Making Sense of Blood Pressure Readings
Blood pressure is usually given to you in two numbers (like “120 over 80.”)
- The first number is your systolic blood pressure. That tells you how much pressure your heart puts on your artery walls when it beats.
- The second number is your diastolic blood pressure. It tells you how much pressure is being put on your artery walls between heartbeats.
Your blood pressure isn’t a static number—it can be affected by how hydrated you are, whether or not you’ve been physically exerting yourself, how stressed you are, and other factors. It may be different on different days. That’s why doctors will usually assess your results by averaging two or more readings across several office visits.
The American Heart Association divides the blood pressure range into five categories. Sometimes systolic and diastolic pressure results may fall under two separate categories on this chart, and if that’s the case, you should consider yourself in the higher category.
For instance, if your reading is 129 / 78 mm Hg, you should consider yourself in the Elevated category.
The blood pressure chart below shows you the categories at a glance:
Blood pressure ranges and categories
120 / 80 mm Hg or Below: Normal. In this category, you’re most likely in good cardiac health. Keep doing what you’re doing—or adopt a more balanced diet and exercise regime to maintain a normal blood pressure range.
120-129 / 80 mm Hg or Below: Elevated. This reading shows that your heart is putting just a little more pressure than normal on your arterial walls when it beats—and you’re at risk of developing high blood pressure later.
Now’s the time to think about improving your diet, taking up exercise, or taking other steps in consultation with your doctor to address this before it becomes a problem.
130-139 / 80-89 mm Hg: Hypertension Stage 1. This is the stage where you’re at added risk of heart attack or stroke. Your doctor may prescribe medications as well as healthy lifestyle changes to bring your blood pressure down to a more manageable level.
140 / 90 mm Hg or Higher: Hypertension Stage 2. At this point, your risk of stroke, heart attack, and other serious health crises intensifies. Again, your doctor may prescribe healthy lifestyle changes such as diet and exercise, as well as blood pressure-lowering medications, to bring your blood pressure down.
180 / 120 mm Hg or Higher: Hypertensive Crisis. This reading suggests an immediate crisis that requires medical attention. If you’re testing your blood pressure on your own and you’re not having other troubling symptoms, you can wait five minutes and test your blood pressure again. If the numbers haven’t come down, you may need to seek medical attention.
If you’re experiencing symptoms such as chest pain; dizziness; shortness of breath; pain in the back, jaw, or arms; difficulty speaking; or numbness or weakness, don’t test yourself again—call 911 immediately.
Which number should I be more worried about?
In reality, you should pay attention to both numbers when considering how at risk you are for heart disease and stroke.
Usually, doctors pay more attention to the first number of blood pressure readings—your systolic pressure. Our arteries tend to stiffen as we age, and plaque continues to build up—which will naturally result in this number increasing as we get older. The higher your systolic pressure, the greater the risk of cardiovascular disease and stroke.
However, recent studies have shown that increased diastolic pressure (the second number) is linked to risk of death from ischemic stroke. One study demonstrated that the risk doubles with every 10 mm Hg of increase in diastolic pressure (or every 20 mm Hg increase in systolic pressure). So you need to be concerned about both.
What does mm Hg mean?
The unit of measurement used to evaluate blood pressure is “mm Hg”—which stands for millimeters of mercury. This is the standard unit for measuring pressure in the body. Mercury is used as a touchpoint because the first accurate pressure gauges ever invented used mercury.
What should I do if my blood pressure reading is high?
This will depend on a lot of factors—including your existing state of health, how high your reading is, what other medical issues you have, and so on. Your doctor can help you develop a plan for reducing your blood pressure.
Some of the things your doctor may suggest include:
Stop smoking. If you smoke, quitting can do a lot to bring your blood pressure down and increase your life expectancy. Studies show that if you’ve already had a heart attack, quitting smoking can reduce your chances of having another one by 50%.
Exercise on a regular basis. Regular exercise has been shown to reduce blood pressure and help people avoid developing hypertension. Even about 30 minutes of exercise on a daily or almost-daily basis can have a measurable effect.
Eat healthy. Diet has a huge effect on heart health. Stick to a diet that emphasizes whole grains, vegetables and fruits, and low-fat dairy; stay away from foods heavy in cholesterol and saturated fat.
Eat less sodium. Sodium can increase blood pressure—and reducing it in your diet often means reducing your intake of processed foods and using other spices besides salt to season your food. Talk to your doctor about your sodium limits, as these can vary for different people—but a good target to aim for is about 1,500 mg of sodium per day or less.
Cut down on alcohol. Alcohol actually has a mixed effect on your blood pressure. A moderate amount of it—about one drink a day for women or two for men—can actually reduce your blood pressure slightly. But drink too much, and it can both raise your blood pressure and make blood pressure medications less effective.
Talk to your doctor about medications. Healthy lifestyle changes can do a lot to bring your blood pressure down, but in some cases they may not be enough. If that’s the case, your doctor can prescribe medications that can make your lifestyle changes more effective.
Keeping tabs on your blood pressure is a crucial part of making sure your heart and cardiovascular system stay healthy. Understand what those numbers mean, and you’re better equipped to know when there’s a problem—and start taking steps to preserve your heart heath.