Which symptom could indicate high blood sugar levels in diabetics?

Dry mouth is a symptom that can indicate high blood sugar levels in individuals with diabetes. When blood sugar levels rise, it often leads to increased urination as the body attempts to rid itself of excess glucose. This process can result in dehydration, and subsequently, a dry mouth. This symptom is part of a cluster of signs and symptoms associated with hyperglycemia, including excessive thirst and frequent urination.

In contrast, increased energy is typically associated with stable blood sugar levels or possibly low blood sugar due to a surge in adrenaline and cortisol. Improved vision usually occurs when blood sugar levels are well-controlled, not when they're high. Weight gain can be related to a variety of factors in diabetes management, but it is not a direct indicator of high blood sugar levels alone.