Flying 18%

Death 19%

Sickness 19%

Deep Water 22%

Financial Problems 22%

Insects & Bugs 22%

Heights 32%

Public Speaking 41%

These numbers come from The Book of Lists, 1991, but it's been pretty much the same since they first started asking the question. When people are asked to list their greatest fears, speaking to a group always filters to the top.

Dale Carnegie discovered this in 1910 and built an international reputation (and a small fortune) around addressing it.

Jerry Seinfeld reportedly said of this list that it suggests that at most funerals, the guy giving the eulogy?.would rather be in the box!

Funny, unless it's you giving the eulogy. But why do you become afraid when speaking in public?

The answer is that when you find yourself in front of a group of people, your neo-cortex, which was hard wired eons ago to ?protect? you, reads the situation as the classic threat scenario of being one-against-many, and that triggers the fight-or-flight response. You do indeed feel exactly the same way you do when faced with a truly life-threatening event.

If you feel afraid when faced with speaking before a group, it's because the very same chemicals that are released when you blow out a front tire at 70 miles per hour are coursing through your veins and signaling to you that you feel afraid. When faced with the prospect of standing up and speaking in front of a number of people, three processes, intertwined with each other, actually take hold of your systems and often don't let go until well after the event that triggered them has ended.

The first thing that happens is that the well-evolved thinking parts of your brain recognize a potential threat in the situation, but because at this moment you're not hard-wired to discern between the imagined and the real, your brain errs on the side of caution and sends a clear signal to your hypothalamus, a gland located in the center of your brain.

This is the second process, where the gland begins emitting hormones to get the body prepped to deal with the threat. The signal to the hypothalamus takes milliseconds, and sometimes the brain is able to resolve the threat that started the process just as quickly, but unfortunately at this point a chain of events has started that takes considerably longer to subside.

You know how this works if you've even been startled by someone approaching you from an unseen direction who is suddenly, unexpectedly in your face. You jump, and then just as quickly realize that the person represents no threat to you whatsoever. But just try telling that to your heart. Often for minutes after the "threat" has been "resolved", you're still shaking inside, and you might even harbor somewhat ill feelings for the person who startled you, keeping your heart beating at a faster than normal rate and pounding with much more force than normal!

Fight or Flight

When the hypothalamus, which regulates most bodily functions, receives the threat signal, it sends a group of hormones to the pituitary gland at the base of your brain. This in turn releases hormones that activate your adrenal glands, which sit on top of your kidneys - a spot ideally centralized in the body to make for the shortest trip to all parts of the body for the adrenals' output: adrenaline.

Adrenaline is actually pretty cool stuff. It causes a number of responses in the body, all of which are designed to give your body the physical edge it needs to run like hell or stay and fight to the death. It starts with the heart.

First, adrenaline increases the rate at which your heart beats, speeding the process of moving blood through the oxygenating function of the lungs. Next, it increases the force of your heart's contractions, to ensure blood gets to the far reaches of your body like your fighting hands or your running feet. That's where the thump-thumps come from. All's pretty good so far.

Then, to make sure all these muscle groups are working best, adrenaline facilitates what is essentially a valving process that ensures enough blood is flowing to the motor control sections of your brain. Bit of a downside to this process, however, in that the system has to get the blood from somewhere, and finds the most convenient supplies in the thinking portions of your brain.

So just when the rational parts of your brain, which actually don't fear imminent death at the podium, want to have as much cognitive ability as they can muster, greater forces have other plans. You actually get a little dumber.

You've got the fever

If all that weren't enough, adrenaline works to speed up your metabolism as it works to turn glucose, blood sugar, into glycogen, the form of 'energy' your cells can use. This speed-up produces a couple of side effects, one being the aforementioned perception of time slowing down. More immediately noticeable is increased body temperature, which can manifest itself in the "cooling" process known as sweating. But that's not fair - weren't you told never to let them see you sweat? And because burning all that glucose is also a de-hydrative process, it can cause your mouth to go dry, especially when the facility puts out gallon jugs of water in front of every audience member but non at the podium.

Finally, whenever we send out hormones there's always an anti-hormone emitted to keep it company, and in the case of the adrenals we're talking nor-adrenaline. Nor-adrenaline's effect is to increase your blood pressure, which you typically feel in the form of flushness in the face.

So if you've ever found yourself walking into the auditorium, or perhaps the boardroom or conference area and felt your heart beating a little faster, with a discernible thump-thump, thump-thump, and your brain both a little less sharp than it should be and stuck in a minor time warp; if you've ever felt moistness in your palms or around the collar and your face a bit flushed, then congratulations! Your body is performing precisely to spec!

What you need to take home here is the understanding that, no matter what you may be consciously thinking, your sympathetic nervous system will always respond to external stimuli in the way it is hard-wired to do so. Every time. That is why so much advice on overcoming fears is worthless - no amount of "positive thinking" or alternate perceived realities such as NLP ?therapy? will cause your body to respond to an outside threat differently.

As long as you expose yourself to certain stimuli, your body's response will be the same. It is why our species has survived this long. Sounds depressing, huh?

Well, the good news is that although you cannot change your response to certain stimuli, you certainly can change the type and frequency of the stimuli to which you expose yourself. More on this in a future column.