3. All these bright screens are screwing up your sleep cycle
The explanation: Neuroscientists believe that the light from phones, tablets, and computers is suppressing the production of melatonin, the sleep hormone.
We, as humans, haven't truly evolved to deal with the sleep schedule that artificial light allows us. In the past, when night fell, the brain secreted melatonin, which tells our bodies it's time to shut down for a few hours. Light suppresses this, though—our brain thinks it's still the daytime, no matter where the light comes from.
That means that checking your mobile tech before bed convinces your brain to keep you awake. And lack of sleep can lead to depression, cognitive troubles, and starting a fight club. None of which are good for you.