REM sleep
The first rapid eye movement (REM) period usually begins about 70 to 90 minutes
after we fall asleep. We have around three to five REM episodes a night.
Although we are not conscious, the brain is very active - often more so than when we
are awake. This is the period when most dreams occur. Our eyes dart around (hence
the name), our breathing rate and blood pressure rise. However, our bodies are
effectively paralysed, said to be nature's way of preventing us from acting out our
dreams.
After REM sleep, the whole cycle begins again.
How much sleep is required?
There is no set amount of time that everyone needs to sleep, since it varies from
person to person. Results from the sleep profiler indicate that people like to sleep
anywhere between 5 and 11 hours, with the average being 7.75 hours.
Jim Horne from Loughborough University's Sleep Research Centre has a simple
answer though: "The amount of sleep we require is what we need not to be sleepy in
the daytime.