What vital sign indicates a red flag if heart rate exceeds which number?

The indication that a heart rate exceeding a certain threshold represents a red flag relates to how elevated heart rates can signify potential physiological distress or underlying issues requiring further assessment. A heart rate above 120 beats per minute is often recognized as tachycardia in adults, which can be alarming and may indicate stress on the cardiovascular system, dehydration, fever, pain, or other medical conditions.

When heart rates exceed this level, especially in a clinical context, it prompts emergency responders to investigate further, taking into account other vital signs and patient history. While lower rates may still indicate concern depending on the individual and context, the threshold of 120 is commonly acknowledged in clinical guidelines as a point where further action is typically warranted. This makes it a vital sign not only to monitor but also to respond to, thereby classifying it as a "red flag" in patient assessment.