Since the dawn of time, humans have been functioning on the same internal clock: sleeping at nighttime and waking during daytime. In recent history, advances in technology have affected the way we sleep. The reason for this is due to the devices we use late at night.
The body uses light as a signal for whether or not you should sleep. When your eyes sense light, the brain gets a signal to wake up. At night, your body produces melatonin, which is a hormone responsible for the tiredness and sleepiness associated with nighttime. The color of the light is also pretty significant: during the daytime, light has a blue color associated with it (hint: the sky); during sunset, the light takes a more red hue.
Your smartphones and laptops are not designed with your biological clock in mind. This means that they will emit a strong blue light in the dead of night – sending signals to your body to wake up. This greatly hinders your biological clock, which results in longer late nights, shorter amounts of sleep, and all the negative consequences associated with a lack of sleep.
However, this does not mean that one should boycott technology completely. If you are one who does not work extensively with colors, you should check out the application for both PCs, Macs, and iPhones (sorry Android users) called f.lux. F.lux (pronounced as flux) is a powerful app that alters the color hues on your laptop to match those of the natural light cycle. In other words, during the day, the laptop would appear to be normal; at sunrise and nighttime, the laptop will have a strong red hue to it.