We hear different recommendations on how much sleep we should get each night so frequently – some teachers tell us we need 9 hours, our friends tell us that they need 6 hours, and some of our parents tell us that we need 8 hours. Experts generally, in the past, recommended seven to nine hours of sleep per night for healthy adults; however, several sleep studies found an exact amount of sleep that is most optimal. Seven – not eight – seems to be the magic number when it comes to sleep and cognitive health. Getting too much sleep is associated with health problems (including diabetes and cardiovascular disease.) Though an overwhelming amount of evidence points to seven hours as the optimal sleep duration per night, scientists are still not all in agreement. Some believe that the optimal amount of sleep is however much your body can take – that is, without an alarm clock or external stimuli to wake you up.