Stress can either be perceived as feeling good/positive or bad/negative depending on the context, and the body reacts differently to both kinds. However, where the body isn’t so clever is distinguishing between very serious threats (like being robbed or starved) and events that are stressful but not actually life-threatening. Unfortunately, whether a problem is very serious or not, the body usually has no way of knowing the difference− — anything that causes you to worry, anticipate, regret, overthink or panic can send your stress levels through the roof.
The activity of neurons generate electric currents; and the synchronous action of neural ensembles in the cerebral cortex, comprising large numbers of neurons, produce macroscopic oscillations. These phenomena can be monitored and graphically documented by an electroencephalogram (EEG). The electroencephalographic representations of those oscillations are typically denoted by the term 'brainwaves' in common parlance.