Printed books help you sleep better – and could cut risk of cancer

More and more these days, we hear how reading a device such as a mobile phone, tablet or e-book before you go to sleep at night, not only keeps you awake, but also gives you a poorer quality of sleep when you do finally nod off.

And there are even worse side-effects. 

But we also know the healthier solution – read a printed book at bedtime. (Or printed magazine, perhaps?)

According to a recent study by Harvard Medical School, healthy young adults were tested by alternatively asking them to read a light-emitting e-book and a printed book, within one hour before their bedtime.

The quality of their sleep – and the quality of their experience the next day – was then measured.

Those reading the printed book fared significantly better.

When the participants read the e-book at bedtime, they took longer to fall asleep, saying they felt less sleepy, compared with the other evenings when they read a book.

Significantly however, they also experienced sharply reduced mental alertness the next morning, saying it took them many hours longer to “fully wake up” than when they had read a printed book the night before.

According to the researchers: “These results indicate that reading a [light emitting] e-book in the hours before bedtime likely has unintended biological consequences that may adversely impact performance, health, and safety.”

Reading e-books at night delays a person's “circadian clock” and suppresses levels of the sleep-promoting hormone melatonin, the researchers say.

They add: “The results of this study are of particular concern, given recent evidence linking chronic suppression of melatonin secretion by nocturnal light exposure with the risk of breast, colorectal, and advanced prostate cancer associated with night-shift work, which has now been classified as a probably carcinogen by the World Health Organisation.”