What condition is characterized by an increased heart rate often indicating stress or illness?

Sinus Tachycardia is characterized by an increased heart rate that typically exceeds 100 beats per minute in an adult. This condition occurs in response to various stimuli, such as stress, fever, pain, anxiety, or hyperthyroidism, and serves as a physiological mechanism to meet the body's increased demand for oxygen and blood flow during those states.

The diagnosis is confirmed when the heart rhythm originates from the sinoatrial node, which is the natural pacemaker of the heart, maintaining a regular rhythm despite the elevated rate. Monitoring for sinus tachycardia typically includes assessing symptoms that accompany the increased heart rate and understanding potential underlying causes, such as dehydration or anemia.

In contrast, conditions like Sinus Bradycardia present with a slower heart rate, while Atrial Fibrillation and Ventricular Tachycardia indicate more serious and irregular heart rhythms that require different management approaches. Thus, Sinus Tachycardia is a clear indicator of the body's response to increased demands, making it the correct condition described in the question.