Which of these is a sign of hypoglycemia?

Excessive sweating is indeed a sign of hypoglycemia. When blood sugar levels drop too low, the body responds with various physiological changes as it tries to restore balance. One of these responses includes activating the sympathetic nervous system, which can lead to symptoms such as sweating. This is often referred to as an adrenergic response, which alerts the individual to the reduced glucose levels and prompts them to take action, such as consuming carbohydrates to raise their blood sugar.

While dry mouth and high heart rate can also be associated with hypoglycemia, they are less specific to this condition when compared to excessive sweating. Dry mouth can occur due to a variety of reasons unrelated to blood sugar levels, and a high heart rate can also result from stress, anxiety, or other medical conditions. Therefore, excessive sweating is a more direct and reliable indicator of hypoglycemia.