When we talk about the pitfalls of smartphone addiction, we often refer to visual fatigue, sedentary lifestyles, and lack of human interaction as some of the main negative outcomes. However, it’s quite possible that heavy dependence on smartphones, chats and e-reading sessions – which often keep you plugged in right up to your bedtime – is eating into your sleep!
18-year-old Asmita Mittal always used to have a smartphone or other digital device in front of her when she woke up. This is a common behavioural pattern for teenagers and even adults today, who are glued to their devices almost all the time. But for Asmita, it had actually turned into addiction. She first displayed symptoms of acute attention deficit disorder, and later began experiencing sleeplessness. This is when her parents checked with a doctor, who advised them to establish a no-phone-to-bed rule for the family.
Constant exposure to the screens of digital devices doesn’t just cause digital fatigue to the eyes, but also exposes them to Blue Light.
What is Blue Light?
Visible light has components of several colours corresponding to different wavelengths. Most of us memorised the different colour components of light at school by learning the acronym VIBGYOR. Blue light is the ‘B’in VIBGYOR, or the band of visible light that is blue and corresponds to a wavelength of between 380 nm and 500 nm. This is one of the shortest, highest-frequency and highest-energy wavelengths.
How does blue light affect sleep?
Our natural biological clock, also known as the circadian rhythm, is responsible for keeping our sleep patterns in place. It is our brain which decides when we sleep and when we wake up. When the body is exposed to natural sunlight (and to the darkness after sundown), the brain (specifically the brain’s hypothalamus) sets our body clock. It isnaturally tuned into sleep mode when it is dark and tuned out of sleep mode when there is light. The day and night hormones in the body are triggered by this circadian rhythm. However, when the human body is exposed to too much artificial light at night, the body’s biological clock gets confused, and this natural sleep pattern gets disrupted. This explains why the practice of shutting the light off before bed does more than just serve the aesthetic purpose; it induces the brain towards sleep.
More specifically, it is blue light radiation that interferes with the natural biological clock of the body. So the blue wavelength, which boosts attention span, alacrity and mood during the day to keep us alertand active, becomes disruptive at night as it inhibits the body’s natural rhythm and sleep hormones. Blue light hinders the production of the melatonin hormone that is produced by the body when the brain signals that it’stime to sleep. It is understood that since blue light is a high energy band of light, its shorter wavelengths cause the body to produce less melatonin.
In fact, a study has also highlighted that people who spend too much time reading from light-emitting devices had reduced duration of sleep and less REM sleep (the deep phase of sleep when we dream), as compared to those who read printed books. Research suggests that the disruption of this circadian rhythm can have serious consequences on the body’s health and increase our risk of cardiovascular disease and diabetes, among others. Not to mention about the unappealing phenomenon of being wide awake at night and lethargic as a consequence in the morning.
What can be done to avoid this?
While it is not practically possible to eliminate all blue light from our daily lives, efforts can (and should) be made to limit our body’s exposure to it as much as possible,allowing your body to produce melatonin and get adequate amount and good quality sleep. A few specific tips:
• Make it a rule to remove and stop using all digital devices at least 30 minutes before bedtime, to reduce blue light exposure. This means no smartphone, no television, no tablets, and no e-readers on the bed.
• Turn off LED and CFL light sources an hour before bedtime; use old-school sources of lighting before bed.
• You can also tryusing light shades to dim some of these lights.
• Wearing blue light-filtering glasses can also help
- By Dr. K. Bhujang Shetty, Chairman & Managing Director, Narayana Nethralaya