The Science of Sleep Reading Answers

The Science of Sleep Reading Answers consists of 16 questions and forms part of the evaluation framework for the IELTS General Reading test. Participants are given a time constraint of 20 minutes to finish the reading answers for The Science of Sleep. This portion of the IELTS reading evaluation includes various types of questions, including Do the following statements agree with the information given, writing the correct letter, and writing no more than three words.

The Science of Sleep Reading Answers provides a thorough examination of sleep, which is essential for restoring brain function, emotional balance, and physical health, even though its exact purpose remains unclear. Lack of sleep impairs judgment, coordination, and health, while normal sleep cycles include both non-REM and REM stages that are vital for rest and recovery. For further practice with similar reading evaluations, candidates can check the IELTS Reading Practice Test section.

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The Science of Sleep Reading Answers

We spend a third of our lives doing it. Napoleon, Florence Nightingale and Margaret Thatcher got by on four hours a night. Thomas Edison claimed it was a waste of time. So why do we sleep? This is a question that has baffled scientists for centuries and the answer is, no one is really sure. 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 nightly is miniscule - about the same amount of energy in a piece of toast.

With continued lack of sufficient sleep, the part of the brain that controls language, memory, planning and sense of time is severely affected, practically shut down. 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). This is the legal drink limit in the UK.

Research also shows that sleep-deprived individuals often have difficulty in responding to rapidly changing situations and making rational judgments. In real life situations, the consequences are grave and lack of sleep is said to have been a contributory factor in a number of international disasters such as Exxon Valdez, Chernobyl, Three Mile Island and the Challenger shuttle explosion.

Sleep deprivation not only has a major impact on cognitive functioning but also on emotional and physical health. Disorders such as sleep apnoea, which result in excessive daytime sleepiness have been linked to stress and high blood pressure. 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.

What happens when we sleep?

What happens every time we get a bit of shut eye? 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.

Non-REM sleep: Stage one: Light Sleep

During the first stage of sleep, we’re half awake and half asleep. Our muscle activity slows down and slight twitching may occur. This is a period of light sleep, meaning we can be awakened easily at this stage.

Stage two: True Sleep

Within ten minutes of light sleep, we enter stage two, which lasts around 20 minutes. The breathing pattern and heart rate start to slow down. This period accounts for the largest part of human sleep.

Stages three and four: Deep Sleep

During stage three, the brain begins to produce delta waves, a type of wave that is large (high amplitude) and slow (low frequency). Breathing and heart rate are at their lowest levels.

Stage four is characterised by rhythmic breathing and limited muscle activity. If we are awakened during deep sleep we do not adjust immediately and often feel groggy, or sleepy for several minutes after waking up. Some children experience bed-wetting, night terrors or sleepwalking during this stage.

REM sleep: The first rapid eye movement (REM) sleep occurs about 70 to 90 minutes after we fall asleep. We have around three to five REM episodes each night. During REM sleep, the brain is very active - often more so than when we are awake. This is the period when most dreams occur. The eyes dart around (hence the name), our breathing rate rises and our blood pressure increases, but the body is effectively paralysed, said to be nature’s way of preventing us from acting out our dreams. After REM sleep, the whole cycle begins again. How much sleep is required? There is no set amount of time that people need to sleep, since it varies from person to person.

Average sleep times per day

Species: Average total sleep time per day

Python: 18 hrs, Tiger: 15.8 hrs, Cat: 12.1 hrs, Sheep: 3.8 hrs, African elephant: 3.3 hrs, Giraffe: 1.9 hrs

The current world record for the longest period without sleep is 11 days, set by Randy Gardner in 1965. Four days into the experiment, he began hallucinating. This was followed by a delusion where he thought he was a famous footballer. Surprisingly, Randy was still physically functioning quite well at the end of his research and he could still beat the scientist at pinball.

QUESTIONS 15-22

DO THE FOLLOWING STATEMENTS AGREE WITH THE INFORMATION GIVEN IN READING PASSAGE 1?

IN BOXES 15-22 ON YOUR ANSWER SHEET, WRITE

TRUE if the statement agrees with the information

FALSE if the statement contradicts the information

NOT GIVEN if there is no information on this

15. Thomas Edison slept 4 hours a night.

Supporting statement: “Thomas Edison claimed it was a waste of time.”

Keywords: Thomas Edison, waste of time, sleep

Keyword Location: Paragraph 1, line 3

Explanation: The passage only states Edison thought sleep was a waste of time; it does not mention that he slept 4 hours a night like others listed. Hence, the statement is false.

16. Scientists don't have a certain answer for why we have to sleep.

Supporting statement: “This is a question that has baffled scientists for centuries and the answer is, no one is really sure.”

Keywords: scientists, baffled, no one sure, why we sleep

Keyword Location: Paragraph 1, lines 4–5

Explanation: The text clearly confirms that scientists are uncertain about the real reason for sleep, so the statement is true.

17. Lack of sleep might cause various problems.

Supporting statement: “Sleep deprivation not only has a major impact on cognitive functioning but also on emotional and physical health.”

Keywords: sleep deprivation, major impact, cognitive, emotional, physical health

Keyword Location: Paragraph 4, line 1

Explanation: The text highlights several negative effects of lack of sleep, confirming that it causes various problems.

18. Sleep-deprivation may be the cause of anorexia.

Supporting statement: “Research has also suggested that sleep loss may increase the risk of obesity…”

Keywords: sleep loss, increase, risk, obesity

Keyword Location: Paragraph 4, line 4

Explanation: The passage connects sleep deprivation to obesity, not anorexia, making this statement false.

19. There are four stages of the REM sleep.

Supporting statement: “Sleep occurs in a recurring cycle... divided into two categories: non-REM (which is further split into four stages) and REM sleep.”

Keywords: REM, non-REM, four stages

Keyword Location: Paragraph 5, lines 2–3

Explanation: There are four stages of non-REM sleep, not REM sleep. Thus, the statement is false.

20. According to Jim Horne, we need to sleep as much as it takes to not be sleepy during the day.

Supporting statement: No mention of Jim Horne or his view on sleep duration.

Keywords: Jim Horne, amount of sleep, not sleepy during day

Keyword Location: —

Explanation: The passage provides no reference to Jim Horne or his opinion, so the statement is not given.

21. Giraffes require less sleep than dogs.

Supporting statement: “Giraffe: 1.9 hrs” and “Tiger: 15.8 hrs… Cat: 12.1 hrs…”

Keywords: giraffe, less sleep, animals

Keyword Location: Sleep table, last lines

Explanation: Giraffes sleep only 1.9 hours per day, less than most animals, including dogs (not listed but known to sleep more). Hence, true.

22. After four sleepless days, Randy had a delusion about him being a football celebrity.

Supporting statement: “Four days into the experiment, he began hallucinating. This was followed by a delusion where he thought he was a famous footballer.”

Keywords: four days, delusion, footballer

Keyword Location: Last paragraph, lines 2–3

Explanation: The text confirms Randy Gardner experienced a delusion of being a footballer after four sleepless days, making this true.

QUESTIONS 23-24

CHOOSE THE CORRECT LETTER, A, B, C OR D.

23. During the Light Sleep stage:

A. Muscle activity increases

B. Jiggling might occur

C. It is not easy to be woken up

D. After waking up, one may experience slight disorientation

Supporting statement: “Our muscle activity slows down and slight twitching may occur.”

Keywords: muscle activity, slows down, twitching

Keyword Location: Stage one (Light Sleep), lines 2–3

Explanation: The phrase “slight twitching” corresponds to jiggling, indicating this is the correct choice.

24. Heart rate is at the lowest level during:

A. Light Sleep stage

B. Rem Sleep

C. True Sleep stage

D. Third Sleep stage

Supporting statement: “During stage three, the brain begins to produce delta waves… Breathing and heart rate are at their lowest levels.”

Keywords: stage three, delta waves, lowest heart rate

Keyword Location: Stage three, lines 1–3

Explanation: The passage specifies that heart rate and breathing reach their lowest levels during Stage three, confirming option D.

QUESTIONS 25-27

CHOOSE THE CORRECT LETTER, A, B, C OR D.

25. The brain activity is really high:

A. During REM sleep

B. During the stage of True Sleep

C. When we are awake

D. During the Deep sleep stage

Supporting statement: “During REM sleep, the brain is very active — often more so than when we are awake.”

Keywords: REM sleep, brain very active

Keyword Location: REM sleep paragraph, line 2

Explanation: The brain’s highest activity occurs during REM sleep, as explicitly mentioned, so A is correct.

26. Humans require at least:

A. 7.75 hours of sleep

B. 5 hours of sleep

C. 8 hours

D. There is no set amount of time

Supporting statement: “There is no set amount of time that people need to sleep, since it varies from person to person.”

Keywords: no set amount, varies

Keyword Location: Paragraph before the sleep table

Explanation: The passage directly says sleep duration varies among individuals, confirming D.

27. Pythons need:

A. Less sleep than tigers

B. Twice as much sleep as cats

C. Almost ten times more sleep than giraffes

D. More sleep than any other animal in the world

Supporting statement: “Python: 18 hrs… Giraffe: 1.9 hrs”

Keywords: Python, Giraffe, 18 hrs, 1.9 hrs

Keyword Location: Sleep table

Explanation: The python sleeps around 18 hours, which is nearly ten times more than the giraffe’s 1.9 hours, confirming C.

QUESTIONS 28-30

WRITE NO MORE THAN THREE WORDS FROM THE PASSAGE FOR EACH ANSWER.

WRITE YOUR ANSWERS IN BOXES 28-30 ON YOUR ANSWER SHEET.

28. If we continually lack sleep, the specific part of our brain that controls language is …………

Supporting statement: “With continued lack of sufficient sleep, the part of the brain that controls language, memory, planning and sense of time is severely affected.”

Keywords: brain, language, severely affected

Keyword Location: Paragraph 2, line 1

Explanation: The text clearly states that the language-controlling part of the brain is severely affected due to continued lack of sleep.

29. True Sleep lasts approximately …………………

Supporting statement: “Within ten minutes of light sleep, we enter stage two, which lasts around 20 minutes.”

Keywords: stage two, lasts, 20 minutes

Keyword Location: Stage two (True Sleep), line 2

Explanation: The “True Sleep” stage lasts around 20 minutes, which is the direct answer from the passage.

30. Although during REM sleep our breathing rate and blood pressure rise, our bodies………….

Supporting statement: “Our breathing rate rises and our blood pressure increases, but the body is effectively paralysed.”

Keywords: breathing rate, blood pressure, paralysed

Keyword Location: REM sleep paragraph, lines 3–4

Explanation: During REM sleep, the body remains effectively paralysed despite heightened brain activity, preventing dream enactment.

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