Working on the computer at night is bad for your circadian rhythm – the reason being that the body thinks it is day when it is night. Enter f.lux … (h/t EMI)
Apparently (and certainly overly simplistic) there are a number of sensors in the eye that determine the time-of-the-day. Those sensors then influence the serotonin levels, and this in turn impacts your circadian rhythm (work and play during the day; sleep, repair …and play maybe… at night). So of course if those sensors get it wrong, all kinds of things can go wrong, essentially leading to a bad night’s sleep, and therefore to less repair of the body, which can lead to illness, weight gain, whatever.
What does those sensors react to? First and foremost, light. Nothing much you can do about this (apart from turning the light down a bit at night). But also: the temperature of the light – during the day, the light is bright and blue’ish, which is called a high color temperature. In the morning and in the evening the light is much “colder” (in the color temperature sense). And of course at night in front of the fire the color temperature is the coldest.
What’s the issue with the computer? Well, the color temperature of a normal computer screen is pretty much mid-day light, meaning that white parts of the screen have the same color profile as a white piece of paper at mid-day. Ergo the sensors think it is midday, hence the impact of the computering at night on the circadian rhythm.
Enter f.lux, a nifty little tool that changes the color temperature of your screen to match that of the ambient light, ie whites are adjusted to be at the color temperature chosen, and all other colors are adjusted accordingly. The color temperature can be chosen 2700K and 6500K, covering quite a bit of way. There are also pre-sets for tungsten, halogen and flourescent light.
So at night sitting in front of the computer screen mimics the ambient light, and hence at least the situation is not worse than, say, reading a book or doing really whatever in an artificially lit environment.
My only criticism is that the program is a bit over-engineered: it looks at your location, and then automatically adjust depending on sunset. This is nice, but not particularly helpful – I’d rather have the option to invoke it manually. So if I am in a room without windows for example I can still use it, and make my computer match the ambient light, regardless of the time of the day.