Technology is rapidly changing the world and how we live our lives, but not all the changes are good. Increasingly, we are exposing ourselves to the blue glow of electronic devices such as computers, smartphones and tablets, and this is having profound biological effects. A new study in the Proceedings of the National Academy of Sciences shows this light is affecting our sleep patterns, especially if these devices are used within four hours of bedtime. Affecting sleep patterns is a serious matter.

Poor sleep can have a profound effect on the internal working of the human body. The activity of hundreds of genes can be altered, changing the body’s chemistry. Heart disease, diabetes, obesity and poor brain function have all been linked to substandard sleep. Sleep is critical to the body’s repair function. Sleep affects inflammation and immunity.

Blue light emissions from e-readers, laptops, LED monitors and smartphones reduce melatonin levels. Melatonin is a hormone that helps to induce sleep and also protects against breast, colorectal and prostate cancer, as well as reducing obesity and diabetes. People using these devices prior to sleep take longer to fall asleep and spend less time in the restorative REM sleep. They are also sleepier and less alert the following morning, even if they have had a full eight hours of sleep. It would be a good idea to not use these devices within four hours of bedtime.