As you may well have experienced yourself, the symptoms of anxiety are not hard and fast. They can be any or all of those already described as part of the fight-or-flight response. The more severe the anxiety, the more numerous the symptoms may be.
But different people may be particularly aware of some symptoms rather than others - for instance, sweating hands, quick breathing, a plummeting feeling in the stomach. Some people may have a 'racy' feeling throughout their body or a strong desire to urinate or have a bowel movement.
What defines the feelings as anxiety, however, is a sense of dread or fear.
But, wait a minute. Imagine yourself as young and single. Maybe you are young and single. Or maybe you have to dig back into your memory a bit. Whichever it is, cast your mind back for a moment - what was it like when you first set eyes on someone you were attracted to who was also clearly attracted to you? And how did it feel when you waited to go on your first date with someone you were extremely keen on? Did your heart thump a bit faster? Did you have mild palpitations? Were there butterflies in your stomach? Or did your hands feel annoyingly clammy?
Yet those were good feelings - ones we associate with excitement or pleasant expectation. These are the kinds of feelings we have whenever we are about to experience something we find enjoyably emotionally arousing: for some people, that might include hurtling down a water slide; for others, it could be singing a solo in the dramatic society's play or taking a penalty kick.
If we don't enjoy those particular activities, however, the physical sensations will be the same, but, because they are accompanied by fear or dread, we will experience them as anxiety.
How we interpret our bodily sensations is, therefore, a large part of how we experience them and record them in our memory. An ingenious experiment, in which young men were asked to cross a long, narrow suspension bridge made of wooden boards and wire cables that rocked and swayed 230 feet above the Capilano River in North Vancouver clearly demonstrated this.
A young woman researcher approached each of the men in turn to ask if they would mind completing a survey and, after they had done so, she gave them her telephone number and offered to explain the project in greater detail, if they called. She approached some of the men while they were crossing and others after they had crossed. It was found that the men she approached while they were crossing the bridge were more likely to call her.
Why? Because they were experiencing physiological arousal that they would normally have identified as fear. But, because they were being interviewed by an attractive woman, they mistakenly identified their arousal as sexual attraction.
So, unless we are talking about a truly terrifying situation, in which our fight-or-flight response automatically operates at full throttle, we do have some degree of choice about how we interpret or react to fight-or-flight symptoms.
A daunting activity, such as giving a talk or taking an exam or perhaps entering a party, can be less paralysing and anxiety inducing if we treat it as a challenge instead of a threat.
For the whole point of the fight-or-flight system is to get us ready to do something and, by doing it, we disperse the anxiety.
Most of us are probably familiar with the feeling of relief, or even euphoria, that may surface after we have successfully achieved something that we were really nervous of attempting.
At this point you may well be thinking, 'if only it were that easy to change how we think!' Because it isn't always, is it? However, there is a very good physiological reason for this: our emotions come first.
Once we understand what is going on - that we react emotionally, before we think - we can start to master it, and changing how we think becomes much, much easier.
Continued in this article: The powerful emotional brain
In a small number of cases, anxiety symptoms can be triggered by a physical condition, such as heart and lung irregularities, an undiagnosed thyroid disorder, inner ear disturbance and epilepsy. Drinking coffee or other drinks containing caffeine can make some people edgy and anxious. Equally, suddenly cutting out caffeine can have the same effect. So can suddenly stopping drinking alcohol or suddenly stopping taking tranquillisers.