Why is it a problem for college students to be ” rest deprived” (as well as sleep deprived)?

Why is it a problem for college students to be ” rest deprived” (as well as sleep deprived)?
The essay must quote and/or paraphrase and work directly with material from all the four essays. In addition,define and employ key terms that seem to be central to the arguments. Some key terms that might help with the argument are : mental downtime; default mode network; mindfulness training; intrinsic activity;reflection; introspection; off-line and reflective processing; high environmental attentional demands; self and social processing; task positive/task negative; and constructive internal reflection.