|
Below, you'll find extensive information on leading
what caused the great depression articles and products to help you on your way
to success.
Stages Of Sleep And Dreams
By Richard Waller, Sat Dec 10th
/p> When it comes to sleep, the longer you stay awake, the longeryou sleep. The amount of sleep a person needs is determined bythe Circadian system or the body's internal clock. Reduction inblood pressure and heart rate are two processes that sleepinduces. The two basic distinctions that apply to sleep are NREM ornon-rapid eye movement and REM or rapid eye movement. In theduration of one night they occur as a 90-minute cycle, repeatingup to six times for the duration of the night in all four stagesof NREM and REM. REM results from NREM. Sleep Cycle
Four stages in a duration of almost 90-120 minutes makes onesleep cycle. Dreams are common to all stages with the most vividand memorable in the last stage, the common term for which isREM sleep. The sleep cycle is repeated four to five times anight, sometimes going up to seven. This is the reason for manydifferent dreams in one night. Usually the ones in the laststage prior to waking up are the ones recalled. Not being ableto remember the others does not rule out their occurrence. Manyare insistent about not dreaming when the truth is that theysimply don't remember doing so. The Stages Of Sleep On falling asleep, the transition sleep or stage 1 begins,progressing a few minutes later to stage 2 of baseline sleep.This is the stage leading to the other three and accounts fornearly 50-65% of sleep time. Another 15-20 minutes later, itreaches stage 3, followed by stage 4, referred to as delta sleepor slow wave sleep due to the very high voltage slow brainwaves. Delta sleep has a lot in common to a coma, apart frombeing reversible. During the first four stages, a reductiontakes place in respiration and heart rate with the bodyrelatively immobile. After 30 minutes or so of slow wave sleep,there is a sudden lightening into stage 2, rapidly followed
by avery active brain wave pattern called paradoxical or REM sleep.At the same time, respiration and heart rate accelerate withloss of postural and skeletal muscle control. Brain activationoccurs simultaneously causing hallucinations and dreams. NREM In stages 1,2 and 3, it is NREM or non-rapid eye movement sleep,when dreams are not as vivid and eyes move. This inactive stageof sleep makes up 97% of sleep, with only 6% who awaken in NREMbeing able to recollect their dreams. NREM accounts for 78% ofsleep. REM During REM or rapid eye movement, eyes move to and fro underclosed eyelids. REM occurs in stage 4, for as long as one hour,repeating at 90 to 100 minute intervals, three or four times anight. REM increases brain temperature and makes breathing andheartbeat irregular. Blood flow is increased as well. Mostawakening in REM recall dreams vividly due to the brain beingvery active. REM sleep is considered important for memory and learning. Thehypothesis for sleep in general and REM in particular, is ofrestorative nature. Loss of REM sleep causes irritability,anxiety and depression. Many lapse into REM rebound when REMsleep is insufficient. Therefore REM sleep periods are morefrequent in occurrence with a longer than average duration. Interesting Related Forum Discussions: Tips on Staying Awake Dreams Before Birth Controlling Dreams About the author:Dr.Richard Waller has been helping thousands of infetile couplesand gave hope to childless women since 1999 through the processof In-vitrofertilization. He is based in England. please visit http://www.biology-online.org
|
