The degree of accompanying stress response and its physiological, psychological, and emotional changes are directly proportional to the degree of anxiety. For example, if you are only slightly concerned, such as being slightly nervous about meeting someone new, the body produces a small degree stress response. The small degree stress response can be so slight that you don’t even notice it.
Your heart beats fast, and your breathing speeds up. Your chest may feel tight, and you might start to sweat. If you've ever felt it, you know that anxiety is just as much a physical state as a mental state. That's because there's a very strong biological chain reaction that occurs when we encounter a stressful event or begin to worry about potential stressors or dangers in the future. Other physical symptoms include sweating, headaches, and insomnia. Psychological symptoms may include feeling restless or irritable, feeling tense, having a feeling of dread, or experiencing ruminative or obsessive thoughts.
An evolutionary psychology explanation is that increased anxiety serves the purpose of increased vigilance regarding potential threats in the environment as well as increased tendency to take proactive actions regarding such possible threats. This may cause false positive reactions but an individual suffering from anxiety may also avoid real threats. This may explain why anxious people are less likely to die due to accidents.
There are two very important guidelines to think about, aside from symptoms. These are duration of symptoms and level of impairment. Anxiety is a normal reaction to stressful situations, and even high levels of anxiety can be healthy and beneficial at times. Disorders are only present when anxiety symptoms last for several weeks to months and significantly interfere with every day function or cause long-lasting distress.
Occasional anxiety is an expected part of life. You might feel anxious when faced with a problem at work, before taking a test, or before making an important decision. But anxiety disorders involve more than temporary worry or fear. For a person with an anxiety disorder, the anxiety does not go away and can get worse over time. The symptoms can interfere with daily activities such as job performance, school work, and relationships.