How much sleep do YOU need? Take the test to find out,
It’s often hard to know exactly how much sleep you should be getting.
Experts claim most healthy adults need seven to nine hours per night – but this is hardly exact, and it also depends on age and individual needs.
Thankfully, a free online tool now tells if you’re getting enough slumber.
The sleep calculator, from non-profit organisation the Sleep Foundation, works out your optimum bedtime based on your details.
It asks just two questions to ensure a decent amount of shut-eye each time – and it doesn’t want your name or email address.
The personalized results are ‘based on your unique biology and lifestyle preferences’ and help prevent sleep deprivation.
According to experts at the Sleep Foundation, sleep deprivation has ‘short and long term impacts on physical, emotional and cognitive health’.
They say: ‘The quality of your sleep impacts core metabolic functions like immunity, cardiovascular health, and cognition.’
To use the sleep calculator, you simply need to enter your age range – anything from a few months old to 65 and over (if you’re a parent you can try this on behalf of a baby).
Age is a crucial bit of data here because the recommended amount of sleep each night largely depends on your age.
The sleep calculator also asks you to choose your preferred sleep schedule.
To do this you have to select either ‘I want to wake up at…’ or ‘I want to go to bed at…’ followed by a time.
Once you enter your details, hit the blue button marked ‘Calculate’.
After a second or two, the calculator gives you a recommended bedtime based on the relevant information.
For example, if you tell the tool you’re 26 to 35 years old and want to wake up at 8am, the tool tells you to go to bed at 10:45pm for optimum refreshment.
That’s a total of nine hours and 15 minutes in bed!
It also gives you an additional second option if you want one fewer ‘sleep cycles’ during your nightly slumber.
The sleep cycle is the natural oscillation between the slow-wave and REM phases of sleep, and each one usually takes 80 to 100 minutes.
More sleep cycles per night is generally associated with greater physical and mental restoration.
The sleep calculator offers a ‘personalized tool for sleep’ than ‘ensures your schedule allows ample time for rest’, according to The Sleep Foundation.
It says: ‘These sleep recommendations provide an overview of how much sleep most people need, but the exact amount of sleep a specific person should get depends on other factors, such as their overall health.
‘A doctor is in the best position to make a detailed sleep recommendation for any individual based on their unique situation.’
Generally, experts recommend adults sleep between seven and nine hours a night – and adults who sleep under seven hours are more at risk of health issues.
Teenagers (13-18 years old) need eight to 10 hours per night, while children aged 6-12 years old need a whopping nine to 12 hours per night, according to the NHS.
The recommended amount of sleep continues to increase the younger someone is – 10 to 13 hours for 3-5 five year olds, 11 to 14 hours for 1-2 year olds, and 12 to 16 hours for babies aged 4-12 months (these figures include naps).
Meanwhile, newborn babies (aged 0-4 months) need eight to 18 hours including naps.
Additional sleep for children and teens supports their developing brain, as well as physical growth spurts.
According to a survey last year, the average Brit gets just six hours and 20 minutes of sleep a night.
THE FOUR STAGES OF SLEEP
Sleep is generally separated in four stages. The first three of these are known as ‘non rapid eye movement’ or NREM sleep.
The last stage is known as rapid eye movement or REM sleep.
A typical night’s sleep goes back and forth between the stages.
Stage 1: In the first five minutes or so after dropping off we are not deeply asleep.
We are still aware of our surroundings but our muscles start to relax, the heart beat slows down and brainwave patterns, known as theta waves, become irregular but rapid.
Although we are asleep during Stage 1, we may wake up from it feeling like we didn’t sleep at all.
After around five minutes our bodies move into stage two.
Stage 2: This is when we have drifted into sleep, and if awakened would know you we been asleep. Waking up is still fairly easy.
This stage is identified by short bursts of electrical activity in the brain known as spindles, and larger waves known as K-complexes, which indicate that the brain is still aware of what is going on around it before turning off to a sub-conscious level.
Heartbeat and breathing is slow, and muscles relax even further.
Our body temperature drops and eye movements stop.
Brain wave activity slows but is marked by brief bursts of electrical activity.
Stage 3: Stage 3 non-REM sleep is the period of deep sleep that we need to feel refreshed in the morning.
It occurs in longer periods during the first half of the night.
Our heartbeat and breathing slow to their lowest levels during sleep and brain waves become even slower.
Our muscles are relaxed and it people may find it difficult to awaken us.
The body repairs muscles and tissues, stimulates growth and development, boosts immune function, and builds up energy for the next day.
Hypnagogia – the transitional state between wakefulness and sleep – is associated with NREM stages one to three.
Mental phenomena during hypnagogia include lucid thought, lucid dreaming, hallucinations and sleep paralysis.
REM sleep: REM sleep first occurs about 90 minutes after falling asleep.
Our eyes move rapidly from side to side behind closed eyelids.
Mixed frequency brain wave activity becomes closer to that seen in wakefulness.
Our breathing becomes faster and irregular, and heart rate and blood pressure increase to near waking levels.
Most dreaming occurs during REM sleep, although some can also occur in non-REM sleep.
Arm and leg muscles become temporarily paralysed, which prevents us from acting out our dreams.
As we age, we spend less of our time in REM sleep.
Memory consolidation most likely requires both non-REM and REM sleep.
Source: US National Institutes of Health
