Identify a common sign of hyperglycemia.

Frequent urination and excessive thirst are hallmark signs of hyperglycemia, which occurs when there is an elevated level of glucose in the bloodstream. This condition can lead to a state known as osmotic diuresis, where high glucose levels in the blood cause the kidneys to excrete excess glucose through urine. As the glucose is excreted, it pulls water along with it, resulting in increased urination. The body, in response to fluid loss, triggers sensations of thirst to encourage fluid intake and restore hydration. This combination of polyuria (frequent urination) and polydipsia (excessive thirst) is a classic indicator of hyperglycemia.

Other signs, although they may also be present in hyperglycemic individuals, are not as directly indicative. For example, nausea can occur due to various reasons, including metabolic disturbances, but it is not a primary sign of high blood sugar. Dry skin could indicate dehydration resulting from fluid loss, but it is less specific and not typically used as a primary indicator of hyperglycemia. An elevated heart rate might occur in various conditions, including stress or dehydration, and doesn't specifically signal hyperglycemia either. Thus, frequent urination and excessive thirst stand out as the most relevant and