What's covered
Key facts
Effects of sleep loss
Lack of sleep makes it harder to concentrate and pay attention.
Sleep and screens
Phones, tablets and other screens give off blue light, which is the type of light that makes you feel alert.
Stages of sleep and dreams
One full sleep cycle lasts about 90 minutes and repeats through the night.
The body clock
The body clock runs on a cycle of about 24 hours, roughly one day.
Why we sleep
During sleep the body repairs tissues, muscles and cells that were used during the day.
Effects of sleep loss
A tired brain finds it harder to take in and learn new information.
Sleep and screens
Darkness in the evening normally tells the brain to release melatonin a couple of hours before sleep.
Stages of sleep and dreams
Most people go through about four to six sleep cycles each night.
The body clock
The body clock is your body's own internal clock that controls when you feel sleepy and awake.
Why we sleep
Growth hormone, which helps your body grow and repair itself, is mostly released during deep sleep.
Practice questions with answers
A taste of the 44 questions in this topic, answers marked. Sign up to practise the full set with spaced repetition.
About how many hours of sleep do teenagers need each night?
- •11 to 12 hours
- •4 to 5 hours
- •6 to 7 hours
- ✓8 to 10 hours
Which hormone makes you feel sleepy and helps your body get ready for bed?
- •Adrenaline
- •Dopamine
- •Insulin
- ✓Melatonin
What do the letters REM in REM sleep stand for?
- •Rapid energy mode
- ✓Rapid eye movement
- •Rested every morning
- •Resting eye movement
About how long is one full cycle of the body clock?
- •About 12 hours
- ✓About 24 hours
- •About 48 hours
- •About 8 hours
What is one important job your brain does while you sleep?
- •Digesting food
- •Growing taller
- •Pumping blood
- ✓Storing memories
What does a lack of sleep make harder to do in lessons?
- •Breathe air
- ✓Concentrate
- •Hear sounds
- •Stand upright
Three minutes a day. Knowledge that sticks.
Practise all 44 Sleep and the body clock questions with spaced repetition, so what you revise today is still there in the exam. Free to use, no card needed.
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