Memory and concentration, as well as higher cognitive performance, suffer from not getting enough sleep. This implies that if your teen studies for examinations all night, they are setting themselves up for a bad academic performance on exam day. Actually, research shows that sleep deprivation can actually impair certain types of memory formation. In addition to being mentally fatigued, sleep-deprived people tend to make more errors in judgment and may even be at increased risk for accidents. Sleep is important for learning and memory processes, and when you're tired, it's difficult to pay attention and remember what you learned during the day. However, although it is important for students to get adequate sleep, they should not allow this to interfere with their daily activities. For example, students should not study after dinner or use alcohol or drugs to stay awake. It has been shown that poor performers on sleep-deprived state testing tasks were also found to have lower levels of cortisol, the body's stress hormone. High levels of cortisol have been linked to decreased focus, increased irritability, and worse memory performance overall. Therefore, not only does lack of sleep negatively impact how well students think and act, it can also have negative effects on their physical health.