Long latencies are helpful in distinguishing physical tiredness or fatigue from true sleepiness. Or measures how sleepy you are by observing how long it takes you to fall asleep. Or apnea caused by blockage of the airway. 2, cessation of breathing during sleep, due to a mechanical obstruction, such as a semi-collapsed trachea, tongue relaxed to back of the throat, or a large amoung of tissue in the uvula area. Chemical symbol for oxygen.
People normally sleep in patterns that follow four definite, gradual stages.
The REM sleep periods, lasting from a few minutes to half an hour, alternate with the NREM periods. Dreaming occurs during REM time. Individual sleep patterns change throughout life because daily need for sleep gradually diminish from s much as 20 hours a day in infancy to as little as 6 hours a day in old age. Infants tend to begin a sleep period with REM sleep, whereas REM activity usually follows the four stages of NREM sleep in adults. Somnambulism, sleep terror, and sleep-related enuresis episodes generally start in stage 4 or during arousals from this stage.