The Blue Dilemma 

The Sun’s light is incredibly influential in our lives. Aside from providing almost all of our energy, it has another effect: our bodies use light intensity as a cue for our internal body clock. Being exposed to bright light in the morning helps our bodies to wake up and become energised, while the dimmer light at night-time tells our bodies to start winding down and sleep. Receiving the right amount of light at the right times of the day is critical for our wellbeing, because it helps regulate our alertness, our mood, our productivity and our sleep patterns. 

Our daily cycle is largely controlled by a hormone called melatonin, which is produced by the brain at night, in the dark. People who don’t produce enough of this hormone take longer to fall asleep. Bright light suppresses its production, so when we’re exposed to bright light at night—like a TV or computer screen—this can decrease our levels of melatonin and mess up regular sleep patterns. 

Clearly, the answer isn’t to revert to medieval times and go to bed at dusk; we can find ways to cope. See, the extent of our body’s response to light depends on a few of things: how bright the light is, how far the screen is from our eyes, and what colour is being emitted. Crucially, not all colours have the same effect on your body. Blue is the most disruptive wavelength, because it’s the most powerful in decreasing melatonin levels. Blue wavelengths suppress melatonin for almost twice as long as green wavelengths. 

That’s a bit of an issue, because most screens are backlit by blue light. 

So, what can you do? Well, you could avoid looking at screens for a couple of hours before bed, but let’s be real, that’s not going to happen. For a lot of people (including me), computers are the tool of their trade and they have to work on them until late. Instead, you could dim the brightness of your screen, or you could find a way to filter out the blue wavelengths. 

A couple of years ago, a friend clued me into this neat little program called f.lux. It adjusts the colour of your screen to become progressively yellower as the sun sets, so in the hours before you go to sleep, you’re exposed to less and less blue light. I’ve been using it for about three years and it’s really helped—you can download it here if you want to try it out!