You actually need a moderate level of anxiety to perform optimally. Without anxiety, you do not have arousal nor energy, and hence you don't perform well. On the other hand, if you have severe anxiety such as seen in an anxiety attack, then you also do not perform well. This relationship between anxiety and performance can be graphed and mapped out, and when it is plotted on a graph, it looks like an inverted-U. For more details on using moderate levels of anxiety to perform optimally, please click here.
