The science of sleep

annette H. (Switzerland)
65 words 70 learners

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words only definitions & notes
  1. grogginess
    a state of being half-awake
    If you've ever pulled an all-nighter, you'll be familiar with the following after-effects: grumpiness, grogginess, irritability and forgetfulness.
  2. hallucinate
    have illusions; perceive what is not actually there
    Four days into the research, he began hallucinating.
  3. disorient
    cause to be lost or confused
    If we are awakened during deep sleep we do not adjust immediately and often feel groggy and disoriented for several minutes after waking up.
  4. sleepwalk
    walk in one's sleep
    Some children experience bed-wetting, night terrors, or sleepwalking during this stage.
  5. low frequency
    30 to 300 kilohertz
    During stage three, the brain begins to produce delta waves, a type of wave that is large (high amplitude) and slow (low frequency).
  6. bed-wetting
    enuresis during sleep; especially common in children
    Some children experience bed-wetting, night terrors, or sleepwalking during this stage.
  7. grumpiness
    a fussy and eccentric disposition
    If you've ever pulled an all-nighter, you'll be familiar with the following after-effects: grumpiness, grogginess, irritability and forgetfulness.
  8. miniscule
    very small
    Some believe that sleep gives the body a chance to recuperate from the day's activities but in reality, the amount of energy saved by sleeping for even eight hours is miniscule - about 50 kCal, the same amount of energy in a piece of toast.
  9. sleep deprivation
    a form of psychological torture inflicted by depriving the victim of sleep
    Sleep deprivation not only has a major impact on cognitive functioning but also on emotional and physical health.
  10. attention span
    the length of time you can concentrate on some idea or activity
    After just one night without sleep, concentration becomes more difficult and attention span shortens considerably.
  11. disoriented
    having lost your bearings
    If we are awakened during deep sleep we do not adjust immediately and often feel groggy and disoriented for several minutes after waking up.
  12. act out
    represent an incident, state, or emotion by action, especially on stage
    However, our bodies are effectively paralysed, said to be nature's way of preventing us from acting out our dreams.
  13. cognitive
    relating to or involving the mental process of knowing
    We have to sleep because it is essential to maintaining normal levels of cognitive skills such as speech, memory, innovative and flexible thinking.
  14. amplitude
    greatness of magnitude
    During stage three, the brain begins to produce delta waves, a type of wave that is large (high amplitude) and slow (low frequency).
  15. get by
    pass or move in front of
    Napoleon, Florence Nightingale and Margaret Thatcher got by on four hours a night.
  16. twitch
    make an uncontrolled, short, jerky motion
    Our muscle activity slows down and slight twitching may occur.
  17. irritability
    an irritable petulant feeling
    If you've ever pulled an all-nighter, you'll be familiar with the following after-effects: grumpiness, grogginess, irritability and forgetfulness.
  18. recur
    happen or occur again
    Sleep occurs in a recurring cycle of 90 to 110 minutes and is divided into two categories: non-REM (which is further split into four stages) and REM sleep.
  19. challenger
    the contestant you hope to defeat
    In real life situations, the consequences are grave and lack of sleep is said to have been be a contributory factor to a number of international disasters such as Exxon Valdez, Chernobyl, Three Mile Island and the Challenger shuttle explosion.
  20. obesity
    the condition of being excessively overweight
    Research has also suggested that sleep loss may increase the risk of obesity because chemicals and hormones that play a key role in controlling appetite and weight gain are released during sleep.
  21. judgement
    the act of judging or assessing a person or situation
    Research also shows that sleep-deprived individuals often have difficulty in responding to rapidly changing situations and making rational judgements.
  22. forgetfulness
    tendency to forget
    If you've ever pulled an all-nighter, you'll be familiar with the following after-effects: grumpiness, grogginess, irritability and forgetfulness.
  23. research
    a seeking for knowledge
    Research also shows that sleep-deprived individuals often have difficulty in responding to rapidly changing situations and making rational judgements.
  24. frequency
    the number of occurrences within a given time period
    During stage three, the brain begins to produce delta waves, a type of wave that is large (high amplitude) and slow (low frequency).
  25. adjust
    alter or regulate so as to conform to a standard
    If we are awakened during deep sleep we do not adjust immediately and often feel groggy and disoriented for several minutes after waking up.
  26. decrease
    a change downward
    In fact, 17 hours of sustained wakefulness leads to a decrease in performance equivalent to a blood alcohol level of 0.05% (two glasses of wine).
  27. flexible
    able to bend easily
    We have to sleep because it is essential to maintaining normal levels of cognitive skills such as speech, memory, innovative and flexible thinking.
  28. occur
    come to pass
    Sleep occurs in a recurring cycle of 90 to 110 minutes and is divided into two categories: non-REM (which is further split into four stages) and REM sleep.
  29. dart
    a sudden quick movement
    Our eyes dart around (hence the name), our breathing rate and blood pressure rise.
  30. delusion
    a mistaken or unfounded opinion or idea
    This was followed by a delusion where he thought he was a famous footballer.
  31. deprive
    take away
    Research also shows that sleep-deprived individuals often have difficulty in responding to rapidly changing situations and making rational judgements.
  32. amount
    how much there is of something that you can quantify
    Some believe that sleep gives the body a chance to recuperate from the day's activities but in reality, the amount of energy saved by sleeping for even eight hours is miniscule - about 50 kCal, the same amount of energy in a piece of toast.
  33. lack
    the state of needing something that is absent or unavailable
    Lack of sleep has serious effects on our brain's ability to function.
  34. effectively
    in a manner producing an intended result
    However, our bodies are effectively paralysed, said to be nature's way of preventing us from acting out our dreams.
  35. sustain
    lengthen or extend in duration or space
    In fact, 17 hours of sustained wakefulness leads to a decrease in performance equivalent to a blood alcohol level of 0.05% (two glasses of wine).
  36. respond
    show a reaction to something
    Research also shows that sleep-deprived individuals often have difficulty in responding to rapidly changing situations and making rational judgements.
  37. period
    an amount of time
    This is a period of light sleep, meaning we can be awakened easily at this stage.
  38. in other words
    otherwise stated
    In other words, sleep plays a significant role in brain development.
  39. disorder
    a condition in which things are not in their expected places
    Disorders such as sleep apnoea which result in excessive daytime sleepiness have been linked to stress and high blood pressure.
  40. require
    have need of
    Jim Horne from Loughborough University's Sleep Research Centre has a simple answer though: "The amount of sleep we require is what we need not to be sleepy in the daytime."
  41. account for
    be the reason or explanation for
    This period accounts for the largest part of human sleep.
  42. impact
    the striking of one body against another
    Sleep deprivation not only has a major impact on cognitive functioning but also on emotional and physical health.
  43. equivalent
    being essentially comparable to something
    In fact, 17 hours of sustained wakefulness leads to a decrease in performance equivalent to a blood alcohol level of 0.05% (two glasses of wine).
  44. appetite
    a feeling of craving something
    Research has also suggested that sleep loss may increase the risk of obesity because chemicals and hormones that play a key role in controlling appetite and weight gain are released during sleep.
  45. indicate
    designate a place, direction, person, or thing
    Results from the sleep profiler indicate that people like to sleep anywhere between 5 and 11 hours, with the average being 7.75 hours.
  46. affect
    have an influence upon
    With continued lack of sufficient sleep, the part of the brain that controls language, memory, planning and sense of time is severely affected, practically shutting down.
  47. average
    an intermediate scale value regarded as normal or usual
    Results from the sleep profiler indicate that people like to sleep anywhere between 5 and 11 hours, with the average being 7.75 hours.
  48. varied
    characterized by diversity
    Even animals require varied amounts of sleep:
    Species Average total sleep time per day
    Python 18 hrs
    Tiger 15.8 hrs
    Cat 12.1 hrs
    Chimpanzee 9.7 hrs
    Sheep 3.8 hrs
    African elephant 3.3 hrs
    Giraffe 1.9 hr
    The current world record for the longest period without sleep is 11 days, set by Randy Gardner in 1965.
  49. essential
    basic and fundamental
    We have to sleep because it is essential to maintaining normal levels of cognitive skills such as speech, memory, innovative and flexible thinking.
  50. waste
    use inefficiently or inappropriately
    Thomas Edison claimed it was waste of time.
  51. ability
    the quality of having the means or skills to do something
    Lack of sleep has serious effects on our brain's ability to function.
  52. limited
    subject to restrictions or constraints
    Stage four is characterised by rhythmic breathing and limited muscle activity.
  53. result
    something that follows as a consequence
    Disorders such as sleep apnoea which result in excessive daytime sleepiness have been linked to stress and high blood pressure.
  54. consequence
    a phenomenon that is caused by some previous phenomenon
    In real life situations, the consequences are grave and lack of sleep is said to have been be a contributory factor to a number of international disasters such as Exxon Valdez, Chernobyl, Three Mile Island and the Challenger shuttle explosion.
  55. effect
    a phenomenon that is caused by some previous phenomenon
    Lack of sleep has serious effects on our brain's ability to function.
  56. slight
    small in quantity or degree
    Our muscle activity slows down and slight twitching may occur.
  57. hence
    from that fact or reason or as a result
    Our eyes dart around (hence the name), our breathing rate and blood pressure rise.
  58. species
    taxonomic group whose members can interbreed
    Even animals require varied amounts of sleep:
    Species Average total sleep time per day
    Python 18 hrs
    Tiger 15.8 hrs
    Cat 12.1 hrs
    Chimpanzee 9.7 hrs
    Sheep 3.8 hrs
    African elephant 3.3 hrs
    Giraffe 1.9 hr
    The current world record for the longest period without sleep is 11 days, set by Randy Gardner in 1965.
  59. increase
    a process of becoming larger or longer or more numerous
    Research has also suggested that sleep loss may increase the risk of obesity because chemicals and hormones that play a key role in controlling appetite and weight gain are released during sleep.
  60. sufficient
    of a quantity that can fulfill a need or requirement
    With continued lack of sufficient sleep, the part of the brain that controls language, memory, planning and sense of time is severely affected, practically shutting down.
  61. difficulty
    an effort that is inconvenient
    Research also shows that sleep-deprived individuals often have difficulty in responding to rapidly changing situations and making rational judgements.
  62. loss
    the act of losing someone or something
    Research has also suggested that sleep loss may increase the risk of obesity because chemicals and hormones that play a key role in controlling appetite and weight gain are released during sleep.
  63. island
    a land mass that is surrounded by water
    In real life situations, the consequences are grave and lack of sleep is said to have been be a contributory factor to a number of international disasters such as Exxon Valdez, Chernobyl, Three Mile Island and the Challenger shuttle explosion.
  64. account
    a record or narrative description of past events
    This period accounts for the largest part of human sleep.
  65. further
    to or at a greater extent or degree or a more advanced stage
    Sleep occurs in a recurring cycle of 90 to 110 minutes and is divided into two categories: non-REM (which is further split into four stages) and REM sleep.
Created on Thu Nov 03 17:40:45 EDT 2011

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