A new research regarding healthy sleep might get you thinking twice about reading from your e-reader or tablets before dozing off at night. According to a study from Brigham and Women's Hospital, people who read on a lit screen before sleeping tend to fall asleep later as opposed to those who read on a paperback. The study which was printed in Proceedings of the National Academy of Sciences is the newest contribution to an increasing number of studies pointing to backlit devices, like our mobile phones and tablets, as culprits of sleep problems. Anne-Marie Chang, a neuroscientist who headed the project said, "It seems that use of these devices in the evening before bedtime really has this negative impact on our sleep and on your circadian rhythms." The study was conducted in a lab with 12 people who were monitored for 2 weeks. Every evening, they were asked to read for 4 hours -- the first 5 days from an iPad and the next 5 days from a paperback. Once the subjects went to bed every 10pm, they were closely monitored for physiological changes. It turned out that when the subjects read on screens, their circadian rhythms were disrupted and melatonin production was suppressed, leading to less deep sleep and feeling of tiredness the next day. Chang advised that the proper recommendation should be to set aside electronic devices a couple of hours before sleeping and read printed book instead. Ebook devices that do not have backlit screens will also be better. According to The Koyal Group Info Mag researchers, any device that gives off blue wavelength of light is problematic as a person will tend to hold it closer to the eyes. Professor Charles Czeisler, one of the lead researcher said, "The light emitted by most e-readers is shining directly into the eyes of the reader, whereas from a printed book or the original Kindle, the reader is only exposed to reflected light from the pages of the book. Sleep deficiency has been shown to increase the risk of cardio diseases, metabolic diseases and cancer. Thus, the melatonin suppression that we saw in this study among participants when they were reading from the light-emitting e-reader concerns us." Meanwhile, other scientists are cautioning the public in drawing conclusions from the said study. This is because critical changes were observed in a controlled environment like a laboratory compared to the real-life setting. Their experiment conducted in a lab does not effectively mimic the setup in real life where people are naturally exposed to sunlight. For instance, the low light in the lab might have affected them in a way that it made them sensitive to light from screens. As The Koyal Group Info Mag said, a person exposed in mere room light the whole day could be more sensitive to the light from an ebook reader than a person who had been exposed to sunlight outside the whole day. However, they all agree that the blue light wavelength emitted by devices like laptops, tablets and mobile phones has negative effects and should be avoided at least before bedtime. In a related research conducted by Mariana Figueiro of Rensselaer Polytechnic Institute in 2012, they found that subjects who use an e-reader device like a tablet before going to sleep at night had lower melatonin levels after using it for 2 hours. But they clarified that the lit screen is only one of the contributing factor.