According to experts we’re sleeping less than ever before. In fact, chronic sleep deprivation has been called ‘‘the disease of our times’’.
About a 100 years ago people slept for an average of nine hours a night; today it’s closer to seven hours. With the exception of the Margaret Thatchers and Helen Zilles of this world, who claim to flourish on fewer than four hours, we simply haven’t been getting enough shut-eye since electricity was invented.
But why do we have to sleep?
Survival is the simple answer. Scientists today know sleep is a complicated but necessary rest time for the body.
Glucose reserves are replenished, brain networks that would otherwise decline are given a workout and essential cycles, such as the secretion of growth hormones, take place. Sleep also helps organise the memory, refresh the mind and improve learning abilities, says Peet Vermaak, neurophysiologist at The Pretoria Sleep Lab.
To understand just how important sleep is for survival think about what happens when you don’t get enough: you’re grumpy, irritable and forgetful, your moods swing, you can’t concentrate, your memory fails and even your speech is affected. Sleep deprivation has a serious, negative impact on your brain.
Breaking the sleepless record
This impact can be felt after just 17 sleepless hours: at that point your judgment and skills are the same as someone who has had two glasses of wine and has a blood alcohol level of 0,05 per cent – enough to land you behind bars. American Randy Gardner holds the record for going without sleep. He stayed awake for 11 full days in 1965. After four days he started hallucinating.
Then he became delusional, believing he was a famous football player. The National Institute of Neurological Disorders and Strokes in the US studied rats that were deprived of sleep. The animals survived for just three weeks even though they have a natural lifespan of three years.
Sleep is by no means an unconscious resting time. It’s an active, dynamic process during which the brain never switches off, says Professor Gerhard Jordaan, Stellenbosch University’s head of adult psychiatry. ‘‘The body uses almost as much energy to sleep as when we’re awake.’’
Neurotransmitters that ‘‘switch off ’’ the neurons that keep us awake, and therefore make us sleepy, control sleeping and waking states. The chemical adenosine that builds up in the bloodstream during the day also makes us feel tired.
At night while we’re asleep adenosine is broken down – but only when we’re in deep sleep. If we don’t get enough deep sleep adenosine isn’t processed properly – and that’s why we wake up tired.
How much sleep is enough?
There’s no magic amount of sleep required for optimal health. Each individual has different sleep needs, scientists at America’s National Sleep Foundation say. Some of us need just five hours a night; others can’t manage with fewer than 10.
The number varies with age. Babies should get about 16, teenagers up to nine and a half, and most adults between seven and eight hours a night.
Teenage sleep patterns differ from those of adults: it’s normal for teenagers to want to go to bed late and sleep late.
And while Granny sleeps lightly and for shorter periods she still needs as much deep sleep as she used to when she was younger. Her afternoon nap is important and she needs more sleep at night for sufficient deep rest.
Each individual has a basal sleep need, explains Dr Frans Hugo of the Panorama Psychiatry and Memory Clinic in Cape Town. Basal sleep need is the amount of sleep you require to rise refreshed and awake. If this isn’t satisfied a sleep debt builds up. Sleep debt is the amount of sleep you’ve lost. You feel and show the symptoms of sleep debt and deprivation when you’re awake.
Most people fall asleep within 15 to 20 minutes of going to bed. If you fall asleep in fewer than seven minutes you have sleep deprivation, Dr Hugo says. Overworked people with sleep debt hit the bed like a sack of potatoes and say they went out like a light.
Adults need between six and eight hours of basal sleep a night but things get complicated when sleep debt starts to interfere with basal sleep need. A mother with a young baby may finally be able to sleep through several nights but the previous weeks’ lack of sleep means she will still be tired when she wakes up because of her accumulated sleep debt.
‘‘That’s why we have to accommodate the basal sleep need in a 24-hour cycle,’’ Dr Hugo says. The good news is researchers believe sleep debt can be reduced – provided sleep is made as much of a priority as eating. That’s why there’s merit in the claim a mom should sleep when her baby does.
Not getting enough sleep can affect your judgment and reflexes. Studies show medical students who suffer from a shortage of sleep make more mistakes. American scientists warn too little sleep has serious health implications.
Obesity, diabetes, heart disease, psychiatric illness, depression, drug abuse, learning disabilities and car accidents are all linked to sleep deprivation.
On the other hand too much sleep (more than 10 hours a night) can be a strong indication of depression and other conditions.
The importance of dreams
Dreams occur almost exclusively during very deep sleep or REM sleep. Scientists can still only guess why we dream. What’s clear however is we all spend about two hours a night dreaming even though we may remember only five per cent of our dreams.
A dream’s journey through the brain begins in the midbrain – specifically the pons – and ends in the cerebrum, the part of the brain where learning, organisation, memory and thought processes occur.
This route has caused scientists to speculate that dreams are important for the healthy functioning of these processes. It would also explain why REM sleep is essential for the development of the brain in children, and why babies need so much of this type of sleep.
There are several explanations for the intimate connection between dreams and memory, and especially the question of why we find it so difficult to remember our dreams. Some biologists say dreams are the brain’s way of sorting and deleting unimportant information so it doesn’t become overwhelmed and stop working.
Dr Hugo emphasises research into the reasons for REM sleep and dreams hasn’t yet delivered any hard scientific facts. ‘‘We do know REM sleep and dreams are essential for memory. Without REM sleep the electrical currents in the brain that make up our memory literally collapse. During dreams in REM sleep the memory currents are reactivated and more firmly fixed.’’
During dreams, Dr Hugo explains, memory networks contact other networks, starting a chain reaction. This could explain why, during the same dream, different themes occur that are apparently completely unrelated. Dream events also last as long as real-life ones and are experienced in colour.
Whether you remember your dreams depends on which sleep phase you’re in when you wake up, he adds. If you wake up during REM sleep you’ll remember your dream.
What happens when you fall asleep?
An electroencephalograph (EEG) enables scientists to distinguish five phases in each cycle. The phases of sleep progress in a cycle from phase one to REM (rapid eye movement) sleep, after which the cycle starts again.
PHASE ONE is light sleep, when you’re still half awake. Your muscles relax, your pulse slows and your eyes move from corner to corner. This phase lasts just a few minutes. The slightest disturbance will wake you and you may experience a sensation of falling. That’s because your muscles have started to relax.
PHASE TWO You spend almost half of your total sleep time in phase two, called true sleep. It lasts for almost 20 minutes at a time and your heartbeat, breathing and brain waves slow down.
PHASE THREE is the start of deep sleep. You’re now thoroughly relaxed. In this phase huge, slow brain waves called delta waves begin to occur. Your breathing and heartbeat decrease to their lowest possible levels.
PHASE FOUR The brain produces almost only delta waves and it’s very difficult to wake you. If you’re disturbed during deep sleep you’ll struggle to adjust to being awake and will feel disoriented and groggy. Deep sleep is the phase during which some children experience bedwetting, night terrors or sleepwalking.
PHASE FIVE The last phase of the cycle is REM sleep. It starts about 70 to 90 minutes after you’ve fallen asleep. Adults spend about 20 per cent of their total sleep time in this state while for babies it’s about 50 per cent. REM sleep lasts longest at night. If you doze off during the day the REM phase is longer during morning naps than in the afternoon. REM sleep may play an important role in brain development.
Therefore the more REM sleep your child gets the better. As your baby grows and the brain develops less time is spent in REM sleep.
During REM sleep your brain rhythms look similar to those when you’re awake. Your eyes jerk rapidly in various directions, breathing becomes more rapid and blood pressure rises. But because messages from the brain stem to the rest of the body are ‘‘switched off ’’ your muscles become temporarily paralysed. This is essential – imagine what would happen if you acted out your dreams! Despite the temporary paralysis men may still experience erections.
It’s difficult to wake you from REM sleep and if it happened you would be disoriented and your thoughts bizarre. This is also when you’d be dreaming about that giant hairy worm chasing you and a scantily clad Angelina Jolie (or Brad Pitt) over the lip of a volcano – before you simply fly away.
REM sleep is an extremely sensitive state, affected by food and drink (particularly caffeine), medication (asthma treatments, for example), alcohol, diet pills (which contain stimulants), diuretics, cigarettes and extreme cold or hot environments.
If REM sleep is interrupted just once during the night your body doesn’t return to the normal sleep cycle when you go back to sleep – it goes directly back into REM sleep to try to catch up. Mothers of young children spend more time in REM sleep than in any other phase because of the constant interruptions of their sleep cycle. After REM sleep the entire sleep cycle starts again.
Sleep has recurring cycles – between three and five a night – of 90 to 110 minutes each. The cycles of sleep become more shallow as the night progresses.
DEEP SLEEP Is also the phase when hormones such as testosterone and growth hormones are secreted. In adults growth hormones ensure cells, skin, bone tissue and muscles remain healthy – your proverbial beauty sleep. In babies and children they facilitate growth and trigger puberty.
Sleep and your body's internal clock
The secret of your unique sleep needs can be revealed by considering your body’s internal clock, also called the circadian clock (circadian comes from a Latin word meaning ‘‘around the day’’). It refers to the body’s response to external things – sunlight, for example – during a 24-hour cycle.
Your circadian clock is in the hypothalamus. It’s a structure the size of a pinhead; it responds to light received by the eye and regulates the secretion of melatonin, the sleep hormone. In all people, with the exception of teenagers, the amount of melatonin secreted increases from sunset onwards – it’s literally the body’s Mr Sandman.
This part of the brain also synchronises other functions linked to going to sleep and waking up, including body temperature, hormone secretion, urination and blood pressure.
If you visit someone in Australia you fly from west to east and cross several time zones. This interferes with your circadian rhythms in the worst possible way and results in jet lag. Crossing time zones in the other direction – from east to west (from Australia to South Africa, for example) also causes jet lag but not to the same degree.
Today artificial melatonin supplements and light therapy (doctors apply bright lights during sleep to restore normal biorhythms) are used to combat the effects of jet lag. Melatonin should however be used only under medical supervision. It builds up in the body and its side-effects haven’t yet beenthoroughly researched.
Jan Top of the Panorama Sleep Clinic says shift workers suffer from a similar type of exhaustion because their bodies’ normal exposure to light is disturbed. Fatigue among shift workers has resulted in serious industrial disasters.
The nuclear accidents at Chernobyl and Three Mile Island, the Exxon oil spill and most of the motor vehicle accidents on the road between Laingsburg and Beaufort West have been linked to sleep deprivation. Shifts should be limited to eight hours and the body must be allowed a rest period before shifts change, Top says.
Did you know?
Because of the body’s circadian clock there’s a greater risk of dying between 4-6 am. Most heart attacks occur in the early hours of the morning. Your body weight is at its lowest between 9 am and noon while reaction time peaks at about 4 pm. Asthma attacks typically happen between midnight and 6 am and most women give birth naturally around 1 am.
Good sleeping habits
Keep a notebook handy and write down anything that’s worrying you and may be keeping you awake.Learn to fall asleep without thinking about it. Don’t wait to ‘‘switch off ’’.
Visualise something nice or replay a movie you enjoyed in your head. Dr Frans Hugo of the Panorama Psychiatry and Memory Clinic says a colleague loves Audis and every night visualises himself walking into a showroom, getting into the flashiest car and driving away – straight into dreamland.
Avoid stimulants such as coffee, chocolate and nicotine after 6 pm. Alcohol should be consumed early in the evening and in moderate amounts. It may relax you at first but your brain could switch back on in the middle of the night after the alcohol has been metabolised.
Teach your brain that bed is only for sleep and sleep is only in bed.
Don’t toss and turn. If you’re not asleep after 10 or 20 minutes get up and do something boring somewhere else – you could even try reading the telephone directory.
Don’t watch television or videos, read an exciting book or try to work.
Don’t get anxious if you can’t sleep for a few nights. You’ll soon catch up. ‘‘Comfort yourself with the thought you’ll probably sleep better the next night or the one after that. The worst that can happen is you’ll be tired and irritable the next day,’’ Dr Hugo says.
Follow the same routine every day. Your brain will learn to associate it with sleep. Exercise can help but should be done early in the evening. A hot bath and soothing music can also be effective.
Try to sleep until sunrise.
What about sleeping pills & other remedies?
Doctors generally try to treat sleep disorders without resorting to medication, and especially without the use of benzodiazepam sleeping pills. Not all sleeping pills are the same – some are definitely more addictive and dangerous than others.
Sleeping pills can be fatal in large doses and particularly if they’re taken with alcohol or anything else that can make you drowsy. Benzodiazepams are extremely addictive and potentially dangerous – they can cause birth defects in foetuses and leave newborns with respiratory problems, among other things, if a mother takes them during pregnancy. Children shouldn’t use them since it may delay physical and mental development.
Because benzodiazepam has a depressant effect it can be dangerous to people with respiratory illnesses, depression, psychiatric conditions, muscle disease, porphyria, sleep apnoea, epilepsy, glaucoma, kidney or liver trouble or alcohol or drug problems.
Under no circumstances should you take sleeping pills not prescribed specifically for you. You must also follow the recommended dosage exactly.
Types of sleeping pills
There are mainly two groups of sleeping pills: the benzodiazepams (such as Halcion, Normison, Loramet, Dormicum, Dormonoct and Hypnor) and the new generation of non-benzo diazepams (such as Stilnox and Imovane).
Benzodiazepams help with anxiety and insomnia but they’re also used as a sleeping pill before anaesthetic, as a light anaesthetic, in the treatment of alcohol abuse and as a muscle relaxant.
Some benzodiazepams induce sleep almost immediately but their effect lasts just a few hours. Others work for more than 12 hours. The faster they take effect the more addictive they are.
Dormicum, Dormonoct and Halcion work so fast you could fall asleep before you have time to get into bed. Within a few weeks of using these fast-acting drugs – or any fast-acting sleeping pill – you could become addicted and experience severe withdrawal symptoms when you stop taking them.
Certain sleeping pills, such as Rohypnol and Dormicum, cause such severe memory loss they’re abused as date rape drugs. If you’ve been using sleeping tablets for weeks you shouldn’t go cold turkey if you want to stop. Wean yourself off the tablets gradually with your doctor’s help.
Sleeping tablets such as Stilnox, which are not benzodiazepams, are used just to help you fall asleep. You’re less likely to become dependent on this type.
Do any other products work?
The popular herbal remedy Valerian has a calming effect but its side effects aren’t well researched. Pregnant women, children and people with liver problems should preferably avoid it.
It should also not be used in combination with other medications that make you drowsy. There is anecdotal evidence that avenasativa (wild oats), lavender and chamomile also help.
Nytol contains an antihistamine that relaxes you. It shouldn’t be given to babies, children or pregnant women or be taken in combination with other medications that make you drowsy.
Compiled by Mari Hudson and Elise-Marie Tancred.
(Health24, updated January 2012)