1. What happens to our brains when we fall asleep? 2. What are the two main states of sleep called? 3. How much sleep do we need at different stages of our lives? 4. What is a cluе that someone may be suffering from sleep apnoea?

1 When we fall asleep, our brain goes into "low energy" mode

2 sleep is divided into two main states: non-REM and REM

3 A newborn baby will sleep up to 19 hours a day, school pupil usually needs around 11 hours sleep,teenagers needs up to ten hours and adult generally needs around eight hours a night.

4. narcolepsy is a condition where a person can become incredibly sleepy with very little warning