The word alert is used to denote to a state when one is being watchful for any possible danger, or a situation that one anticipates to occur. The state of alertness is often induced in people by external agencies by warning them against danger that might occur if they are casual. For example a person might be warned to not use any implosive while in an area which is prone to catching fire. Thus, spreading of awareness often lead to the alertness among people and often aids in averting of the accidents. The state of alertness can be understood by studying brain waves through EEG. EEG shows that when a person is alert, beta wave or gamma waves are predominant. Apart from this, alertness is caused by predominant physiological arousal, caused by the activation of the sympathetic nervous system. When a person perceives that situation around them do not requires being alert, reappraisal occurs which leads to the restoration of homeostasis in the body.