What common sign is indicative of hypothyroidism?

Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormones. One of the significant signs of hypothyroidism is cold intolerance. This occurs because thyroid hormones play a crucial role in regulating metabolism and energy expenditure. When there is a deficiency of these hormones, the body's metabolic processes slow down, leading to a decreased ability to generate heat. As a result, individuals with hypothyroidism often feel colder than those with normal thyroid function.

In contrast, the other options represent conditions typically associated with hyperthyroidism or different metabolic states rather than hypothyroidism. For example, increased appetite and weight loss are signs of hyperthyroidism, where the body's metabolism is ramped up, leading to increased energy expenditure and, consequently, a greater appetite despite weight loss. An increased metabolic rate is characteristic of hyperthyroidism as well, further distinguishing it from the metabolic slowdown experienced in hypothyroidism. Understanding these differences in symptoms is key to accurately identifying and managing thyroid conditions.