Symptomatic Differences  In Hyper & Hypothyroidism When the human body is exposed to excessive amounts of thyroid hormone the result is a disease known as hyperthyroidism (or thyrotoxicosis). Hyperthyroidism typically begins with a gradual onset of a constellation of symptoms, including increased nervousness and emotional instability associated with a fine tremor of the hands. The patient feels warm, perspires freely, and is intolerant of heat since a greater proportion of the body's energy is dissipated as heat. With a low functioning thyroid, the symptoms are almost endless. the diagnosis of hypothyroidism by symptoms is indeed fruitless.