Anxiety is used to describe feelings of worry, fear and unease. Typically, it incorporates both the emotional and physical sensations we experience when worried or nervous. Anxiety is related to the 'fight or flight' response and, while unpleasant, this is a normal reaction when our body perceives a threat.Anxiety symptoms. While feeling anxious is a natural response, suffering from anxiety long-term can be very intense. However Anxiety can affect individuals in a different way.