As technologically advanced as we are, we still rise and sleep with the sun like our caveman ancestors. This repetitive 24 hour process is known as a circadian rhythm. When we use our devices after dark the light emitted tricks the body into thinking it’s still light outside and reduces the production of sleep inducing melatonin that darkness stimulates.
The Kelvin scale measures light tone on a scale from yellow, 1,000, to blue, 8,000. iPhones and iPads are approximately 7,000 on the scale. By contrast relaxing candlelight measures 2,000.
Electronics manufacturers know that the blue light our devices emit can keep us up at night. They have now started to include settings to counteract this. On iOS the Night Shift, Night Mode on Android, settings allow you to switch to a more yellow tone at a set time during the day. It is recommended that you set it at least 90 minutes before you plan to fall asleep. Mine is set for 9:30 PM to 6 AM. You could even set it to match the sunrise and sunset time in your area. Ah, the wonders of technology!