The science of sleep, p.4
The Science of Sleep, page 4
Human growth hormone is essential for overall growth in children, and in adults it maintains strength and regulates metabolism. For both children and adults it is necessary for cell repair – particularly when recovering from exercise, injury, or illness. Growth hormone is released by the pituitary gland throughout the day, but peak levels are secreted during the deeper stages of sleep – so a lack of good sleep will reduce the overall amount of the hormone in your body.
Happily, poor sleep will have little effect on children’s growth, because the resulting hormone shortfall is compensated for by the huge surges that occur during a child’s growth spurts.
For adults, however, losing out on hormone production due to poor sleep is more of an issue. It can lead to reduced muscle mass and strength, thinning hair, and weaker bones. Although other factors may be at play, ensuring you get enough deep sleep will boost your body’s natural growth and repair functions.
Growth hormone release
This hormone is released throughout the day, but certain activities, such as eating or exercise, cause it to spike. The biggest peak occurs during deep sleep.
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Will my child grow out of night terrors?
Any parent who has witnessed their child experiencing a night terror will testify to how distressing it can be.
Night terrors are brief episodes, usually lasting up to 15 minutes, where your child might scream, sweat, appear terrified, and move around, before abruptly falling back to sleep. Different to nightmares, which happen during REM sleep and can be remembered, night terrors usually occur in the early part of the night during deep, non-REM sleep. They are not technically dreams but a sudden fear reaction driven by the fight-or-flight stress response and resulting spike in adrenaline.
Despite often having their eyes open, your child is not fully awake and will not recognize you during an episode. Because of this, waking your child from this state to comfort them can leave them more disorientated and confused, and they will take longer to settle back down.
NO CAUSE FOR ALARM
Episodes can be triggered by stress, tiredness, a change in sleep schedule, medication, or a fever, and are more likely to occur in girls than boys. Studies in twins suggest a genetic component, and there is also a link with sleepwalking – research shows that a child of two parents who are, or were, sleepwalkers is more likely to experience night terrors, and around one-third of children who have terrors develop sleepwalking as they grow older.
No matter how alarming a night terror may be for you as a parent, rest assured that they won’t do your child any lasting physical or psychological harm – children rarely remember episodes. The most common age for children to experience night terrors is 2–4 years, but they can continue until age 12; reassuringly, most children grow out of them by the time they reach their teens.
Life Stages | Will my child grow out of night terrors?
HOW TO HELP
In some children, night terrors happen at roughly the same time each night, so it can help to gently wake your child shortly before an anticipated episode. Because they have been in a deep sleep, they will likely fall asleep again very quickly. Try doing this for seven consecutive nights; this can be enough to break the pattern without affecting their overall sleep quality.
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Does the school day fit in with my teenager’s sleep needs?
Anyone with a teenager will testify to the daily struggle of waking them up for school, but is this sleepy stupor and inability to focus in the mornings simply a matter of teenage laziness, or something more?
During puberty, not only are teens experiencing a hormonal storm, but they may also be suffering from chronic sleep deprivation. It’s not that teens are inherently lazy; their tendency to drift off in mid-morning classes is partly down to them being denied their natural sleeping routine, which differs to that of children and adults.
BODY CLOCK SHIFT
When puberty hits, the circadian rhythm jumps forward by around two hours, likely due to growth- and sex-hormone surges, so production of melatonin (the sleepiness hormone) occurs later in the day. This means that expecting a teen to sleep at 11pm is like an adult being sent to bed at 8pm. And for teens, rising at 7am is as painful as if an adult were hauled out of bed at 4am.
Because they are not yet ready for sleep, many teens hang out online late into the night, further stimulating their brain and keeping them awake. This leads to “social jet lag”, with teens getting less sleep on school days, and sleeping longer on weekends, making them even less able to meet the demands of their school day.
A later school start and finish time would benefit teens, and of the schools that have tried this, all report improved grades and student engagement, as well as a drop in lateness and absences. Getting your teen’s school to try this might not be possible, but you can help lessen daytime sleepiness – see opposite page. When teens reach adulthood, the biological clock shifts back and this inbuilt time-lag gradually recedes.
Sleep later, learn better
Each graph charts a teen’s daily alertness levels. A later school start means they are alert for the whole school day, but on a typical schedule, their alertness peaks just as school ends.
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Life Stages | Does the school day fit in with my teenager’s sleep needs?
SUPPORTING A SLEEPY TEEN
• For younger teens, keep digital devices out of their room at night. If they are older, turning off the household WiFi at a set time each night shows you are willing to stick to the rules, too! Suggest alternative evening activities like reading or listening to a podcast, which are relaxing and help to keep sleep-inhibiting levels of the stress hormone cortisol down.
• Exposure to bright light in the morning and low light at night can help shift your teen’s sleep schedule back, so consider a dimmer on their bedroom light, or try using an orange or red bulb in their bedside lamp.
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How much does screen time affect my teenager’s sleep?
Technology use is on the rise among all age groups, but particularly amongst teenagers, so how concerned should parents be about the impact of digital devices on their children’s ability to sleep?
Digital devices are now commonplace in the bedroom, and sleep issues in teens are rising, so it seems logical to make a connection between the two.
However, a recent study found that children’s sleep is not significantly affected by screen time, with only a few minutes lost for every hour of screen use as measured throughout the day.
So if it’s not the amount of time spent on the screens themselves, could it be how and when teens are using screens that causes their sleep problems? Using digital devices in the evening, when natural sleepiness should kick in, means the urge to sleep is overridden by the excitement of what’s happening on screen, and this stimulation seems to be a factor in making teens more wakeful.
Perhaps the answer lies in simply telling teens to turn their screens off at a reasonable time, but anyone who has tried this will know it often leads to arguments. Teens’ body clocks run later than their parents’, and the urge to stay up late socializing online can feel irresistible. Most teens live a huge proportion of their lives online, and many struggle with FOMO, a fear of missing out, when they aren’t online and interacting with friends.
To help teens get better sleep, encourage them to get enough natural light and exercise during the day; both dramatically improve sleep. Also try being open to hearing about their worries – this way you can help them to manage these – and accept that a calm, consistent evening routine is a more effective antidote to FOMO than taking the smartphone to bed.
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“FOMO – the fear of missing out – is stressful for many teens, and often plays a significant role in their sleep problems.”
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Why does my teen randomly seem to doze off in the daytime?
Having a constantly sleepy teen is pretty normal, but when there’s enough stimulation to keep them awake and they still fall asleep, this may be a warning sign of something more serious.
Narcolepsy is a sudden and temporary loss of consciousness that can develop at any age, but usually appears in adolescence, with more than half of sufferers reporting their first symptoms as a teen.
Symptoms of this rare condition – it affects around one in 2,500 people – include fragmented sleep at night due to repeated waking. The next day, this results in excessive daytime sleepiness (EDS), leaving the sufferer likely to nod off at random times. During narcoleptic episodes, the sleeper quickly enters REM as they fall asleep and often experiences visual hallucinations.
Some people with narcolepsy may also experience a related, more dramatic condition called cataplexy – an abrupt loss of muscle control that causes them to collapse. Although a person experiencing cataplexy may appear unconscious, they are awake, but temporarily paralysed. Cataplexy is usually triggered by strong, positive emotions and associated behaviours, such as laughing, so can be particularly distressing when it occurs during what should be an enjoyable experience or activity.
WHAT CAUSES NARCOLEPSY?
Research shows that narcolepsy may be linked to a lack of hypocretins (also called orexins), the neurotransmitters involved in the regulation of the normal sleep/wake cycle. This deficiency appears to cause the sleep/wake “switch” to flick on and off during the day. Research is ongoing, but factors such as age, genetics, and certain infections and illnesses all seem to play a part in triggering the condition.
Life Stages | Why does my teen randomly seem to doze off in the daytime?
SEEK HELP
If you suspect your teen might be suffering from narcolepsy, it’s essential to seek support from your doctor. Narcolepsy is a lifelong condition, which can be well managed with the right medication and good sleep hygiene.
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How can I help my teen sleep better at exam time?
Teenagers and exams can be a toxic combination: anxieties around performance coupled with disruption to their body clock can all lead to sleep deprivation.
We know that a teen’s circadian rhythm shifts forward during adolescence (see The quantity of sleep we need), meaning they don’t feel sleepy until later in the evening, and need to sleep longer into the morning. A rigid timetable of exams makes no allowance for this, making it impossible for them to get enough sleep for effective learning and memory consolidation. That’s why staying up all night to cram for a test is counterproductive, and likely to lead to a cycle of sleep deprivation and sleep debt.
At exam times, it’s more important than ever to encourage your teen to stick to healthy sleep hygiene habits. They can also benefit from your help to set up a study routine. A daytime nap between study periods will help to counter the sleep debt from all those early wake-ups on exam days.
Nap-assisted learning
By studying in the morning, napping, then working again in the afternoon and evening, teens will get the sleep they need to alleviate the effects of an early wake-up call on exam day. A long nap plus six hours’ sleep at night will result in seven and a half hours sleep overall.
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Does sleep affect our ability to learn?
The brain needs sleep in order to effectively process and store information it has acquired throughout the day. During sleep it actively consolidates and creates memories to be retrieved in the future.
Sleep helps you to both remember and forget: while you sleep, the brain sifts through everything you have heard and seen that day, storing only those memories it considers to be useful or important. It’s as if once you drop off, an army of filing clerks gets to work, moving what you need to remember from short-term to long-term memory, then ditching the rest.
SLEEP CONSOLIDATES MEMORY
Research into sleep and learning indicates that the declarative memory, which stores facts and events, is reinforced by slow-wave sleep, which you get more of in the first half of the night. Procedural memory, which helps us perform tasks without having to think about them (such as riding a bike), however, is consolidated by REM sleep, most of which happens later in the night.
Interestingly, recent research has also highlighted the importance of sleep spindles, bursts of brain activity that occur in Stage-2 sleep, in transferring memories into long-term storage. The length of time we spend in Stage-2 sleep increases over the course of the night, so this may be another reason why the overall length of your sleep affects learning ability.
Exactly how sleep aids learning is a complex area that needs further research, but given that different stages of sleep seem to facilitate different types of memory, ensuring that you get enough sleep to cycle through all the stages is an excellent way to help embed learning and memories.
Making memories
When we sleep, our brain assesses everything we have learned that day and decides whether or not to transfer it to our long-term memory – from where it can later be retrieved and recalled.
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Life Stages | Does sleep affect our ability to learn?
SLEEP AND FORGETTING
As we age, the quality of slow-wave sleep decreases, and this appears to have a direct connection to brain deterioration and memory loss. Research is ongoing into whether good sleep can help protect against dementia and Alzheimer’s.
Life Stages | Does sleep affect our ability to learn?
TIPS TO BOOST LEARNING
Go to sleep within three hours of learning something new – studies have shown that this improves memory retention.
When you wake up, review what you’ve learnt the day before. This reactivates the memory and helps to consolidate new information.
Prioritize sleep. Studies have shown that getting more than six hours of sleep at night boosts memory and alertness by 25 per cent.
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How will being pregnant affect my sleep?
Each stage of pregnancy brings its own sleep challenges – so finding ways to get good-quality rest is vital.
During pregnancy, you need more sleep to support your body as it works hard to promote your baby’s growth and development, but the changes in your body can make getting good sleep more of a challenge.
FIRST TRIMESTER (WEEKS 1–12)
In your first three months, high levels of oestrogen, progesterone, and human chorionic gonadotropin – the hormones that surge in order to maintain a pregnancy – have a warming effect on the body. They can also make you sleepier than usual. Increased oestrogen may cause breast tenderness, and morning sickness (which isn’t restricted to the morning!) can also disrupt sleep. During this trimester, trying not to overheat is the priority. Keep your bedroom cool and use light bedding and nightclothes. A cotton bra with loose support can help to reduce the discomfort of tender breasts as you shift positions in bed.
SECOND TRIMESTER (WEEKS 13–28)
Insomnia can be an issue, as well as snoring and sleep apnoea, which may be triggered by weight gain and raised oestrogen levels. As the baby grows, it starts to squash up your body’s organs, which can lead to heartburn and more frequent trips to the toilet. Once the baby starts to move, a kick to your ribs in the night will definitely wake you up! Sleeping on your left side can minimize heartburn and snoring, and also boosts blood circulation, helping nutrients to reach the placenta. If you have trouble getting to sleep, lavender essential oil has clinically proven sleep-inducing qualities. Use in a room diffuser or mix a few drops with water and spray your pillow before bed.
THIRD TRIMESTER (WEEKS 29–40)
The final trimester is likely to be when your sleep is most disrupted. Your radically changed body shape means that backache, heartburn, restless legs, and swollen ankles may develop. As your bladder is compressed further, frequent toilet visits are inevitable. Extra pillows or cushions will offer support as you try to find a comfortable position. “Pregnancy pillows” are extra long and designed to support the whole length of the body – many people find them helpful in the later stages. Most of the issues causing poor sleep will disappear once the baby is born, but if you continue to experience symptoms such as restless legs, insomnia, or snoring, do seek your doctor’s advice.
Optimal sleep positions
As your bump grows, it’s most likely that sleeping on your side will be most comfortable. A pillow between your legs helps keep the spine aligned, avoiding back pain.
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Life Stages | How will being pregnant affect my sleep?
TAKE A NAP
If possible, grab every opportunity for a nap when you’re pregnant. As your night-time sleep may be more fractured, catching up during the day will help you feel rested and more energetic. Research also shows that napping may offer effective protection from developing chronic sleep issues in pregnancy.
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