Another problem with kids screen time, and the one app that can solve it

Most apps keep you up at night, but f.lux helps you sleep

Light is the most important signal your body uses to know when to go to sleep and when to wake up. When it's dark at night, your brain produces a hormone called melatonin. Melatonin helps make you sleepy, and also helps fight against some cancers. When you are exposed to bright blue light at night, your brain can't make the hormone, and that can make it take longer for you to fall asleep. Sleep is essential to health, so anything that keeps people up at night is a public health concern.

Most of us use computers, tablets, and smartphones at night, exposing ourselves to the bright, blue light that keeps people awake. A very clever free program called f.lux has been developed to hopefully help reduce this problem, by cutting the amount of blue light we are exposed to at night. At sunset, f.lux changes the white balance of your screen, so for a minute or so everything seems orange:

f.lux works by reducing the amount of blue light your screen emits

But your brain is designed to adjust to changes in color throughout the day, so you very quickly get accustomed to the warmer light. In fact, if you switch back to the standard setting, then everything will at first appear to be weirdly blue:

After a few moments, the f.lux screen will look "white" and
if you switch back the standard setting will now look cold

By installing the program, you will reduce your exposure to blue light at night. That might help you sleep better, and could potentially improve your long-term health. It's free, so you should install it on your computer, tablet, and smartphone right now!


If you're a first time visitor, this blog is about the Loss of the Night app and citizen science project. In brief, we need people living big cities to tell us how many stars they can see (no stargazing experience necessary). But the blog also occasionally has other stuff related to light at night, for example photos of good and bad street lighting from around the world, and this calendar of moon phases for 2014.


Additional notes:

1) I am not aware of any study that examines to what extent f.lux reduces the melatonin suppression caused by looking at a screen. It's basically a band-aid for the societal problem of improper light exposure. If you really want to sleep better and live longer, spend as much time as possible outside during the daytime (even if it's cloudy), and avoid bright white lights at night.

2) Some tasks (such as editing the color balance of a photo) should probably not be done with f.lux turned on. You can temporarily disable f.lux for one hour with just two clicks.

3) I have nothing to do with f.lux, and I don't know the people who created it. But I study light at night, and I am just doing my part to spread the word about this great program.

4) Have friends that have trouble going to bed at night? Tell them about f.lux!