Blue light is the blue part of the spectrum that signals to our circadian cycle that it is now daytime.
Exposure to blue light in the evening and night hours can prevent sleep.
Blue light is amply emitted by electronic devices.
Here is what to do:
1) Reduce usage of electronic devices in the evening, and, if possible, eliminate it at night.
Eliminating work-related usage will have the added benefit of letting the nervous system calmly slide toward a sleeping mode.
2) If not possible, or if a gadget is used for a relaxing activity like reading, we recommend installing apps that allow you to control or eliminate blue light, such as F.lux for desktops or Night Shift for phones.