THE IMPACT OF BLUE LIGHT
You may have heard already that using handheld and electronic devices close to sleep time can disrupt our sleep.
But what’s the reality here and what does the science tell us.
Let’s have a look at a couple of things; the elements that help us sleep and then what impact our devices could have and why.
First off, to sleep itself.
Sleep is simple, isn’t it? We close our eyes and rest for a while and then we wake up. It’s that simple, right?
Well not quite.
Sleep is actually a complex interaction of systems, hormones and neurotransmitters inside us to promote the optimum environment for us to get proper rest.
Our sleep-wake cycle is an element of what is known as the circadian rhythm; the roughly 24 cycle of a variety of our physiological mechanisms.
You may already have heard of melatonin, which is a key hormone involved in our sleep-wake cycle. Melatonin is often referred to as the sleep hormone, for its release helps prepare the body for sleep; lowering our body temperature and making us feel less alert.
An important aspect of how the body knows to start releasing melatonin is through external light picked up by our eyes. Light enters the eye and hits the retina. As this level of received light decreases, this promotes the body to increase melatonin production. Similarly, as the level of received light increases, this promotes a decrease in melatonin levels.
So light is a key element of our sleep-wake cycle and given that our devices give off light is it just the aspect of light that could have an impact?
Well, yes and no. It’s also the wavelength of the light being given off or we might know it by the colour of that light. In the sunlight wave spectrum, the blue end of the scale has the highest relative energy. When we look at the artificial light sources we use, the LCD lights of display screens shows a spike in the blue end of the light spectrum.
So if light from LCD screens can be quite similar to daylight, then it’s not really a surprise our bodies react accordingly.
Since we’re talking about light waves, another interesting aspect of our sleep cycle to look at is the change in brain wave pattern emitted during sleep and wakefulness.
Our brains produce a variety of different brain waves at different times. A quick overview tells us that:
Beta brain waves are most associated with our waking state.
Alpha brain waves are associated with periods of waking and deep relaxation.
Theta waves occur during the lighter stages of Non-REM sleep;
while Delta brain waves are present in our deepest sleep states.
Research carried out on the impact of exposure to blue light has demonstrated a link between short term blue light exposure and a decrease in alpha, theta and delta brain waves. So again, this may be another avenue through which blue light can impact our sleep-wake cycle.
While studies have supported the impact of blue light for enhancing our alertness and concentration; perhaps, alertness and concentration are not what we’re aiming for when we want restful sleep states.
So this is worth considering when we want to promote optimum sleep environments for ourselves.
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