States of Arousal During Infancy

States of arousal describe an infant’s physiological and behavioral condition during the daily cycle of sleep, wakefulness, and activity.

These arousal states are controlled by an internal clock known as the circadian rhythm.

During infancy, there are five arousal states: regular sleep, irregular sleep, drowsiness, alert inactivity, and waking activity.

First, infants during “regular sleep” keep their eyes closed and breathe slowly and regularly. They remain still without making major movements.

Next, during “irregular sleep,” the eyes remain closed, but infants show rapid eye movements. They breathe irregularly and show muscle twitches.

The third state is “drowsiness,” in which infants may open or close their eyes and breathe irregularly. They make slight body or limb movements.

Fourth, during “alert inactivity”, infants keep their eyes open and breathe evenly. They also quietly observe their surroundings.

Last is the “waking activity” state, in which infants keep their eyes open and breathe irregularly. They make strong, active movements in response to stimuli.