Blue Light, Sleep, and Performance

I’ll attempt to explain the relationship between blue light and sleep, specifically how blue light from your smartphone, tablet, laptop, monitor, and TV can make it difficult for you to sleep at night. We all know sleep is important, but it’s a lot more important than we think.

Want to be at peak performance when you’re studying? Working? You need sleep. And not any kind of sleep will do: you need both good quality and decent quantity. Working backwards: to be at your best you need good sleep, and to sleep well you need to limit yourself from all those gadgets I mentioned above that emit blue light at night.

This will be quite technical at first, but only at first, so bear with me. I’m paraphrasing from Wikipedia. Melanopsin is a photo-sensitive pigment, found among ganglion cells in our retina. Melanopsin is sensitive to short-wavelength visible light and reach peak light absorption at 488 nanometers (nm), which is within the blue light spectrum of 450-495 nm.

Melanopsin has a direct communication link to a particular area of the brain called suprachiasmatic nucleus or SCN. The SCN can be thought of as our biological clock, and controls our circadian rhythm. This makes sense: our eyes tell the brain when it’s dark and our brain tells the body to sleep. If you spend a lot of time looking at displays at night — most displays use blue LED as the light source — the chance of disrupting your normal biological circadian rhythm is high. Here’s a simpler way to put it: if you stare at displays at night there’s a good chance you’ll not be sleeping well. But sleeping well is important for your health as well as for your performance (no, not that kind of performance, though you may see improvements there too).

Sleep Deficit: The Performance Killer” is an old Harvard Business Review article from 2006. The title is crystal clear: If you don’t sleep well your performance at work will suffer.

According to WebMD this is how sleeping poorly on a regular basis affects your brain: reduced attention and concentration, reduced reaction time, reduced decision-making and memory capabilities. Exactly the things you don’t want to happen when you’re trying to achieve excellence.

When the sun goes down, put down your smartphone, put the computer to sleep, and instead of watching that movie or TV show, turn off your energy-efficient LED lights, and get ready to go to sleep. Your body and your brain will thank you for it. And when you wake up you’ll be more ready to tackle your day.