Using eReader, Tablet, Laptop, Smartphone at Bedtime Can Cause Breast Cancer, Prostate Cancer

Thursday, January 01, 2015 – A recent study conducted by scientists of Brigham and Women’s Hospital in Boston, shows that uses an eReader, laptop, smartphone, or certain TVs before bed has negative effects on sleep as well as longer-term health.

People love using computer at bedtime, but according to this study, to enjoy a good night sleep and a healthy living, it is necessary to not use computer and other e-readers which emit powerful LED light, at least before bed. These are the findings of a study done on a dozen people by a team of researchers from Brigham and Women’s Hospital in BostonMassachusetts, published by the Proceedings of the National Academy of Sciences (PNAS) of the United States of America

During the study, 12 participants were chosen, and all had a mandatory bedtime of 10 p.m. and a 6 a.m. wake-up; five consecutive nights a week. They were grouped in two categories: 1 group read light-emitting device (LED) such as eReader, laptop, smartphone, or certain TVs, about four hours before bedtime. The other group was also reading but printed book. In both cases, individuals were placed in rooms in filtered natural light.

Results showed a big difference in sleep between the two groups. Participants reading on LEDs took longer to fall asleep because their brains secrete less melatonin, a natural hormone released mainly at night and promotes sleep. Thus, they found themselves more at risk of insomnia. Similarly, these individuals took more time in the morning to feel fully awake compared to individuals who read on paper.

Insomnia, Prostate Cancer Breast Cancer                                                                     

Furthermore, the study shows that prolonged reading and regular reading LED devices before bed causes a shift in the internal clock (also called circadian rhythm), a physical, mental and behavioral 24-hour cycle that tells the body when to sleep and regulates many other physiological functions. And the risks go further. The authors of the study observed that the practice, in the long term, has probably unintended biological consequences that can have a negative impact on performance, health and safety of the individuals. Persistence can lead to serious health problems such as prostate cancer and breast cancer.

A decrease of melatonin secretion may increase the risk of certain cancers. In various other studies, it has been demonstrated that a chronic decrease in melatonin secretion increases the risk of developing breast cancer and prostate cancer. Previous studies have also found a negative impact on cardiovascular functions, memory and metabolism. In fact, some recent studies have found that people who work night shifts may be at increased risk for cancer, which could be linked to melatonin levels in the body.

How is this possible?


Most smartphones, tablets and other backlight reading lights use light-emitting diodes, commonly called LEDs. These diodes emit a very bright light than ordinary lamps and especially a very large amount of blue light. However, it is present in natural light during the day but declines in the evening. It is that light which, when viewed through the lens of the eyes, allows among others to regulate the so-called internal clock. Too much blue light seen by the lens at bedtime disturb the setting of the internal clock, thus leading to insomnia, and others.

The conclusion of the researchers to sleep well and feel awake and alert in the morning, it is best to opt for the old method, reading printed book at bedtime.

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