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Blue Light: Better Than Coffee?

For years now, across multiple posts here on Mark’s Daily Apple, nighttime blue light has gotten a pretty bad rap. Although I’ve mentioned that blue light [1] during the day is important (and natural sunlight is helpful), I haven’t focused on it, mostly homing in on the circadian-disrupting, sleep-inhibiting, melatonin-blunting effects. As a result, many of you may be entirely unaware of the potential positive, beneficial applications of blue light. Recent and not-so-recent research has confirmed that blue light can actually improve our cognitive abilities, including memory, alertness, reaction time, and executive function – at least in the short term.  Oh, and it doesn’t always ruin our sleep. It might even improve it if you expose yourself at the right time.

Wait a minute – blue light is good for us? Sisson, you just got done spending the last few years telling me to excise blue light from my vicinity at night if I wanted a good night’s sleep [2], and now you’re saying we might actually need more blue light. What gives?

Easy. Context is everything. Blue light at night can have a negative, inhibitory effect on our sleep [3] onset and sleep quality because it signifies daytime to our suprachiasmatic nucleus, that region of the hypothalamus that sits near the optic nerves and regulates our circadian rhythm according to the light we perceive. But during the day – you know, when blue light naturally bounces around the atmosphere into our eyes – it’s beneficial because presence of blue light matches up with our bodies expectations. Blue light isn’t “bad,” in other words. It’s bad in the wrong context. In the right context, which is daytime, blue light promotes restful, satisfying nighttime sleep [4].

And for the exact same reasons blue light is bad for melatonin secretion and sleep physiology when we’re exposed at night, it also provides a boost to cognition. The bulk of the blue light research may focus on its inhibitory effects on melatonin and sleep, but a growing body of study is realizing that those same inhibitory effects seen at night can be used to improve alertness, executive function, memory, and other aspects of cognition. What’s negative at night when you’re trying to sleep is helpful or even essential when you’re trying to get work done. Blue light may very well be better than (or at least equal to) caffeine [5].

Let’s look at a few recent studies to see how we might use blue light to our advantage.

Not bad, eh? Makes a guy want to step outside and get some fresh air. Or, barring that, stare straight into an LED bulb.

Things to keep in mind when applying these results to your workday:

So, in the end, blue light isn’t a villain. It’s just misunderstood (and misapplied).

How are you going to use blue light to your advantage? Or are you already doing so?

Thanks for reading, folks. See you next time.