Under pressure: How to use the new blood pressure guidelines

A woman checking her blood pressure at home.
High blood pressure that is not well controlled can lead to serious health conditions.

In November 2017, the American Heart Association (AHA) and the American College of Cardiology (ACC) released new guidelines for blood pressure, lowering the range of what’s considered a high blood pressure reading. The end result: 46 percent of Americans now are considered to have high blood pressure, up from 32 percent under the old guidelines. 

It may seem scary to think about 30 million more people having high blood pressure, or hypertension, essentially overnight. But the new guidelines are a step in the right direction. They recognize our growing understanding of high blood pressure and why we shouldn’t manage it through medical treatments alone. Patients and their doctors have to have strong communication and good partnerships in order to understand and treat this dangerous condition.

We measure blood pressure in millimeters of mercury, or mmHg. You’ve probably heard blood pressure given as one number over another number, such as 120 over 80. The first number is systolic pressure, and the second number is diastolic pressure.

The new blood pressure scale is as follows:

  • Normal blood pressure: less than 120 mmHg systolic; less than 80 mmHg diastolic
  • Elevated blood pressure: 120 to 129 mmHg systolic; less than 80 mmHg diastolic
  • Stage 1 high blood pressure: 130 to 139 mmHg systolic; 80 to 89 mmHg diastolic
  • Stage 2 high blood pressure: 140 or above mmHg systolic; 90 or above mmHg diastolic

It’s important to note that these aren’t magic cutoff points. The risk doesn’t suddenly appear once a patient crosses the threshold into a high-blood-pressure stage. It’s something patients and doctors need to be thinking about and managing long-term.

Heart and vascular risk from high blood pressure

Studies have observed that cardiovascular risk increases as blood pressure rises beginning even at 115 mmHg systolic and 75 mmHg diastolic – measurements that fall well within the range of what’s classified as normal blood pressure.

High blood pressure has a strong connection to a person’s overall risk for heart and vascular problems, including heart attacks and strokes. If you’re between ages 40 and 89, the AHA notes that your risk for heart disease and stroke doubles with every 20 points of systolic pressure and every 10 points of diastolic pressure.

Taken together with any other factors you might have, such as a family history of heart or vascular disease, or being overweight or obese, your blood pressure is a piece of the puzzle your doctor puts together to decide how to manage that risk. If you’re at relatively low risk, you might be able to lower your high blood pressure through lifestyle changes without the use of medications. If you’re at high risk, however, you’ll very likely need to use both lifestyle changes and medications. People who have high blood pressure along with another risk factor, such as diabetes or chronic kidney disease, are examples of those who are at higher risk.

Blood pressure in older adults 

The new blood pressure guidelines apply for most U.S. adults. Previous studies have recommended higher target numbers for older adults, who are at particular risk for high blood pressure. However, with people living longer and enjoying a better quality of life, the new guidelines focus more on overall risk. There are a couple of caveats to consider:

  • Even in healthy older adults, it’s important to capture standing blood pressure. That’s exactly what it sounds like: blood pressure that’s taken while you’re standing. A word of caution to seniors, however – older people are more likely to fall and are more at risk when they do, and standing up sometimes can cause a rapid drop in blood pressure because of poor blood flow to the brain. If the blood pressure drops too low, it can cause fainting, also known as syncope.
  • These guidelines don’t necessarily apply to older patients who live in nursing homes or who otherwise don’t live independently. This demographic was not studied in the SPRINT (Systolic Blood Pressure Intervention Trial) study, whose data helped inform the AHA and ACC’s new blood pressure guidelines. It’s important to talk to your loved one’s doctor about good blood pressure management. We hope to learn more about high blood pressure management in older adults in the future, as UT Southwestern is a participating site for a clinical trial examining whether intensive blood pressure control can prevent mental decline in patients with high blood pressure.

Measuring and controlling blood pressure

The AHA and ACC are clear in the new guidelines that nondrug treatments should take center stage in managing high blood pressure. That’s a responsibility for both patients and their doctors. Monitoring blood pressure should be a routine part of both doctors’ visits and everyday life for people.

We doctors need to do a better job of starting these conversations earlier, especially with the thresholds of high blood pressure starting at lower levels. Likewise, I encourage patients to check their numbers outside the doctor’s office. At-home measurements can provide more accurate information that reflects a patient’s normal routine. I recommend measuring at least three times in one sitting and averaging the results of the second and third test, because the first one tends to be too high. Keep track of these readings, and show them to your doctor. The AHA recommends blood pressure cuffs used on the biceps, or upper arm, rather than on the wrist for better readings. Your doctor can show you how to use the device.

Related reading: Should people check their blood pressure at home?

Knowing your numbers is important, but equally important is keeping them under control. If your doctor prescribes medication to lower your high blood pressure, it’s essential that you use it along with making changes in your lifestyle. Blood pressure medications aren’t as effective if you simply take them with no other changes. If your blood pressure falls within the guidelines for stage 2 high blood pressure, your doctor might prescribe two or more medications. This makes it easier to control your high blood pressure with a lower risk of side effects, rather than simply increasing the dosage of a single blood pressure medication.

One of the most effective lifestyle changes I recommend is managing how much sodium, or salt, you consume per day. As the U.S. Department of Health and Human Services notes, the average U.S. woman consumes 2,980 milligrams of sodium each day, and the average man has 4,240 milligrams. People with high blood pressure should have less than 1,500 milligrams of sodium per day, which is equal to approximately 3,800 milligrams of salt.

Many foods people think are healthy and safe, such as sandwich bread, canned vegetables, and rotisserie chicken, can be loaded with high levels of sodium. One of the easiest ways to find out how much sodium is in your food is to use smartphone apps. Several apps provide detailed nutrition information simply by searching for the brand name and the type of food – even restaurant dishes.

Related reading: Should you eat less sodium? The answer is – it depends

Although most people with high blood pressure should consume less than 1,500 milligrams of sodium per day, those who are prone to have a large drop in blood pressure while standing may not be able to tolerate a low-sodium diet. They may be more prone to have dizziness or fainting with prolonged standing. The new blood pressure guidelines aren’t going to solve the problem of high blood pressure overnight. That’s not what they’re designed to do. But I’m hopeful that they’ll start prompting more and better conversations between patients and their doctors earlier in the process, which I hope leaves people with real, practical guidance on how to keep their blood pressure under control. The more we can work together, the better we can handle this national issue.
 

Request an appointment with one of our cardiologists if you need help getting your blood pressure under control.

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