If you're an anxious person you experience a strong reaction to things in your environment that may be a threat, which results in you having a larger stress response then someone else. As an anxious person you will find it difficult to tolerate uncertainty about the future and things that may go wrong. This may be about world  events - for example, terrorist attacks or plane crashes - or matters relating to your relationship or your health. For example: "What if he doesn't really love me?" or "What if I've got cancer?"

People with an anxious personality tend to believe that the world is dangerous and that they have to be hypervigilant in case there is any potential danger to their body or their emotional well being. In their mind they are frequently thinking about the what-if's and the maybe's.

Their behavior is motivated by an attempt to reduce or get rid of the stressor that is causing them to feel stressed. For example, the anxious person may always say, "Yes" if asked to take on extra work by the boss and is thought to be obliging. It could be however, that he is anxious about being criticized or being disapproved of if he says, "No".

Occasionally an anxious personality does not even know that what he feels is anxiety. The body experiences discomfort, and often any changes to the gut or bowel, or problems with the immune or nervous system, are seen as physical problems that need to be tested and treated rather than any cognitive (thinking) processes.

Often, every anxious or negative thought (which then becomes the stressor) can cause adrenalin to rise in the body. Adrenalin is the stress chemical with the 'fight' or 'flight' mechanism in case the situation is dangerous. This adrenalin gets stored in the muscles leaving the person feeling 'on guard' in the event of any danger. This stress feeling may result in the person having an overreaction to a small event due to the build up of adrenalin already in the body. Others may be surprised by this intense reaction.

The sensitive person is often anxious and likely to be a worry-wart. The brain of the sensitive person is sensitized to threat and as a result the body produces adrenalin at the first suggestion of anything in the environment being possibly dangerous to the person. This may be from something external (heat, noise, unpleasant smells, bright lights, scratchy clothing, food with strange textures) or internal (feeling disapproved of, disliked or criticized).

Anxious people are prone to adrenalin floods - a strong physical/adrenalin response to raised voices, cross tones, any hint of conflict between people, even if the conflict does not involve that person. Anxious people may startle easily.

Adrenalin arouses the nervous feeling, which is interpreted as the anxious feeling, before the person has a realization of the situation. Once the brain recognizes the fear feeling (adrenalin arousal) it stays on guard for the danger and the thinking then is, 'what if' this and 'what if' that. The brain is trying to find a reason for the fear and will dwell on a person's vulnerability, which may at that time be about their health, finances, relationships, children, work, being disliked, being inadequate. It will always find something to justify the feeling.