According to Dr. William Dement, Sleep Debt is created when personal sleep requirements are not met. This is especially true of students, medical residents, busy executives, shift workers, new parents, as well as most of the remaining population. In Sleep debt, there is the bad and good news - the bad news is that Sleep Debt accumulates, builds quickly, and does not decrease spontaneously, while the good news is that the old adage "You can't make up lost sleep" is not true. Repaying Sleep Debt requires extra-over and above the usual requirements. In most cases, Sleep debt has a natural way of resolving itself. The homeostatic relationship between wakefulness and sleep discourages normal people from becoming dangerously sleep deprived. The body reacts to a lack of sleep by having daytime drowsiness such that an intense desire to sleep induces the person to either go to sleep early or sleep in late.