Trouble sleeping lately? The fault could lie with your e-book app.
A number of studies (this one, for example) have shown that smartphones and tablets can interfere with your sleep cycles. That's because they emit blue light, which signals your brain that it's time to wake up, not shut down.
Oyster, an e-book subscription service often referred to as "Netflix for books," just updated its Android and iOS apps to help combat this problem. Its new Lumin technology reduces the amount of blue light produced by your screen, and does so automatically based on the time of day.
According to Oyster, peak reading times (for users of its app, anyway) occur between 9 and 10 p.m. -- right before bed for most folks. And while blue light (which is found in sunlight) is helpful during the day, "exposure to [it] in the evenings has been shown to suppress the production of melatonin, which helps to regulate your circadian rhythm."
Oyster's apps now gradually filter out blue-light emissions as the day turns into night. As you can see in the accompanying animation, your white background shifts to an amber color.
Again, this occurs automatically based on time of day and your location, but you can also manually adjust the settings if you prefer.
Though I don't recall seeing this option in any other dedicated e-reader app (your move, Amazon), there are numerous blue light-filtering apps available for Android (Twilight is a popular one) -- and they reduce the blue for everything you do on your phone or tablet, not just reading.
However, a search for "blue light filter" in Apple's App Store produces just one relevant result: a poorly rated browser that offers filtering only within that app. I'm not sure why there aren't more iOS options for this.
Thus, for iPhone and iPad owners who love to read before bed, Oyster would appear to have the only sleep-friendly option. (If you know of another, by all means share it in the comments.)
The service costs $9.95 per month for unlimited e-books, andfor books you want to purchase outright.