The importance of sleep
Sleep is an important function to us as human beings just as breathing and eating; and is also essential for good mental health. It is vital for the maintainance of the mind not just the body and the amount needed can vary from person to person. For example, babies need many more hours than a working adult yet an elderly person may require very little sleep yet feel refreshed. Sleep allows the brain to regenerate, refresh and enables us to process information andreinforce memories which inturn prepares us for the day ahead and how well we function during that day (1).
We all know how easy or difficult our daily routine can feel when we have had a good nights sleep in comparison to having a poor nights sleep; especially if we have had poor sleep for afew nights running. It can affect our hunger, ability to concentrate, enthusiasm to talk to others, motivation to get tasks completed and our mood.
Sleep is made up of complex stages that science is still researching. Sleep is basically made up of non-rapid eye movement (non-REM) sleep and rapid eye movement (REM) sleep.
Non REM sleep (2)
Consists of four levels of sleep, each with differing depths of sleep and activity happening within the body. It is from the deepest level of this type of sleep, that we pass into REM sleep.
REM sleep (2)
In this stage, our muscles are paralyzed and a significant amount of brain activity takes place. It is in this stage that we dream. The reason for us having dreams is still unclear. Some feel that they serve no purpose whilst others feel that they attempt to process information ( which may consist of pressures/issues we have going on in our lives) and are essential for emotional and mental wellbeing.
We do know that excessive dreaming and increased REM sleep are closely assoicated with depression and it is thought too much REM sleep can increase our vulnerability to developing depression (3).
Many antidepressants are known to reduce REM sleep which maybe why they have the potential to improve somebody who is feeling depressed. (4).
(1) Payne JD & Kensinger EA (2010), Sleep’s Role in the Consolidation of Emotional Episodic Memories. Current Directions in Psychological Science 19 (5) 290-295.
(2) Mental Health Foundation: Sleep Matters: The Impact Of Sleep On Health And Wellbeing. January 2011
(3) Knutsson A, Åkerstedt T, Jonsson BG & Orth-Gomer K (1986) Increased risk of ischaemic heart disease in shift workers. Lancet 2 (8498) 89–92.
(4) Dunleavy DL, Brezinova V, Oswald I, Maclean AW & Tinker M (1972) Changes during weeks in effects of tricyclic drugs on the human sleeping brain. British Journal of Psychiatry 120 663-672.