Rapid Eye Movement
It is amazing that the mind and body can be refreshed after a nights sleep. Far from being a time of stillness and relaxation, sleep may take us into parts of the subconscious mind that we are unable to reach during our waking hours...
Sleep is divided into four stages and two distinct states - REM and non REM (deep sleep). The REM (rapid eye movement) state is when the eyes can be seen to move under the eyelids. It is during this state that dreaming occurs. Watch a baby or small child sleeping and the movement of the eyes under the eyelids is clear to see. These movements correspond to recognisable brain waves and EEG readings which record electrical activity in the brain, show that adults also manifest the same phenomenon.
Paradoxical SleepREM sleep is when the body and mind are most active. This will differ between individuals but there are distinct stages of REM sleep. Each stage takes the sleeper into a longer period of REM sleep and may be accompanied with a change of position as the brain and body are at their closest to normal daytime activity. The sleeper may be hard to wake as they are experiencing deep muscular relaxation. This stage is also known as 'paradoxical sleep' as the body may also show an increase in heart rate, oxygen consumption and other changes, which resemble the waking state. The sleeper is particularly vulnerable during this time as there is an increased risk of cardiac arrest and asthma attacks.
REM DeprivationResearch has shown that REM sleep is important to wellbeing. When we are deprived of REM sleep, we make up for the 'debt' by incorporating more of this stage into subsequent sleeps. Deprivation causes mood changes, fatigue and loss of concentration. Longer periods of sleep loss may result in 'daytime dreaming'. This is believed to show the psychological importance of dreams. Although the purpose of dreaming is hard to prove, it is believed that babies start to dream at around 25 weeks gestation and that this stimulates the developing brain.
REM and DreamsDuring REM sleep the eyes move beneath the closed eyelids. Research suggests that the flickering movements may be synchronised to dream activities. This sensory stimulation is restricted to the eyes preventing the possible danger of the entire body becoming involved in 'acting out' the dream event. This 'safety mechanism' may also explain why dreamers recall dreams where they experience paralysis such as the inability to scream or run away from threatening events.
The brain activity and the physical changes in body functions are of interest to researchers and psychologists who seek to understand the meaning of dreams. It has been proposed that we are dreaming all the time and it is only the more powerful stimulus of the demands of our waking lives that separates us from this realisation. Researches seek to explain the meaning and differences between the different types of dreams - the ones we remember and those that occur during the deeper stages of REM sleep.