Ok, so here’s the 411. The light we’re surrounded by during the day is made up of a whole load of electromagnetic particles. Sorry, what? Basically, they’re the smallest part of the pieces that make up sunlight, also known as the electromagnetic spectrum. These particles travel in waves, which are categorised depending on their length and strength, as well as how much energy they emit. Rule of thumb; the shorter the wavelength, the more energy it emits. Some of these wavelengths are visible to the human eye, others (like those evil UV rays that fry our delicate Irish skin) aren’t. Within the electromagnetic spectrum, you’ll find red, orange, yellow, green and (our friend) blue light. Because it’s visible to the human eye, is short and emits a high amount of energy, blue is known as HEV (high-energy visible) light. Impressively, it accounts for one-third of all visible light.

Sunlight is also important for us humans, as it regulates our internal body clocks, known as our ‘circadian rhythm’. It’s no coincidence that the entire species sleeps during the night, and is (relatively) full of beans by day. We’re actually pre-programmed to do so, along with many animals, plants and fungi. If you’ve ever worked a night shift, pulled an all-nighter studying for an exam, or well, just stayed out on the absolute sesh, you’ll know just how tough it is to recover. Hangover of death aside, you’ll likely find it difficult to get to sleep the next day, waking up disoriented and maybe even unable to sleep when night approaches. This is because our bodies naturally feel tired at night. Once the sun sets, our eyes send a signal to the brain, which in turn releases a hormone called melatonin from our pineal gland. Melatonin makes the body start to feel sleepy, so in the hours after sunset, you’ll notice yourself starting to yawn, stretch, and generally have a serious hankering for the leaba.

As well as contributing to DES, blue light could also be playing havoc with our melatonin levels. As mentioned above, we humans are essentially at one with nature - naturally resting when the sun sets, and waking the next morning feeling refreshed and ready to start the day (give or take a couple of skinny oat frappuccinos). However, if you consider the amount of blue light we take in these days via various digital devices, it stands to reason that our body clocks might become a tad confused. Studies like thisin fact claim that exposure to blue light “drastically disrupts the continuity of sleep”. One particular sin we’re all guilty of is picking up the phone after climbing into bed. We tell ourselves it’s just one final check for likes on that Insta we posted earlier (I mean c’mon, we looked hella cute). But somehow, two hours of scrolling passes before we finally lay down our head. Ever experienced any of these: inability to fall asleep even though you’re tired, waking in the night, frequent tossing and turning, waking in the morning feeling exhausted? If so, it’s possible that an overexposure to blue light is disrupting your natural sleep cycle.