What is defined as low blood pressure?

Low blood pressure, or hypotension, is generally defined as a blood pressure reading that is significantly lower than the normal range, which is typically around 120/80 mmHg. A reading of less than 100/60 mmHg indicates that the blood pressure is lower than what is considered optimal, and this can lead to symptoms like dizziness, fainting, or even shock in severe cases.

The choice of less than 100/60 is consistent with clinical definitions used to identify low blood pressure in patients. Blood pressure levels that are at or above the normal range—like those that fall under the other options provided—do not indicate hypotension. Thus, the definition given in the correct answer effectively aligns with medical standards for low blood pressure.