Using a computer or tablet in the late evening could disrupt the body’s melatonin production. Mariana Figueiro of the Lighting Research Center at Rensselaer Polytechnic Institute and her team showed that two hours of using an iPad at maximum brightness was sufficient in suppressing people’s normal nighttime release of melatonin, a hormone that controls the body’s clock or circadian system. Melatonin tells your body that it is night, helping you go to sleep. If you delay that signal, sleep gets delayed and after many years, it could lead to a disruption of the circadian system causing serious health consequences. Figueiro emphasizes that the dose of light is important, the brightness and exposure time determines whether it affects melatonin. Light in the blue-and-white range that tablets emit will disrupt people’s melatonin levels. The researchers designed light-detector goggles and had subjects wear them during late-evening use. Light dose measurements from the goggles correlated with the decreased melatonin production. The benefits of this is that a morning shot of screen time could be used as light therapy for seasonal affective disorder and other light-based problems Figueiro hopes that manufacturers will “get creative” with tablets, making them more “circadian friendly”. In the meantime, simply avoid extensively using your tablet before going to sleep.