Sleep is defined as a state of rest that is opposite to being awake. Physiological sleep is characterised by REM and NON-REM stages. Deep sleep is experienced during the REM stages, when you enter the oneiric stage. Sleep problems are very common; if persistent, they can negatively affect daily activities, altering psycho-physical wellbeing. Stress and anxiety are common factors that may accompany these problems also affecting the quality of sleep.