What characterizes a person with hyperthyroidism according to the text?

A person with hyperthyroidism is characterized by a ramped up metabolism. This condition occurs when the thyroid gland produces too much thyroid hormone, which accelerates the body's metabolic processes. As a result, individuals often experience a variety of symptoms related to increased metabolism, such as weight loss despite an increased appetite, excessive sweating, and nervousness or irritability.

The heightened metabolic state can also lead to a rapid or irregular heartbeat and increased sensitivity to heat, distinguishing hyperthyroidism from other conditions that might feature low energy levels or weight gain. These other signs point towards a different condition, such as hypothyroidism, where metabolism is slowed down, leading to fatigue, weight gain, and cold intolerance. In the case of hyperthyroidism, the body's heightened energy usage makes individuals feel more active and contributes to the increased energy metabolism observed.