You cannot sleep properly. One reason. Technology They Suppress Melatonin. The blue light emitted by screens on cell phones, computers, tablets, and televisions restrain the production of melatonin , the hormone that controls your sleep/wake cycle or circadian rhythm . Reducing melatonin makes it harder to fall and stay asleep. Most Americans admit to using electronics a few nights a week within an hour before bedtime. But to make sure technology isn’t harming your slumber, give yourself at least 30 minutes of gadget-free transition time before hitting the hay. Even better: Make your bedroom a technology-free zone—keep your electronics outside the room (that includes a TV!). They Keep Your Brain Alert. It may seem harmless to knock out a few emails before bed or unwind with a favorite movie, but by keeping your mind engaged, technology can trick your brain into thinking that it needs to stay awake. And if you’re surfing the web, seeing something exciting on Faceb...