The science of sleep, p.16
The Science of Sleep, page 16
Cancer
Higher risk of developing a benign tumour of the colon and rectum which can lead to colon cancer
Bone density
Short sleep carries an increased risk of osteoporosis in post-menopausal women
When sleep goes wrong | Can chronic sleep deprivation harm my overall health?
AM I SLEEP-DEPRIVED?
Look out for any warning signs that you may need to increase your regular quota of sleep.
• Physical symptoms include tension headaches, jaw-clenching or teeth-grinding, irritable bowel syndrome, high blood pressure, or sexual dysfunction.
• Psychological impact may be irritability, impatience, memory lapses, and poor performance, as well as anxiety and depression.
g When sleep goes wrong g CONTENTS
I’ve always had sleep issues. What’s wrong with me?
Consistently struggling to get to or stay asleep, or waking too early are the classic hallmarks of insomnia – a sleep disorder with far-reaching effects.
Anyone who has experienced insomnia knows all too well the knock-on effects it can have on daily life: daytime drowsiness, irritability, poor memory, fatigue, and difficulties in relationships can all follow on from this condition. Studies have indicated that insomnia affects approximately 10%–30% of the population worldwide, with rates as high as 60% in some countries. Women and older people seem to be particularly susceptible.
WHAT CAUSES INSOMNIA?
A combination of psychological, behavioural, environmental, and biological components are all thought to play their part in the onset and continuance of insomnia. Some people have a higher risk of developing insomnia: among the predisposing factors are anxiety, depression, some prescription medications, chronic stress, or some of the hormonal changes that come with age. Studies have also shown that genetics play a part, and insomnia often runs in families.
Specific life events can also disrupt sleep and trigger a bout of insomnia, such as the stress of a new job, as well as changes to schedules caused by shift work or jet lag. A few bad nights of sleep here and there is normal, and acute, or short-term, insomnia often disappears once the stressful event passes or we adapt to it. However, for some people, insomnia can become chronic, or long-term. Once someone has had difficulty sleeping for more than four weeks, they have usually begun to think about sleep differently, acting in ways that perpetuate the issue. Behaviours that contribute to insomnia continuing include caffeine, alcohol, or nicotine use; inconsistent bedtimes; and too much time spent browsing social media in bed.
INSOMNIA IS A HUNGRY BEAST
When insomnia strikes, changing your bedtime habits, developing relaxation strategies, and practising good sleep hygiene are vital. Early intervention in these areas can often be enough to stop insomnia becoming chronic. It’s also important to remind yourself that a bout of acute insomnia is perfectly normal: insomnia is fed by fear, so the more you worry about not being able to sleep, the worse it is likely to get. CBTI is one of the most effective techniques for helping you to rethink things, and address your bad habits and negative thoughts around sleep. By doing so, you can learn to nurture the mental and physical conditions necessary for a good night’s sleep.
Insomnia progression
This graphic shows that insomnia usually begins with a triggering event. Sometimes there are latent risk factors before the onset, too. To cope with the stressful trigger, you may develop unhelpful behaviours that actually maintain insomnia. If these behaviours become ingrained, they can mean chronic insomnia develops.
n Double-tap image to read the labels
Before
Underlying risk factors, like having anxiety, make it more likely insomnia will develop
Insomnia onset
A stressful trigger such as a death in the family means insomnia threshold is reached
Acute insomnia
You begin to behave in unhelpful ways that perpetuate insomnia, for example too much caffeine
Chronic insomnia
If unhelpful behaviours are not addressed, even if initial stressor passes, insomnia becomes chronic
g When sleep goes wrong g CONTENTS
Does lack of sleep impair judgement?
We’re often advised to sleep on a big decision, and science bears out this piece of folk wisdom.
Our sleep has a profound effect on the way we process information. Because the brain is so complex and interconnected this is a difficult area to research, and scientific findings vary – as do individual sleep needs. Research shows that going for only 17 hours without sleep can impair cognitive performance (including reaction time) nearly as much as being at some countries’ legal alcohol limit for driving.
Neuroscientists do know that insufficient sleep has a particular impact on the brain’s prefrontal cortex, the area that enables us to problem solve, reason, organize, plan, and perform other higher cognitive tasks. The medial prefrontal cortex, which also acts to regulate emotions, may be less able to “talk down” the amygdala, which processes feelings (especially fear), reacts to stress, and triggers the body’s “fight-or-flight” stress response.
Sufficient sleep is essential for efficient storage of the information that may help you make decisions: the brain consolidates different types of learned information into memories during the different stages and cycles of sleep. Sleep loss may also hamper cognitive flexibility – the ability to rapidly adjust to new information or changing events. Not only does poor sleep impair your thought processes, but there’s evidence that it also prevents you from recognizing that your thinking might be impaired. One study found sleep-deprived participants tended to claim that they were still functioning well – even when tests showed their cognitive abilities had significantly declined.
The sleep-deprived brain
A variety of brain regions play a part in decision making and communication – all need good sleep to function optimally.
n Double-tap image to read the labels
Prefrontal cortex: Controls logical thinking. Poor sleep can lead to unnecessary risk-taking
Parietal cortex: Scientists think that this multitasking area is called on to assist other areas when we are sleepy, affecting its efficiency
Amygdala: The emotional centre of the brain becomes more active and less stable following sleeplessness
Hippocampus: Sleep is essential to the memory-processing region as it performs some key tasks during sleep only
THE MORNING AFTER
In daily life, the cognitive consequences of a poor night’s sleep will usually only cause us minor irritation. Sometimes, however, lives depend on sharp and accurate judgement; the US space shuttle Challenger fell to earth after a post-launch explosion, killing its crew. An official report found some key managers got less than two hours’ sleep the night before, and sleep loss and early morning shift work contributed to some poor decisions.
Misreading the signs
Sleep-deprived people tend to see the world in a more negative light. In one study, participants were shown a series of images of people with different expressions. Sleep-deprived individuals consistently attributed more negative emotions to the faces than well-rested participants.
n Double-tap image to read the labels
Well-rested people interpreted the expression correctly
Participants were asked to judge the mood of the person in an image
Sleep-deprived people interpreted the expression wrongly
g When sleep goes wrong g CONTENTS
What’s the minimum amount of sleep I need to function well?
The base amount of sleep you need is personal to you and will depend on a variety of factors including your age, health, activity, and stress levels.
As a general guide, adults require between seven and nine hours’ sleep a night for the brain and body to perform all the necessary biological tasks that can only happen during sleep. Just a few nights of four hours’ sleep has been shown to negatively affect heart rate, blood pressure, mood, and memory – although effects are reversed when you start sleeping normally again. Although many people report that they function well on five or six hours’ sleep a night, that fact is that most will be chronically sleep-deprived.
AM I A TRUE SHORT SLEEPER?
A few people – thought to be less than 1 per cent globally – are naturally able to thrive on less sleep due to a quirk in their genetic code. A gene mutation, named DEC2, appears to work by making it easier for the body to produce more orexin, which wakes us up and keeps us alert. Studies show that people with this mutation are able to sleep for around six hours with no impact on their daytime performance. Research also found that the family members of short sleepers had another rare genetic mutation called ADRB1, which affects their sleep/wake cycle.
Although there is no widely available test to confirm if you are genetically a short sleeper, if you tend to be highly active and efficient, feel well rested in the morning, and have relatives with similar traits, it could be that you are a member of this exclusive club.
Science of staying awake
Since the discovery of the first “short-sleep gene” in 2009, researchers have identified two further mutations that may also enable natural short sleep.
CAN I SLEEP TOO MUCH?
Around 2 per cent of people are affected by “hypersomnia” – they may need as much as 10–12 hours’ sleep every night and still feel sleepy and nap in daytime. This excessive sleeping has many different causes, some of which are genetic; it can also be a side-effect of prescription medication or a symptom of depression. Specific sleep disorders that shorten or disrupt night-time sleep may also prompt sufferers to spend extra daytime hours in bed to compensate.
While research findings vary, there is some evidence that habitual oversleeping may be as detrimental to health as too little sleep. Studies have found that both can be associated with a higher risk of developing certain conditions (see below).
Too little sleep:
Reduced reasoning skills
Higher risk of obesity due to hunger and overeating
Higher risk of heart disease and strokes
Possible risk factor for dementia
less than 6
hours’ sleep
Ideal amount of sleep
Many scientific studies have identified seven to nine hours’ sleep as the optimum length of sleep to maintain physical and mental health in the vast majority of adults
7–9
hours’ sleep
Too much sleep:
Reduced reasoning ability
Links to faster cognitive decline
Higher risk of heart disease and strokes
Possible early warning sign of dementia
more than 9
hours’ sleep
g When sleep goes wrong g CONTENTS
What are microsleeps?
Sitting in a long, boring meeting, your head suddenly lolls to one side and you jerk back to reality. This is a microsleep – a brief, involuntary bout of unconsciousness.
You may not even be aware of a microsleep, but under research conditions, your brainwave activity would clearly indicate that you were asleep with your senses switched off and unresponsive to the world around you. Microsleeps don’t always mean we close our eyes – so if you’ve seen someone’s eyes glaze over and they start to look zoned out, they could well be having a microsleep in front of you.
WHAT CAUSES MICROSLEEPS?
When we are fully rested, the pressure to sleep is low for most of the day and our “sleep switch” stays off. However, when we have not had sufficient sleep, that pressure stays high and can peak at any time. As soon as the body senses a slowing-down (for instance, when we zone out in that tedious meeting), it seizes the opportunity, flicks the sleep switch, and it’s lights out for a moment.
Sleep deprivation is the main cause of microsleeps, with shift workers, especially those with changeable shift patterns, such as medical professionals, most at risk. Sleep disorders that disrupt sleep, such as narcolepsy or sleep apnoea, can also be a factor.
The only way to eliminate microsleeps is to tackle the cause of your sleep deprivation. When that’s not possible, for instance when you have a newborn baby, try to claw back sleep whenever you can (such as napping whenever your baby does) and be assured that you will weather this temporary sleep drought without long-term harm to your health.
g When sleep goes wrong g CONTENTS
How dangerous is driving when I’m tired?
Have you ever felt your eyes starting to close when driving? If so, you are not alone. Drowsy driving is surprisingly common, and a major cause of accidents.
Drive when you are drowsy and the impact on your performance is similar to being under the influence of drugs or alcohol: your judgement is impaired, reactions are slower, and you can even fail to spot hazards. Driving drowsy also increases your risk of falling into a microsleep at the wheel, especially when you’re on a long, monotonous drive. Even the briefest loss of consciousness can be catastrophic so the advice is simple: never drive when you’re tired.
n Double-tap image to read the labels
ARE YOU AT RISK?
You are most at risk of drowsy driving if you are currently suffering from chronic sleep deprivation or sleep apnoea; a shift worker; or driving at night. However, just one night of disrupted sleep can impact your alertness. If you’re tired, think carefully before you get behind the wheel – opening the windows or turning up the music is not going to counter that irresistible urge to close your eyes. Stop driving as soon as you can if you experience any of the following:
• Yawning
• Heavy eyelids
• Difficulty concentrating
• Missing a turning
• Drifting across lanes or hitting a rumble strip
Don’t start driving again until you’ve had a proper rest (see box). No matter how inconvenient it may be to break your journey, there’s no alternative. Driving drowsy is risking your own and everyone else’s safety.
When sleep goes wrong | How dangerous is driving when I’m tired?
Caffeine-kick driving hack
The best temporary fix for fatigue is a cup of strong coffee, followed by a 30-minute nap. The caffeine in coffee takes around 30 minutes to kick in, so will reach its full power just as you wake.
g When sleep goes wrong g CONTENTS
If I don’t get enough sleep, will I get Alzheimer’s disease?
Growing evidence suggests that sleep can protect against Alzheimer’s disease and dementia, but shouty headlines proclaiming that a bad night’s sleep causes Alzheimer’s have fuelled widespread anxiety.
The study that triggered the headlines identified the role of a protein called beta-amyloid in neurodegeneration – the progressive loss of function of nerve cells. Beta-amyloid builds up naturally in the brain, but is found in abnormally large amounts in those with Alzheimer’s. When beta-amyloid accumulates, it forms clumps, known as plaques, that disrupt the nutrient supply to brain cells. This kills the cells and in turn causes neurodegeneration and destroys memory. This study found that those who experienced a night of sleep deprivation had slightly higher than normal levels of beta-amyloid, leading the researchers to suggest a possible link between poor sleep and Alzheimer’s.
A PROTEIN CALLED TAU
More recent research has shown that tau, another protein found in brain neurons, may play a more significant role in the relationship between sleep and Alzheimer’s. Abnormal tau clusters, known as tangles, have been found in the brains of Alzheimer’s patients, and sleep deprivation appears to cause tau to increase. This is likely to be because during Stage-3 deep sleep, the brain prompts the release of cerebrospinal fluid (CSF). CSF is thought to help flush toxins through the brain’s glymphatic system – including beta-amyloid and tau – and disrupted sleep may therefore mean missing out on this vital clearance process. It isn’t yet clear whether simply having high levels of beta-amyloid or tau increases the risk of Alzheimer’s onset – research is ongoing – but what we do know is that poor sleep is likely to be only one piece in solving the Alzheimer’s puzzle.
Poor sleep = Alzheimer’s?
Sleep is only one of the many factors that determine an individual’s risk of developing Alzheimer’s disease – onset seems to be triggered by a complex interplay between biological and environmental factors.
n Double-tap image to read the labels
Sleep deprivation Lack of Stage-3 sleep may lead to a build up of beta-amyloid and tau in the brain
When sleep goes wrong | If I don’t get enough sleep, will I get Alzheimer’s disease?
TOO SOON TO TELL
• Even if you are regularly sleep-deprived, there’s still no clear evidence that you are more at risk of developing Alzheimer’s. Of course, sleeping well will certainly boost overall health and help both body and brain manage the ageing process.
• The link between sleep and Alzheimer’s is being intensively researched. Large-scale studies could soon tell us whether finding ways to increase Stage-3, deep, slow-wave sleep could reduce the risk of neurodegeneration.
g When sleep goes wrong g CONTENTS
What’s the impact of long-term stress on sleep?
“Stress” means different things to different people, but biologically, it’s a specific physiological response that puts our systems on high alert.
Higher risk of developing a benign tumour of the colon and rectum which can lead to colon cancer
Bone density
Short sleep carries an increased risk of osteoporosis in post-menopausal women
When sleep goes wrong | Can chronic sleep deprivation harm my overall health?
AM I SLEEP-DEPRIVED?
Look out for any warning signs that you may need to increase your regular quota of sleep.
• Physical symptoms include tension headaches, jaw-clenching or teeth-grinding, irritable bowel syndrome, high blood pressure, or sexual dysfunction.
• Psychological impact may be irritability, impatience, memory lapses, and poor performance, as well as anxiety and depression.
g When sleep goes wrong g CONTENTS
I’ve always had sleep issues. What’s wrong with me?
Consistently struggling to get to or stay asleep, or waking too early are the classic hallmarks of insomnia – a sleep disorder with far-reaching effects.
Anyone who has experienced insomnia knows all too well the knock-on effects it can have on daily life: daytime drowsiness, irritability, poor memory, fatigue, and difficulties in relationships can all follow on from this condition. Studies have indicated that insomnia affects approximately 10%–30% of the population worldwide, with rates as high as 60% in some countries. Women and older people seem to be particularly susceptible.
WHAT CAUSES INSOMNIA?
A combination of psychological, behavioural, environmental, and biological components are all thought to play their part in the onset and continuance of insomnia. Some people have a higher risk of developing insomnia: among the predisposing factors are anxiety, depression, some prescription medications, chronic stress, or some of the hormonal changes that come with age. Studies have also shown that genetics play a part, and insomnia often runs in families.
Specific life events can also disrupt sleep and trigger a bout of insomnia, such as the stress of a new job, as well as changes to schedules caused by shift work or jet lag. A few bad nights of sleep here and there is normal, and acute, or short-term, insomnia often disappears once the stressful event passes or we adapt to it. However, for some people, insomnia can become chronic, or long-term. Once someone has had difficulty sleeping for more than four weeks, they have usually begun to think about sleep differently, acting in ways that perpetuate the issue. Behaviours that contribute to insomnia continuing include caffeine, alcohol, or nicotine use; inconsistent bedtimes; and too much time spent browsing social media in bed.
INSOMNIA IS A HUNGRY BEAST
When insomnia strikes, changing your bedtime habits, developing relaxation strategies, and practising good sleep hygiene are vital. Early intervention in these areas can often be enough to stop insomnia becoming chronic. It’s also important to remind yourself that a bout of acute insomnia is perfectly normal: insomnia is fed by fear, so the more you worry about not being able to sleep, the worse it is likely to get. CBTI is one of the most effective techniques for helping you to rethink things, and address your bad habits and negative thoughts around sleep. By doing so, you can learn to nurture the mental and physical conditions necessary for a good night’s sleep.
Insomnia progression
This graphic shows that insomnia usually begins with a triggering event. Sometimes there are latent risk factors before the onset, too. To cope with the stressful trigger, you may develop unhelpful behaviours that actually maintain insomnia. If these behaviours become ingrained, they can mean chronic insomnia develops.
n Double-tap image to read the labels
Before
Underlying risk factors, like having anxiety, make it more likely insomnia will develop
Insomnia onset
A stressful trigger such as a death in the family means insomnia threshold is reached
Acute insomnia
You begin to behave in unhelpful ways that perpetuate insomnia, for example too much caffeine
Chronic insomnia
If unhelpful behaviours are not addressed, even if initial stressor passes, insomnia becomes chronic
g When sleep goes wrong g CONTENTS
Does lack of sleep impair judgement?
We’re often advised to sleep on a big decision, and science bears out this piece of folk wisdom.
Our sleep has a profound effect on the way we process information. Because the brain is so complex and interconnected this is a difficult area to research, and scientific findings vary – as do individual sleep needs. Research shows that going for only 17 hours without sleep can impair cognitive performance (including reaction time) nearly as much as being at some countries’ legal alcohol limit for driving.
Neuroscientists do know that insufficient sleep has a particular impact on the brain’s prefrontal cortex, the area that enables us to problem solve, reason, organize, plan, and perform other higher cognitive tasks. The medial prefrontal cortex, which also acts to regulate emotions, may be less able to “talk down” the amygdala, which processes feelings (especially fear), reacts to stress, and triggers the body’s “fight-or-flight” stress response.
Sufficient sleep is essential for efficient storage of the information that may help you make decisions: the brain consolidates different types of learned information into memories during the different stages and cycles of sleep. Sleep loss may also hamper cognitive flexibility – the ability to rapidly adjust to new information or changing events. Not only does poor sleep impair your thought processes, but there’s evidence that it also prevents you from recognizing that your thinking might be impaired. One study found sleep-deprived participants tended to claim that they were still functioning well – even when tests showed their cognitive abilities had significantly declined.
The sleep-deprived brain
A variety of brain regions play a part in decision making and communication – all need good sleep to function optimally.
n Double-tap image to read the labels
Prefrontal cortex: Controls logical thinking. Poor sleep can lead to unnecessary risk-taking
Parietal cortex: Scientists think that this multitasking area is called on to assist other areas when we are sleepy, affecting its efficiency
Amygdala: The emotional centre of the brain becomes more active and less stable following sleeplessness
Hippocampus: Sleep is essential to the memory-processing region as it performs some key tasks during sleep only
THE MORNING AFTER
In daily life, the cognitive consequences of a poor night’s sleep will usually only cause us minor irritation. Sometimes, however, lives depend on sharp and accurate judgement; the US space shuttle Challenger fell to earth after a post-launch explosion, killing its crew. An official report found some key managers got less than two hours’ sleep the night before, and sleep loss and early morning shift work contributed to some poor decisions.
Misreading the signs
Sleep-deprived people tend to see the world in a more negative light. In one study, participants were shown a series of images of people with different expressions. Sleep-deprived individuals consistently attributed more negative emotions to the faces than well-rested participants.
n Double-tap image to read the labels
Well-rested people interpreted the expression correctly
Participants were asked to judge the mood of the person in an image
Sleep-deprived people interpreted the expression wrongly
g When sleep goes wrong g CONTENTS
What’s the minimum amount of sleep I need to function well?
The base amount of sleep you need is personal to you and will depend on a variety of factors including your age, health, activity, and stress levels.
As a general guide, adults require between seven and nine hours’ sleep a night for the brain and body to perform all the necessary biological tasks that can only happen during sleep. Just a few nights of four hours’ sleep has been shown to negatively affect heart rate, blood pressure, mood, and memory – although effects are reversed when you start sleeping normally again. Although many people report that they function well on five or six hours’ sleep a night, that fact is that most will be chronically sleep-deprived.
AM I A TRUE SHORT SLEEPER?
A few people – thought to be less than 1 per cent globally – are naturally able to thrive on less sleep due to a quirk in their genetic code. A gene mutation, named DEC2, appears to work by making it easier for the body to produce more orexin, which wakes us up and keeps us alert. Studies show that people with this mutation are able to sleep for around six hours with no impact on their daytime performance. Research also found that the family members of short sleepers had another rare genetic mutation called ADRB1, which affects their sleep/wake cycle.
Although there is no widely available test to confirm if you are genetically a short sleeper, if you tend to be highly active and efficient, feel well rested in the morning, and have relatives with similar traits, it could be that you are a member of this exclusive club.
Science of staying awake
Since the discovery of the first “short-sleep gene” in 2009, researchers have identified two further mutations that may also enable natural short sleep.
CAN I SLEEP TOO MUCH?
Around 2 per cent of people are affected by “hypersomnia” – they may need as much as 10–12 hours’ sleep every night and still feel sleepy and nap in daytime. This excessive sleeping has many different causes, some of which are genetic; it can also be a side-effect of prescription medication or a symptom of depression. Specific sleep disorders that shorten or disrupt night-time sleep may also prompt sufferers to spend extra daytime hours in bed to compensate.
While research findings vary, there is some evidence that habitual oversleeping may be as detrimental to health as too little sleep. Studies have found that both can be associated with a higher risk of developing certain conditions (see below).
Too little sleep:
Reduced reasoning skills
Higher risk of obesity due to hunger and overeating
Higher risk of heart disease and strokes
Possible risk factor for dementia
less than 6
hours’ sleep
Ideal amount of sleep
Many scientific studies have identified seven to nine hours’ sleep as the optimum length of sleep to maintain physical and mental health in the vast majority of adults
7–9
hours’ sleep
Too much sleep:
Reduced reasoning ability
Links to faster cognitive decline
Higher risk of heart disease and strokes
Possible early warning sign of dementia
more than 9
hours’ sleep
g When sleep goes wrong g CONTENTS
What are microsleeps?
Sitting in a long, boring meeting, your head suddenly lolls to one side and you jerk back to reality. This is a microsleep – a brief, involuntary bout of unconsciousness.
You may not even be aware of a microsleep, but under research conditions, your brainwave activity would clearly indicate that you were asleep with your senses switched off and unresponsive to the world around you. Microsleeps don’t always mean we close our eyes – so if you’ve seen someone’s eyes glaze over and they start to look zoned out, they could well be having a microsleep in front of you.
WHAT CAUSES MICROSLEEPS?
When we are fully rested, the pressure to sleep is low for most of the day and our “sleep switch” stays off. However, when we have not had sufficient sleep, that pressure stays high and can peak at any time. As soon as the body senses a slowing-down (for instance, when we zone out in that tedious meeting), it seizes the opportunity, flicks the sleep switch, and it’s lights out for a moment.
Sleep deprivation is the main cause of microsleeps, with shift workers, especially those with changeable shift patterns, such as medical professionals, most at risk. Sleep disorders that disrupt sleep, such as narcolepsy or sleep apnoea, can also be a factor.
The only way to eliminate microsleeps is to tackle the cause of your sleep deprivation. When that’s not possible, for instance when you have a newborn baby, try to claw back sleep whenever you can (such as napping whenever your baby does) and be assured that you will weather this temporary sleep drought without long-term harm to your health.
g When sleep goes wrong g CONTENTS
How dangerous is driving when I’m tired?
Have you ever felt your eyes starting to close when driving? If so, you are not alone. Drowsy driving is surprisingly common, and a major cause of accidents.
Drive when you are drowsy and the impact on your performance is similar to being under the influence of drugs or alcohol: your judgement is impaired, reactions are slower, and you can even fail to spot hazards. Driving drowsy also increases your risk of falling into a microsleep at the wheel, especially when you’re on a long, monotonous drive. Even the briefest loss of consciousness can be catastrophic so the advice is simple: never drive when you’re tired.
n Double-tap image to read the labels
ARE YOU AT RISK?
You are most at risk of drowsy driving if you are currently suffering from chronic sleep deprivation or sleep apnoea; a shift worker; or driving at night. However, just one night of disrupted sleep can impact your alertness. If you’re tired, think carefully before you get behind the wheel – opening the windows or turning up the music is not going to counter that irresistible urge to close your eyes. Stop driving as soon as you can if you experience any of the following:
• Yawning
• Heavy eyelids
• Difficulty concentrating
• Missing a turning
• Drifting across lanes or hitting a rumble strip
Don’t start driving again until you’ve had a proper rest (see box). No matter how inconvenient it may be to break your journey, there’s no alternative. Driving drowsy is risking your own and everyone else’s safety.
When sleep goes wrong | How dangerous is driving when I’m tired?
Caffeine-kick driving hack
The best temporary fix for fatigue is a cup of strong coffee, followed by a 30-minute nap. The caffeine in coffee takes around 30 minutes to kick in, so will reach its full power just as you wake.
g When sleep goes wrong g CONTENTS
If I don’t get enough sleep, will I get Alzheimer’s disease?
Growing evidence suggests that sleep can protect against Alzheimer’s disease and dementia, but shouty headlines proclaiming that a bad night’s sleep causes Alzheimer’s have fuelled widespread anxiety.
The study that triggered the headlines identified the role of a protein called beta-amyloid in neurodegeneration – the progressive loss of function of nerve cells. Beta-amyloid builds up naturally in the brain, but is found in abnormally large amounts in those with Alzheimer’s. When beta-amyloid accumulates, it forms clumps, known as plaques, that disrupt the nutrient supply to brain cells. This kills the cells and in turn causes neurodegeneration and destroys memory. This study found that those who experienced a night of sleep deprivation had slightly higher than normal levels of beta-amyloid, leading the researchers to suggest a possible link between poor sleep and Alzheimer’s.
A PROTEIN CALLED TAU
More recent research has shown that tau, another protein found in brain neurons, may play a more significant role in the relationship between sleep and Alzheimer’s. Abnormal tau clusters, known as tangles, have been found in the brains of Alzheimer’s patients, and sleep deprivation appears to cause tau to increase. This is likely to be because during Stage-3 deep sleep, the brain prompts the release of cerebrospinal fluid (CSF). CSF is thought to help flush toxins through the brain’s glymphatic system – including beta-amyloid and tau – and disrupted sleep may therefore mean missing out on this vital clearance process. It isn’t yet clear whether simply having high levels of beta-amyloid or tau increases the risk of Alzheimer’s onset – research is ongoing – but what we do know is that poor sleep is likely to be only one piece in solving the Alzheimer’s puzzle.
Poor sleep = Alzheimer’s?
Sleep is only one of the many factors that determine an individual’s risk of developing Alzheimer’s disease – onset seems to be triggered by a complex interplay between biological and environmental factors.
n Double-tap image to read the labels
Sleep deprivation Lack of Stage-3 sleep may lead to a build up of beta-amyloid and tau in the brain
When sleep goes wrong | If I don’t get enough sleep, will I get Alzheimer’s disease?
TOO SOON TO TELL
• Even if you are regularly sleep-deprived, there’s still no clear evidence that you are more at risk of developing Alzheimer’s. Of course, sleeping well will certainly boost overall health and help both body and brain manage the ageing process.
• The link between sleep and Alzheimer’s is being intensively researched. Large-scale studies could soon tell us whether finding ways to increase Stage-3, deep, slow-wave sleep could reduce the risk of neurodegeneration.
g When sleep goes wrong g CONTENTS
What’s the impact of long-term stress on sleep?
“Stress” means different things to different people, but biologically, it’s a specific physiological response that puts our systems on high alert.
