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).

It almost doubled the amount of times that people awoke during the night.

The blue light emitted by screens damages the length and quality of sleep, new research finds.

Screens that emit redder light, though, do not damage sleep in the same way.

Professor Abraham Haim, one of the study’s authors, said:

 “The light emitted by most screens — computers, smartphones, and tablets — is blue light that damages the body’s cycles and our sleep.

The solution must be the use of the existing filters that prevent the emission of this light.”

Screens are particularly damaging to sleep if used at bedtime.

The screens suppress the secretion of melatonin, the hormone that helps control the body’s sleep-wake cycle.

One of the ways blue light damages sleep, the researchers found, was by interrupting how they body regulates its temperature.

Professor Haim said:

“Naturally, when the body moves into sleep it begins to reduce its temperature, reaching the lowest point at around 4:00 a.m.

When the body returns to its normal temperature, we wake up.

After exposure to red light, the body continued to behave naturally, but exposure to blue light led the body to maintain its normal temperature throughout the night — further evidence of damage to our natural biological clock.”

Blue light compared to red light almost doubled the amount of times that people awoke during the night.

Professor Haim said:

“Exposure to screens during the day in general, and at night in particular, is an integral part of our technologically advanced world and will only become more intense in the future.

However, our study shows that it is not the screens themselves that damage our biological clock, and therefore our sleep, but the short-wave blue light that they emit.

Fortunately various applications are available that filter the problematic blue light on the spectrum and replace it with weak red light, thereby reducing the damage to the suppression of melatonin.”

The study was published in the journal Chronobiology International (Green et al., 2017).

Two surveys hint at links between sleep position, personality and the strength of your relationship.

People who are more creative tend to sleep on their left-hand-side, a survey finds.

The survey also found that people who are more extraverted tend to sleep closer to their partners.

In fact, being in closer contact with your partner during sleep was related to having a better relationship.

12% of couples spend the night less than 1 inch apart.

Among these couples, 86% were happy with their relationship.

On the other hand, 2% slept more than 30 inches apart.

Among these couples the amount happy with their relationship dropped to 66%.

Touching was also an important factor, said Professor Richard Wiseman, who conducted the survey:

“One of the most important differences involved touching, with 94% of couples who spent the night in contact with one another were happy with their relationship, compared to just 68% of those that didn’t touch.”

It did not seem to make much difference in which direction couples were sleeping.

The most popular sleeping positions for couples were:

• 42% slept back to back,
• 31% slept facing the same direction,
• and 4% slept facing each other.

A previous survey for a budget hotel chain also examined the link between sleep position and personality.

It found that:

• 41% slept in the foetal position. This was linked to having a sensitive heart and being a little shy.
• 15% adopted the ‘log’, lying on your side with arms by your side. These people were easy-going and social.
• 13% slept in the ‘yearning’ position: same as the log but with arms outstretched. Yearners have open natures, but can be cynical.
• 8% slept like soldiers, on their backs with arms by their sides. These are quiet and reserved people who don’t like to make a fuss, the survey suggested.
• 7% slept in free fall, face down, hands around the pillow. These were somewhat thin-skinned people, often extroverted and brash.

Speaking about his survey, Professor Wiseman said:

“This is the first survey to examine couples’ sleeping positions, and the results allow people to gain an insight into someone’s personality and relationship by simply asking them about their favourite sleeping position.”

The surveys were conducted to publicise a book and a budget hotel chain, respectively. In other words: take with a pinch of salt.