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LanguageCert Practice Reading: Part 2 (Sentence Matching)
ID: #60283
Hard
Yellow 7
Instructions
You are going to read an extract from Research into Screen use and Sleep.
Blue light and sleep
Some years ago, several studies found that the blue light that mobile phones, computers and TV screens send out can cause people to have difficulties in falling and staying asleep. The common assumption was, therefore, that anyone who was in the habit of spending time online or scrolling through newsfeeds on their phones late at night could find themselves at risk of experiencing insomnia. 1Drop sentence here. But changing their bedtime routines to exclude electronic devices doesn’t always have any impact on those symptoms.
That early research is now being reconsidered, however, with new studies pointing to a more complicated scenario. It’s true that blue or short-wavelength light, which includes daylight as well as screens, affects circadian rhythms. This natural 24-hour internal ‘clock’ in the brain controls how alert or sleepy people are throughout the day. The rhythm is based on changes in light in the surrounding environment, and it’s also connected to the Earth’s rotation around its axis. 2Drop sentence here.
Neuroscientists explain that sleep is a complex process. Receptors in the eyes tell the brain when the individual should be awake and when they should be asleep, in response to cells absorbing blue light. 3Drop sentence here. This suggests that the colour of the light sent out by screens isn’t responsible for interrupting sleep, but rather that it’s the period of exposure and the brightness of the light that might be causing problems.
What’s more, screens are actually fairly dull compared to daylight, which is a thousand times brighter than a smartphone’s glow. Even the lights in the home are ten times brighter. 4Drop sentence here. The conclusion has to be, therefore, that using screens for a few minutes before going to sleep has less impact than was previously thought. That is, unless, the screen is at full brightness for several hours, and the user has existing sleep problems. 5Drop sentence here.
Many phones have in-built blue-light filters, which are said to be kinder on the eyes and brain. These have been shown to provide relief from the eye strain that comes from long-term exposure to harsh light. But it turns out they may not be particularly effective in protecting sleep. One sleep study carried out by Harvard University in the USA found there was relatively minor interference with sleep even after four hours of looking at bright light prior to bedtime. 6Drop sentence here. This finding leads researchers to say that the content of what the user is reading on-screen is more likely to have an effect on their ability to fall asleep than the light itself.
A
Indeed, people often blame such activities when they begin to experience sleeplessness, disturbed nights and resulting tiredness
B
But scientists believe it's better to research the health effects of blue-light exposure
than develop such measures
C
Only in those particular circumstances does screen use appear to become particularly problematic
D
In fact, this resulted in only a ten-minute delay compared with people in a control group who had no such exposure
E
This is what tells people when it's time to get up or time to go to bed
F
But such signals can also come from longer wavelengths of light, which may actually be red
G
This evidence gave blue light a bad name around a decade ago, when scientists first suggested it could be causing problems
H
Despite stimulation from these near-constant light sources, most people still fall
asleep at night
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