Category: Sleep

The ‘melanopic display’ is able to reduce or increase the colour.

Cyan — the greenish-blue colour that smartphones and other devices emit — could stop people sleeping properly.

People exposed to screens which emit less cyan felt more sleepy and had higher levels of the ‘sleep hormone’ melatonin in their system, new research finds.

However, those exposed to more cyan felt more awake and had lower levels of melatonin in their system.

The researchers developed a new type of visual display for their tests.

The ‘melanopic display’ is able to reduce or increase the amount of cyan, while keeping colours true.

Here are some different types of cyan:

Professor Rob Lucas, study co-author, said:

“This outcome is exciting because it tells us that regulating exposure to cyan light can influence how sleepy we feel.

Our study also shows how we can use that knowledge to improve the design of visual displays.

We built our melanopic display by adapting a data projector, but we would expect that this design could be applied to any type of display.

Such displays could, for example, help phone obsessed teenagers to fall asleep, or support alertness in people who need to use a computer at night.”

For the study, people watched a movie either with or without cyan.

Both movies looked the same as the technology balances out the other colours.

Melatonin levels were tested from saliva samples and people were asked how sleepy they felt afterwards.

Dr Annette Allen, the study’s first author, said:

“The new display design could actually have a wider benefit, as it seems that this technology also improves image appearance.

Like adding salt to food, we aren’t necessarily aware that it’s been done though we appreciate the effect.

Exploiting metamerism to regulate the impact of a visual display on alertness and melatonin suppression independent of visual appearance”

The study was published in the journal Sleep (Allen et al., 2018).

People slept better, awakened less in the night and felt better the next day.

Opening the windows or doors before going to bed can improve sleep quality, new research finds.

Both measures help to decrease levels of carbon dioxide and increase air quality.

In fresher air, people sleep better, awaken less in the night and feel better the next day.

The study’s authors summarise their results:

“It has been shown that when bedroom air quality was improved in these experiments:

• Subjects reported that the bedroom air was fresher.
• Sleep quality improved.
• Responses on the Groningen Sleep Quality scale improved.
• Subjects felt better next day, less sleepy, and more able to concentrate.
• Subjects’ performance of a test of logical thinking improved.”

In the studies the fresher air was achieved first by opening the window and secondly by using a special vent.

Of course, opening the window is not always possible because of noise pollution and heat conservation.

When it is possible, though, ventilation can have a dramatic effect on air quality and on sleep, the authors write:

“There is no doubt that both interventions did improve bedroom air quality – the effective outdoor air supply rate was found to be greater by a factor of at least 10 if the window was open and by a factor of at least four if an air supply fan was covertly operated whenever the CO₂ concentration was above 900 ppm.”

The study was published in the journal Indoor Air (Strøm-Tejsen et al., 2015).