Anticipatory anxiety is anxiety that is felt prior to, or in anticipation of, an event that has previously caused one to become anxious. Many people experience this type of anxiety anxiety, and the anticipation is often worse than anything that may have occurred at the event anyway. Anticipatory anxiety may be a precursor to a panic attack, or it may be part of a larger anxiety disorder, but sometimes it just occurs on its own without any feasible explanation.
Some people experience anticipatory anxiety prior to events or activities they have never done before; the unknown becomes more fearful than the known. For instance, if one is preparing to give a speech in front of a large crowd, one might experience anticipatory anxiety whether or not they have ever experienced it before. Usually, once the speech starts and things go well, the anxiety will fade.
When anticipatory anxiety acts as a precursor to a panic attack, it can actually be beneficial. Some people develop the ability, through therapy, to recognize the signs of a panic attack and to stop it in its tracks. There are a number of strategies that may be used in order to deal with anxiety, and to prevent it from causing distress or detriment to one's life.
Some people find that they are able to talk themselves out of their anticipatory anxiety with logical reasoning. For instance, if one is anxious about going to the doctor, one might remind themselves that they exercise and eat right, and everything should be just fine. If one is nervous about giving a speech, one might remind themselves that they worked hard on their speech, they know their material, and that they are ready. By the same token, one might remind himself that he has done something challenging before, and that it went well.
Some people find that keeping it simple, and just thinking "Stop!" to themselves the moment their anxiety occurs can help the brain to stop a destructive thought pattern. Refusing to think any "what if" questions is another way to prevent anxiety. Deep, diaphragmatic breathing and other relaxation techniques such as stretching are other ways to stop anticipatory anxiety from worsening.
Keep in mind that anticipatory anxiety is a normal response to an unknown or stressful event, and does not necessarily signify a problem. Most people experience this feeling on occasion. If the anxiety begins to interfere with one's life, and prevent one from doing something important, or trying new things, it is time to seek help. A professional will be able to offer advice regarding therapy and medication, both of which can help to combat anxiety.