The term "cortisol awakening response" refers to the natural increase in cortisol levels that occurs in the body upon waking up. This response is important for regulating the body's stress response and maintaining overall health. Some synonyms for this term might include "morning cortisol surge," "dawn cortisol spike," or "awakening cortisol boost." Other related phrases could include "cortisol awakening effect" or "cortisol morning peak." While there are slight variations in the language used to describe this phenomenon, all of these terms refer to the same crucial process that helps us start our day off right.