When our brain receives information from our senses, the amygdala, which lives in the ancient limbic/emotional part of the brain and is sometimes called the “Guard Dog” of the brain, assesses whether it is a threat by recognising the feelings it evokes. If it sees something as a threat, for instance, we may be encountering a barking dog and have been frightened by a dog as a child, it then releases a chemical mix that enables us to fight or flee. This causes a physiological response, sending blood to muscles, releasing sugar to increase energy, heart rate and blood pressure increase ready to fight or flee and digestion shuts down. At the same time, the amygdala inhibits the ‘slow thinking’ rational brain resulting in a response that isn’t thought through and is based on emotions and feelings. The effect of stress then is that we loose our ability to think clearly, reason and make decisions. Short-term memory is also affected and we can feel much more emotional. This is often called an “amygdala hijack” where the amygdala hijacks the rational brain.