What physiological change may indicate an overstimulated infant?

The physiological change that indicates an overstimulated infant is the presence of color changes and vomiting. When infants are overstimulated, they may exhibit signs of distress through various physiological responses. Color changes can occur as a result of increased stress or discomfort, where the infant might appear red or pale, indicating heightened arousal or an inability to cope with the sensory input they are experiencing. Vomiting can also be a sign of over-stimulation as it reflects the infant's struggle to manage stress and may be a response to an overload of sensory stimuli. These symptoms serve as important indicators for caregivers and healthcare providers to reassess the infant's environment and adjust stimuli accordingly to promote calmness and comfort.

In contrast, an inability to fall asleep often indicates different issues, such as discomfort or hunger, rather than simply overstimulation. Excessive sucking reflex can be a normal behavior in infants related to feeding and comfort rather than an indication of overstimulation. Lastly, a calm and relaxed posture typically suggests that an infant is well-regulated and not overstimulated at all, as they are able to manage their sensory experiences effectively.