front 1 Circadian rhythm | back 1 the 24-hour internal clock in our brain that regulates cycles of alertness and sleepiness by responding to light changes in our environment. |
front 2 Dreams | back 2 a series of thoughts, images, and sensations occurring in a person's mind during sleep. |
front 3 Electroencephalograph (EEG) | back 3 a recording of brain activity |
front 4 Hypersomnia | back 4 the inability to stay awake and alert during the day despite having more than an adequate amount of nighttime sleep. |
front 5 Insomnia | back 5 habitual sleeplessness; inability to sleep. |
front 6 Melatonin | back 6 a hormone secreted by the pineal gland which inhibits melanin formation and is thought to be concerned with regulating the reproductive cycle. |
front 7 Napping | back 7 sleep lightly or briefly, especially during the day. |
front 8 Narcolepsy | back 8 Excessive daytime sleepiness. People with narcolepsy fall asleep without warning. It can happen anywhere and at any time |
front 9 Night Terrors | back 9 feelings of great fear experienced on suddenly waking in the night. |
front 10 Nightmares | back 10 a frightening or unpleasant dream. |
front 11 Parasomnia | back 11 An abnormal disruption of sleep, such as sleep walking, sleep talking, nightmares, bedwetting, sleep apnea (problems with breathing that cause loud snoring), or nighttime seizures |
front 12 Restless Legs Syndrome | back 12 a disorder characterized by the occurrence of uncomfortable sensations in the legs and the urge to move them in order to relieve the sensations, typically occurring in the evening or at night and often interfering with sleep. |
front 13 Sleep | back 13 a condition of body and mind that typically recurs for several hours every night, in which the eyes are closed, the postural muscles relaxed, the activity of the brain altered, and consciousness of the surroundings practically suspended. |
front 14 Sleep apnea | back 14 a potentially serious sleep disorder in which breathing repeatedly stops and starts |
front 15 Sleep deprivation | back 15 the situation or condition of suffering from a lack of sleep. |
front 16 Sleep paralysis | back 16 a feeling of being conscious but unable to move |
front 17 Sleep study | back 17 a test used to diagnose sleep disorders |
front 18 Snoring | back 18 the action or fact of making a snorting or grunting sound while asleep. |
front 19 Stage 1 (Non-REM) sleep | back 19 the first sleep stage you enter when nodding off |
front 20 Stage 2 (Non-REM) sleep | back 20 a continued slowing of heartbeat, breathing, muscle activity, and eye movements. |
front 21 Stage 3 (Non-REM) sleep | back 21 a period of deep sleep where any environmental noises or activity may fail to wake the sleeping person |
front 22 Stage 4 (REM Sleep) | back 22 the stage of sleep where most dreams happen |
front 23 Somnambulism | back 23 sleepwalking. |
front 24 Wakefulness | back 24 not sleeping or able to sleep : sleepless. |