We all know by now that to procure the coveted seven to nine hours of shut-eye each night, we need to lower the thermostat, banish screens from the bedroom and give ourselves a little mindful wind-down time before turning off the lights. But do we actually abide by these scientifically proven sleep rules? The National Sleep Foundation, a non-profit that has monitored America's sleep habits since 1991, recently debuted its inaugural Sleep Health Index to answer this exact question.