What is considered an abnormal vital sign regarding heart rate?

An abnormal vital sign regarding heart rate is identified as being below 60 beats per minute (bradycardia) or above 100 beats per minute (tachycardia). A normal resting heart rate for adults typically falls between 60 and 100 beats per minute. Deviations from this range can indicate underlying health issues. Heart rates below 60 may be normal for some individuals, such as athletes, but in general, for most adults, it signals a potential concern that may require further assessment. Conversely, a heart rate over 100 can indicate stress, stimulant use, or various medical conditions. Therefore, either of these extremes is considered abnormal.

The other options reflect heart rates that fall within the normal physiological range or are specifically mentioned as exact or narrow parameters, which do not suggest any abnormality. For instance, a heart rate of exactly 80 beats per minute is normal, as is a heart rate between 70 and 90 beats per minute.