Confusion oftentimes exists among individuals outside the medical community over the question of what is a normal blood pressure (BP). This confusion stems from the fact that normal blood pressure applies only to individuals who do not have high blood pressure (hypertension) or certain other health conditions. A target blood pressure on the other hand, is one which physicians set as a goal when treating patients with hypertension.
Normal BP is a reading less than 120/80. The lower limit of normal is generally the pressure at which lightheadedness or fainting might occur. It varies between individuals, but 90/60 is the generally recognized number for most healthy people. Therefore, the normal blood pressure range is generally between 90/60 and 119/79. Pre-hypertension is a range between the upper limit of normal and the lower limit of hypertension. It is defined by readings between 120/80 and 139/89. Hypertension is a BP reading of 140/90 or greater.
A target blood pressure is a lowered reading which a doctor attempts to achieve when treating a patient with hypertension. The target varies depending upon the patient’s age and other health conditions. The cut off point for age is 60 years. The other health conditions are chronic kidney disease and diabetes.
Experts in the medical field establish the blood pressure targets. In years past, the experts primarily relied upon their opinions based on experiences. In recent years they have depended more upon information obtained from clinical research. They review the literature on the topic and select what they consider to be the best research on which to base their recommendations. That approach of using the best information from clinical research to make treatment recommendations and decisions is evidence-based medicine. Since being introduced into the medical field in 1992, it has become increasingly popular and is now used to set the standard for treatment of many diseases and conditions.
The panel of experts that sets the BP targets and treatment guidelines is the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC). The appointed panel members of the 8th Joint National Committee (JNC 8) published the most recent targets and guidelines in December 2013. The BP targets are as follows:
- Age ≥ 60 years – <150/90
- Age <60 years – <140/90
- All ages with diabetes but no chronic kidney disease – <140/90
- All ages with chronic kidney disease but no diabetes – <140/90
There is disagreement among experts within the medical field, including some of the ones that were part of the JNC 8 regarding the appropriateness of some of the recommendations, but the consensus is that guidelines are not rules and that treating physicians’ clinical judgment should override any guidelines.
The importance of clinical judgment in establishing blood pressure targets is extremely important because no two individuals are exactly the same. Depending upon one’s medical state an acceptable BP level for one patient might be too low for another. That is particularly true in individuals 60 years of age or greater who may have reduced blood flow to the brain due to heart weakness or partial blockage of vessels supplying blood flow to the brain.
Lightheadedness and fainting are common warning signs that the BP is too low, even if it is a normal blood pressure based on the reading. An important take-home message is a normal blood pressure is not always a safe and healthy one.