Reading that e-book in bed may seem like the perfect way to relax before sleep, but it might actually be harming your health.
Researchers from Harvard Medical School in Boston, USA claim that reading back-lit ereaders before bed leads to poorer quality sleep. This is due to our natural body rhythm, which uses light to tell the time.
The blue light emitted from tablets, smartphones and LEDs disrupts this pattern, meaning we experience poorer sleep, less deep sleep, and awake in the morning feeling more tired.
Researchers analysed the production of the sleep hormone melatonin in the 12 test subjects, discovering that the amount was reduced by reading an e-book.
"Overall, we found that the use of portable light-emitting devices immediately before bedtime has biological effects that may perpetuate sleep deficiency and disrupt circadian rhythms, both of which can have adverse impacts on performance, health and safety," Read the report published in the Proceedings of the National Academy of Sciences.
However it appears that iPads were used for the study, suggesting that front-lit devices like the Kindle Paperwhite are still fine to use.
So if you want to nod off faster, you're probably better off using an ereader that isn't back-lit, or just sticking with a paperback.