warm. The sleeping bag filling is of importance here, but so is design. The closer fitting a sleeping bag, the warmer it will be so the best shape is a tapered one (or mummy style sleeping bag). An adjustable sleeping bag hood is needed too, as much heat is lost through the head. However, for comfort, you also need a sleeping bag you can stretch out and curl up in rather than one that feels like a strait-jacket. The big decision to be reached is about the filling. There are three choices: waterfowl down, polyester fill and fibre-pile. Each has advantages and disadvantages.

  Down Sleeping Bags Vs Synthetic Sleeping Bags

  Down sleeping bags have the best warmth for weight ratio, packs up smallest and is long lasting, but loses all warmth when soaked, is slow to dry, hard to clean and is quite expensive. Polyester sleeping bags using materials such as Hollowfil, Quallofil and Polarguard are quick drying, resistant to damp and reasonably priced but bulkier and heavier than down for equivalent warmth and are shorter lived. Fibre-pile is warm when wet, quick drying, long lasting and inexpensive, but again bulkier and heavier than down for equivalent warmth.

  Where weight is critical, down is the best choice, For shorter trips or car camping, polyester is suitable, whilst for bivouacing or snowholing where your bag is likely to get damp, pile is worth considering. Whatever the fill, sleeping bags come in various weights with season or temperature ratings. Be warned, these are guidelines only. Cold sleepers may need an extra ‘season’ to ensure a warm night, whilst warm ones may be able to get away with a lighter bag than that suggested for the time of year. You can of course ‘stretch’ the warmth of a bag by wearing clothes in it, using a sleeping bag liner, and all sleeping bags will perform better if used with an insulating mat underneath. Sleeping bags are manufactured by most of the top outdoor manufacturers including: Snugpak, Cumulus Sleeping Bags, Mountain Equipment, RAB and The North Face.

  Sleeping Bag Season Rating

  This tells you, roughly, at what time of the year the sleeping bag can be used comfortably. However, the season rating cannot be too specific as toleration of cold varies from person to person.

  1 season sleeping bag – use in summer

  2 season sleeping bag – use from late spring to early autumn

  3 season sleeping bag – use through spring, summer and autumn

  4 season sleeping bag – low level use all year round

  The above refers to general use, not high level mountain use, i.e. 4 season sleeping bags are sometimes not suitable for winter expeditions. Please call 01925 411 385 to speak with a member of the CheapTents.com’s expert team for more information on which sleeping bag is most suited for your needs if you have any doubt.

  Sleeping Bag Materials

  The Filling: Its purpose is to trap air and prevent its circulation. The air is heated by your body and because it is retained around you, provides the warmth necessary to keep you comfortable whilst you sleep.

  Down Sleeping Bags: Nature’s own is still the best sleeping bag insulating material. It is lightweight with excellent loft (fluffs up well to trap air) and is extremely compressible to give a small pack size. Down has excellent “drape” properties, settling around the body and eliminating the drafty gaps sometimes left by stiffer synthetics. However, down is a poor performer when wet, unlike some polyester fibres which resist moisture well. Down sleeping bags also tend to be more expensive.

  Synthetic Sleeping Bags: Heavier, bulkier and with a much shorter life-span than down, yet cheaper, easier to clean and the best choice for wet conditions where it still offers reasonable insulation. Synthetic fillings are made up of polyester fibres of various construction. The most common is ‘hollowfibre’ where short tubular fibres have a hollow centre for trapping air, giving good insulating properties and reducing weight.

  ‘Kontrol’, from the UK manufacturer John Cotton is a latest innovation giving small pack size but high loft capabilities for sleeping bags. NB: The weight of filling in a sleeping bag is not an accurate indicator of its thermal performance as the quality of fillings vary. A high-quality sleeping bag filling may cost a bit more but gives a better warmth to weight ratio.

  Shell Fabrics: These hold the sleeping bags filling in place. A close weave on the outer helps repel water/wind penetration as well as keeping the filling in. Probably the most common fabric used today is a lightweight nylon which also offers low bulk. In some instances this will be Ripstop on the outer. This means it incorporates a reinforced, fiber mesh to prevent tearing and, because of the increased strength gained, an even lighter material can be used. Some nylon sleeping bag shells are coated to make them more water resistant, yet still allow the body to ‘breath’. ‘Pertex’ fabric also does this. In addition it wicks moisture away from the body to keep you dry.

  Occasionally cotton is used as a lining, as this is very comfortable to sleep in but the penalty is extra bulk and weight and it is slower to dry. In some bags, a metalised layer is incorporated between the filling and shell to reflect back body heat. This can improve the performance of a bag by up to 15%.

  Sleeping Bag Construction

  There are various methods of keeping the filling in place.

  Stitched Through Sleeping Bags: Quilting holds the filling in channels or baffles. However, you get cold spots along the stitch lines so this method is unsuitable for cold weather bags.

  Double Layer Offset: As above but using 2 layers. Offsetting the quilting helps eliminate the problem of cold spots in your sleeping bag.

  Profile: A ‘no stitch through’ construction which produces 30% extra loft. Special resins enable the insulating fibres to support themselves inside the sleeping bag, without the need for any quilting. This means no stitch lines, and hence, no cold spots.

  Sleeping Bag Features

  Sleeping Bag Zips: Allow for easy access and, as all our zips are of the ’2-way’ type, there is an option to open the foot of the bag for ventilation on warm nights giving more flexibility to the upper temperature rating. As a zip creates a cold spot, all of them have a zip baffle – a tube of insulation that backs the zip and ensures you stay warm inside. All of our zipped bags are available with either left or right hand zips. If you wish to zip 2 bags together, get one of each. Otherwise, we recommend a left hand zip for right hand users and a right hand zip for left hand users. Our zips have an anti-snagging feature to prevent them ‘catching’ either the baffle or the bag edges.

  Sleeping Bag Hoods: All our sleeping bags have tailored hoods adjusted by drawcord.

  Neck Baffles: This insulated collar is to be found on most of our sleeping bags. A drawcord brings this snugly around you ensuring no cold drafts down the back of the neck.

  Box Foot: Here, the foot section is created by a circular piece of insulated fabric, creating a ‘mummy’ shape which gives plenty of room for the feet.

  Sleeping Bag Stuff Sacks: Most sleeping bags come with a stuff sac for easy transport. Most incorporate compression straps to reduce pack size.

  IMPORTANT: Storage

  When not in use, your sleeping bag should be stored loose. Continual compression is bad for the filling and will reduce the life of your sleeping bag. Cumulus down sleeping bags are sold with a storage sack as well as a compression sack.

• Sleep Disorders

  Date: 2008.08.27 | Category: Sleep | Response: 0

  Sleep Disorders

  Stage 1: mixed frequency, low voltage. Alfa ? (8-12 Hz) and Theta ? (4-6 Hz). Stage 2: low voltage, slower frequencies. Contains sleep spindles (12-14 Hz) and high amplitude ‘k’ complexes Stage 3 & 4: high amplitude, low frequency Delta ? (2 Hz) waves. Stage 3 characterized by < 50% ? waves with sleep spindles. Stage 4 by > 50% ? waves but no sleep spindles. Stage 3 & 4 comprise slow wave sleep (SWS). As sleep progress through stages 1 to 4 low frequencies increase at the expense of the higher frequencies which are characteristic of waking.

  REM sleep (paradoxical sleep):

  The EEG shows a low voltage, mixed frequency spectrum with characteristics of cortical activation. It is associated with rapid eye movements, signs of autonomic arousal and paradoxical low muscle tones, and this is when dreams occur.

  Sleep architecture:

  From waking, individuals pass through stages 1 to 4, then into REM sleep. REM sleep then alternates with non-REM. REM compromise 20% of total sleep time, and occurs at 80 to 90 minutes intervals. Stages 3 and 4 comprise 15-20% of total sleep time. The majority of time is spent in stage 2. SWS occurs mainly early on in sleep with REM sleep later. SWS and REM sleep are highest in neonates, and decrease in amount with increasing age.

  Function of sleep:

  Theories about the function of sleep include conservation of energy versus brain or body restoration. REM sleep has been proposed to reflect brain functions, and SWS to be associated with bodily functions (related to the amount of energy expanded, it is increased with exercise and decrease with hypothyroidism). It has been suggested that sleep can be core and optional sleep based on observations that:

  Only 30% of total sleep lost is regained after sleep deprivation, especially SWS and REM. Short sleepers have similar early sleep pattern to longer sleepers Gradual sleep reduction down to five hours is well tolerated.

  Control of sleep:

  The reticular activating system is involved in arousal, and the induction of sleep is active rather than passive process. The Yerkes-Dodson curve describes the phenomena of increasing then decreasing performance with increasing arousal. The peak is reached and exceeded more quickly for difficult than easy tasks. Poor sleep affects the ability to perform simple, mundane tasks but not more complex ones which require more attention. Drugs can affect both performance (via drowsiness) and sleep, for example, antidepressants, antipsychotics, benzodiazepines, antihistamines and alcohol.

  v Clinical Syndromes:

  Epidemiology:

  Insomnia: 30% in one year Nightmares: occasional in 50% of adults, regular in 1% Sleep apnoea: 4-8% of men; 2-4% of women Narcolepsy: 0.15%

  Classifications:

  Dysomnias: poor sleep Medical/psychiatric sleep disorder: i.e. secondary Parasomnias: abnormalities during sleep Specific sleep disorders.

  1. Insomnia: this represents lack of sleep, poor quality of sleep or reduced daytime performance. It is probably the commonest complaints presented to primary health care; for example in the USA 42% prevalence. Hypnotic use is still common despite changes in guidelines (esp. in this country). Primary insomnia is rare. Causes of insomnia include:

  Psychiatric disorders (36%) Psychophysiological insomnia ‘sleeplessness phobia’ (16%). Features include: the complaint of insomnia and reduced performance when awake, trying too hard to get to sleep, tension, physical symptoms, increased sleep latency, reduced sleep efficiency and increased number of awakenings. Medications, illicit drugs and alcohol (12%) Periodic limb movement disorders (12%) Sleep apnoea (6%) Pseudo-insomnia (6%) Sleep-wake schedule disorder (6%) Medical disorders (6%)

  However, social and personal factors are also very important in determining who present, for example women report insomnia twice as often as men, and rates are higher in the unemployed

  2. Parasomnias: these are acute, undesirable, specific, episodic physical phenomena which occur during, or are exacerbated by sleep. There is an interaction between psychological (esp. stress) and biological factors. Generally treat with reassurance, education and practical advice. These occur in different stages of sleep:

  Ø SWS: disorders of arousal; sleepwalking and night terrors. Sleepwalking is often exacerbated by excessive sleepiness. Night terrors occur early in sleep, the individual is difficult to rouse and generally has no recall. Ø REM sleep: patients rouse easily. These are usually nightmares or dream anxiety attacks which are frightening, with clear recall. They may be related to psychological precipitants, fever or drug withdrawal (BDZ, antidepressant, alcohol). Other disorders are sleep-related cluster headaches and sleep related asthma; the REM sleep behaviour disorders which involve loss of the usual atonia in REM sleep so the individual acts out dreams which are often violent. Ø Other Parasomnias: Enuresis (patients may have different sleep patterns and therefore not able to sense the need to urinate); bruxism (teeth-grinding); head banging; familial sleep paralysis.

  3. Specific sleeps disorders:

  Ø Narcolepsy: characterized by hypersomnolence, cataplexy, sleep paralysis and hypnogogic hallucinations (tetrad is Gelineau’s syndrome). 50% also have major affective disorder and / or personality problems. Aetiology suggests genetic cause as family history is common and HLA-DR2 found in 99%. Onset is generally in the teens or twenties. Sleep attacks are irresistible in boring situations (like this lecture!), and cataplexy is often related to emotions. There is a short REM latency. Narcolepsy can be treated with psychostimulants, and support groups are helpful. Ø Periodic limb movement disorder: there are repetitive and stereotyped movement during sleep and the patient is often unaware. It may lead to poor sleep and daytime fatigue, also depression and anxiety. Found in narcolepsy, obstructive sleep apnoea, Parkinson’s disease and metabolic disorders. It can be aggravated by tricyclics and withdrawal from BDZ. Ø Kline-Levine syndrome: this occurs generally in adolescent boys, and is characterized by periods of hypersomnia and overeating, often with change in libido.

  4. Other sleep-related problems:

  Ø Circadian rhythm disorders: this describes changes in the timing of sleep, for example in people on shifts and with jetlag. Ø Daytime sleepiness: Narcolepsy, obstructive sleep apnoea, sleep-related motor disorders, depression, post-viral fatigue, head injury, metabolic, toxic and drug related factors, essential hyper-somnolence, and older age can all cause daytime sleepiness. v Assessment Patient’s description of the problem, including the onset, length and quality of sleep, and any daytime drowsiness or reduced performance Objective observations by patient and spouse/relative. Possible general medical, psychiatric or drug problems. Details of sleep environment and hygiene Drug history, both prescribed and recreational. Current circumstances and stress Sleep diary including caffeine, alcohol and drugs.

  People often overestimate the length of time to get to sleep, even to the extent that good and poor sleepers can have similar sleep pattern. However the quantity of sleep can be relied on in assessing the presence of insomnia.

  v Management

  1. General advice:

  Treatment of any underlying cause. Education and advice on sleep hygiene. Optimizing the temperature at the room Encouraging a regular routine Exercising late in the afternoon Small food intake in the evening Relaxation techniques Advice about problem solving and dealing with intrusive thoughts (CBT can be used and has good evidence based results).

  2. Role of drugs in sleep:

  •a)    Drugs used to improve sleep:

  Particularly benzodiazepines (BDZ), which can be used in short-term treatment for poor sleep associated with acute stress. BDZ reduce REM and SWS, increase stage 2. Tolerance and REM sleep rebound occur on discontinuation. Barbiturates are no longer should be used due to its narrow therapeutic window, high addictiveness, tolerance and death in overdose.

  Zopiclone (new generation partial BDZ, only used as hypnotic) increase SWS, and although early reports claimed less tolerance and dependence, recently this has been disputed.

  New Melatonin derivatives medication has been just licensed for sleep, some evidence point toward better results with elderly, and may be autism. These have few side effects and do not interfere with sleep architecture.

  •b)    Drugs used to reduce sleepiness:

  These are for example amphetamine, pemoline and selegiline. These reduce total sleep, REM and SWS, delay sleep onset and cause fragmented sleep.

  •c)     Drugs used to treat psychiatric disorders:

  Antidepressants: some are alerting e.g. Prozac (fluxoetine), MAOI; some are sedatives, which is generally related to their anticholinergic properties (most tricyclic), or antihistaminic (Mirtazepine). In general, antidepressants suppress REM sleep. Interestingly, sleep deprivation is still used as treatment for depression and the target is to reduce REM sleep. Mood-stabilizers: Lithium reduces REM sleep and delay onset. Carbamazepine reduces REM sleep and increase SWS, and can cause initial drowsiness. Anti-psychotics: These reduce periods of wakefulness, increase or decrease REM sleep, depending on the dose. Total and REM sleep are reduced on stopping.

  •d)    Non-psychotropic drugs:

  These can affect sleep by crossing the BBB, or by causing or exacerbating a disorder which disrupt sleep (e.g. sleep apnoea). Common causes of sleep disturbance include appetite suppressants, anti-emetics, anti-histamine, corticosteroids, cardiovascular drugs and hormones.

  e)     Recreational drugs:

  Alcohol promotes sleep in small amounts nut in larger amounts causes insomnia later in the night due to rebound and withdrawal effects. Its effect depends on the level of sleep deprivation, and interactions with other drugs. Nicotine can disrupt sleep. Caffeine causes an increase number of arousal and decrease REM sleep. It has a half-life of five hours. Withdrawal symptoms also occur which disrupt sleep.

  •f)      Illicit drugs:

  Cannabinoids reduce REM sleep, and increase SWS initially but decrease it after several days. Habitual use leads to excessive sleeping and lassitude, with sleep disturbance on withdrawal. Narcotic analgesics cause a drowsy state followed by reduce REM and SWS. Sleep disturbance occurs on withdrawal. Cocaine reduces total sleep, SWS and REM sleep. Excessive sleeping occurs on withdrawal (rebound). Hallucinogens (e.g. LSD) do not affect sleep directly except by ‘ bad trips’

  •g)    Drugs withdrawal:

  Sedatives and hypnotics cause rebound insomnia usually for one week but can be for up to two months. Insomnia is more severe but less prolonged for drugs with shorter half-life. Chloral hydrate gives fewer problems with withdrawal but is less efficacious.

  Abrupt withdrawal of antidepressant can lead to short-lived rebound insomnia and panic. Antipsychotics rarely cause dependence or withdrawal (therefore small dose, below the therapeutic dose for psychosis treatment, are used to aid sleep in some patients)