Final answer:
The term that describes a period of unreasonable elation and hyperactivity is 'mania.' It is associated with psychological conditions such as bipolar disorder and is characterized by increased energy, elevation of mood, and sometimes risky behaviors.
Step-by-step explanation:
Someone who is experiencing mania has a period of unreasonable elation and hyperactivity. Mania is a psychological condition marked by an abnormally elevated mood, energy, and activity levels. It can often be seen in disorders such as bipolar disorder, where an individual alternates between extreme highs (manic episodes) and lows (depressive episodes).
During a manic phase, a person might feel excessively happy and full of grand ideas, and may engage in impulsive, high-risk behaviors. The hypersecretion of certain hormones, like adrenaline, might contribute to these heightened states of arousal. Moreover, like the feelings described in times of elation, the physiological arousal can be powerful and even overwhelming, manifesting as increased heart rate, energy, and a feeling of being unstoppable or on a 'high.'