Wearing shades indoors? Put that issue to bed for a good snooze
A study finds that wearing sunglasses to bed can protect the eyes from blue light and cure tiredness
Teenagers should wear sunglasses to bed to block out sleep-disturbing blue light from phones, computers and tablets, a study suggests.
Blue light from screens can delay the release of sleep-inducing melatonin that interferes with the natural body clock.
Previous research has shown that adolescents who use a computer in the hour before bedtime are three times more likely to get less than five hours’ sleep, which can be hugely disruptive to mood and schoolwork.
As well as symptoms of tiredness and poor concentration, lack of sleep can also increase the risk of more serious long-term health problems such as obesity, diabetes and heart disease.
A study by researchers in the Netherlands found that wearing glasses that filter out the blue light has virtually the same effect on sleep as turning off devices entirely.
Teenagers who used screens before bed needed an extra 30 minutes to get to sleep compared with those who did not, yet the blue light filters helped offset the problem within just a week.
Dr Dirk Jan Stenvers, from Amsterdam University Medical Centre, said: “Adolescents increasingly spend more time on devices with screens, and sleep complaints are frequent in this age group.
“Here we show very simply that these sleep complaints can be easily reversed by minimising evening screen use or exposure to blue light.
“Based on our data, it is likely that adolescent sleep complaints and delayed sleep onset are at least partly mediated by blue light from screens.”
Researchers tested the effects of blocking blue light on 25 frequent users.
Both blocking blue light with glasses and screen abstinence resulted in the onset of sleep and wake-up times that were 20 minutes earlier, and a reduction in reported symptoms of sleep loss in participants, after just one week.
Similarly, the study also showed that filtering out the blue light reduced symptoms of fatigue, lack of concentration and bad mood after just one week.
Glasses and screens that filter blue light are readily available online and at some opticians, but this is the first scientific trial showing they can actually benefit sleep patterns for teenagers.
Stenvers and his colleagues are now investigating whether the relationship between reduced screen time and improved sleep has longer-lasting effects, and whether the same benefits can be detected in adults.
Filters could also help counteract other problems caused by too much blue light.
A 2018 study by Toledo University in Ohio found that blue light from digital devices triggers the production of a toxic chemical that kills light-sensitive cells in our eyes.
The resulting damage can speed up macular degeneration, a condition that affects the middle part of vision. About one in seven people over the age of 50 have some signs of the disease and there is no known cure.
Stenvers added: “Sleep disturbances start with minor symptoms of tiredness and poor concentration, but in the long term we know that sleep loss is associated with increased risk of obesity, diabetes and heart disease.
“If we can introduce simple measures now to tackle this issue, we can avoid greater health problems in years to come.”
The research was presented to the annual meeting of the European Society of Endocrinology in Lyon.
– © Telegraph Media Group Limited (2019)