Adrenaline and your body

Have you ever thought of adrenaline could be a bad thing?
When i mention adrenaline the first thing to come to mind is flight and fight response but it's more than that it is involved in some little functions of the body. It is secreted by the adrenal medulla and also released by the sympathetic postganglionlionic nerve endings.
It helps to regulate blood pressure by acting through heart and blood vessels. Adrenaline increases systolic( contraction) pressure by increasing the force of contraction of the heart and cardiac output. The diastolic(relaxation) pressure is decreased by reducing the total peripheral resistance.
The constriction and dilation of blood vessels is achieved through some receptors in some areas of the body like skeletal muscle, liver and heart. The constriction is by alpha receptors and dilation is by beta-2 receptors. The total peripheral resistance is reduced as a result therefore leading to decrease in diastolic pressure.
We know apnea is the temporary arrest of breathing but there is a term called adrenaline apnea which is the apnea that occurs after the injection of adrenaline. When someone is injected with adrenaline it causes a marked increase in arterial blood pressure and it also stimulates baroreceptors which in turn reflexly inhibit vasomotor center and respiratory centers causing fall in blood pressure and apnea.
At the beginning i said adrenaline could be a bad thing despite all it's usefulness. Imagine a boy that barely talks to people and doesn't like to talk much is asked to address a crowd, his heart starts to race adrenaline is pumped and his senses are heightened and so on at that point he flop if he does not control himself well so also will a man that wants to face a panel of judges when he is about to be judged.
At this point you don't like adrenaline so much because all you will do is stammer all through the presentation and this is bad. The good news is you can perform better if u can learn to suppress the adrenaline. Some of the following are things you can do;
Do some relaxation exercises: if you are able to relax it would be easier to communicate with people under stress. You can do things like taking a deep breath(this will stop acute adrenaline shock by lowering you blood pressure and lowering your heart rate), paying close attention to what is around you and appreciate them this will ease pressure from you, slowly relax and tense your muscles as this will help you to focus on physical sensations and puts your mind away from what is actually bothering you.