Beware of Blue Light if you want to get Better Sleep

Beware of Blue Light if you want to get Better Sleep

What is blue light?

Why should one beware of blue light? To explain this one should first understand what is meant by blue light. Blue light is a bandwidth in the visible light spectrum, defined as having a wavelength of between 400−495 nm.

This high-energy, visible blue light is normally transmitted through the eye to the retina.

Sources of blue light

Digital and elctronic devices, such as cell phones, tablets, TV screens and computer monitors emit significant levels of blue light.

Compact fluorescent light bulbs, high-intensity headlights and other LED lighting also emit higher blue light energy than the traditional incandescent light bulbs.

What are the effects of exposure to blue light?

Living in the Fourth Industrial Revolution, a time where digital technology is pervasive in our schools, homes and offices, we are being exposed to more blue light than ever before.

An article published in The Lancet Psychiatry found that those with disrupted sleep patterns were more likely to have depression or bipolar disorder, but the worst of those affected were described by one of the authors, Prof. Daniel Smith at the University of Glasgow, as having “very poor sleep hygiene – people on their mobile phones at midnight checking Facebook or getting up to make a cup of tea in the middle of the night”. 

Dr. Michael Breus, The Sleep Doctor, says scientific studies have pinpointed blue light as a form of light that’s especially aggressive in triggering sleeplessness. Blue light suppresses melatonin production for more than twice as long as other light wavelengths, and alters circadian rhythms by twice the degree.

New Research

New research in Science Daily discusses the power of blue light to interfere with sleep and why you should beware of blue light. Researchers found blue light prevented body temperature from dropping during the night, a vital element of the body’s progression into sleep.

The study also compared the effects of blue light and red light (a bandwidth of light with a longer wavelength).  Scientists found red light exposure during the same 2-hour evening time period did not interfere with sleep and circadian biology.  

The Cons of Blue Light Exposure 2 hours before sleep time:

Disrupts the body’s 24-hour circadian rhythm, which can have a significant effect on health:

  • Lowered immunity
  • Increased risk of depression and bi-polar disorder
  • Increased risk of breast and prostate cancer
  • Increased risk of cardiovascular problems
  • Increased risk of dementia

The Pros of Blue Light Exposure:

While a hazard to health and sleep at night, blue light exposure can be helpful during the day, especially in the morning and early afternoon. Research shows exposure to blue-light during daytime hours can be beneficial in several ways, including:

  • Reduces daytime sleepiness and elevates alertness
  • Increases reaction times
  • Increases memory and cognitive function
  • Elevates mood
  • Improves concentration span

Glasses to help you sleep

Dr. Robert Daniel, Specialist Ophthalmologist, Johannesburg, recently told Carte Blanche, “An adult needs between 7 to 8 hours of sleep per night and somehow we’ve come to think that the less you sleep the more lazy you are and we almost pride ourselves in saying that we can manage on 4 hours a night, but that’s actually very dangerous. “

Around 2005 a new retinal receptor, which responds only to the colour blue, (the same as sky blue) was discovered.  Dr. Daniel’s interest in the switch between day and night, which is fundamental for sleep, was piqued and he invented SleepSpec, glasses that cut out the specific bandwidth of blue light between 460–480nm in the light spectrum.

“I realise that having no screen time is not practical today, the trouble is that most of our lighting also contains the blue, so I designed a lens that cuts out the blue light in front of your eye with a pair of glasses”, says Dr. Daniel.

According to The Sleep Doctor, night-time blue light exposure is harmful to sleep and circadian rhythms so taking steps to manage blue light exposure, including using red light sources during evening hours, can make a real difference.

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