Survival now is less dependent on outrunning a tiger and more on how we fit in with our co-workers and our broader community. So it makes sense that the exposure of making a public presentation would be a cause of anxiety, a close cousin to fear.
When you confront something scary, be it an audience of expectant faces or a tiger, adrenaline is released to help you perform. If the former, you won’t need it to run, but that adrenaline could give your speech the extra energy you’d like to emphasize the important things you have to say. However, overarousal of the sympathetic nervous system (which leads to the fight-or-flight response) can have negative repercussions.
When you are in an extreme fear state, it’s nearly impossible to utilize executive functions. Working memory declines, impulse control is stymied, and rational decision making is thwarted. You don’t need those functions to run from a tiger, but you do need them to make a speech! You need them to remember the important points you want to make, to stay on task, and to answer questions articulately and confidently. In fact, if you remain overly aroused or hypervigilant, an imbalance of the autonomic nervous system results. This has consequences for every cell in your body.
Your autonomic nervous system is like a seesaw with the sympathetic and parasympathetic branches on either side. Both ends will be activated based on your experiences, but it’s best to maintain a balance between the two. On the playground, when children of different weights are on either end of a seesaw, it’s not very fun. The heavier child stays on the ground while the lighter remains suspended in the air. The same is true of your state. It’s best when the two branches balance each other so your state can be relaxed, but still alert and enthusiastic. Autonomic balance improves outcomes and preserves health and quality of life.