We might want to drown it out in light, but, as Aleks Krotoski discovers, darkness can be good for us. Electric light tampers with our circadian rhythms. Now we can light up any part of the day, our body isn't shutting off to sleep as easily as it once did. Aleks discovers the way that technology is starting to recognise this on both a personal level and a societal level.

Produced by Victoria McArthur.