REM Sleep: Most dreams occur during the REM stage. The EEG reveals brain wave patterns that are very similar to beta waves when a person is awake, active and alert. For this reason, REM sleep has been called 'paradoxical sleep'.
It is also characterised by jerky movements of the eyes beneath the eyelids, hence the label, rapid eye movement. The person's heart rate also increases, their blood pressure rises and their breathing becomes faster and more irregular. Luckily for others, our muscles are paralysed, preventing us from acting out our dreams.
Sleep Deprivation: Sleep deprivation may result in irritability, tiredness, confusion, lack of concentration, headaches, hallucinations and lack of energy.
Research has found that individuals who have been deprived of sleep are more able to concentrate on complex tasks than on simple tasks. People do not need to sleep the same number of hours which they lost to recover from sleep deprivation.
When research subjects are constantly awoken when in REM sleep and are deprived of REM sleep over successive nights, they appear more tense, irritable and more anxious than subjects deprived of the same amount of sleep but not REM sleep. Lack of REM sleep appears to affect our ability to concentrate and remember. When allowed to sleep uninterrupted, subjects experience REM rebound. That is, they spend twice as much time in REM sleep as normal to make up for the REM sleep lost. This indicates that REM sleep is vital for our survival.