To diagnose prehypertension, you'll have a blood pressure test. Your doctor or a specialist will usually place an inflatable arm cuff around your arm and measure your blood pressure using a pressure-measuring gauge.
A blood pressure reading, given in millimeters of mercury (mm Hg), has two numbers. The first, or upper, number measures the pressure in your arteries when your heart beats (systolic pressure). The second, or lower, number measures the pressure in your arteries between beats (diastolic pressure).
Your blood pressure is considered normal if it's below 120/80 mm Hg. Other blood pressure measurements are categorized as:
- Prehypertension. Prehypertension is a systolic pressure ranging from 120 to 139 mm Hg or a diastolic pressure ranging from 80 to 89 mm Hg.
- Stage 1 hypertension. Stage 1 hypertension is a systolic pressure ranging from 140 to 159 mm Hg or a diastolic pressure ranging from 90 to 99 mm Hg.
- Stage 2 hypertension. More severe hypertension, stage 2 hypertension is a systolic pressure of 160 mm Hg or higher or a diastolic pressure of 100 mm Hg or higher.
Because blood pressure tends to fluctuate, a diagnosis of prehypertension is based on the average of two or more blood pressure readings taken on separate occasions in a consistent manner. Your blood pressure generally should be measured in both arms to determine if there is a difference. Your doctor may ask you to record your blood pressure at home and at work to provide additional information.
Your doctor may suggest a 24-hour blood pressure monitoring test called ambulatory blood pressure monitoring. The device used for this test measures your blood pressure at regular intervals over a 24-hour period and provides a more accurate picture of blood pressure changes over an average day and night. However, these devices aren't available in all medical centers, and they're rarely reimbursed.
If you have prehypertension accompanied by diabetes, kidney disease or cardiovascular disease, your doctor may recommend blood pressure medication in addition to lifestyle changes.
The benefits of medication for other adults with prehypertension are less clear. Your doctor will likely suggest that you control prehypertension with lifestyle changes, such as:
- Maintaining a healthy weight or losing weight if you're overweight or obese
- Eating a healthy, low-salt diet
- Exercising regularly
- Limiting the amount of alcohol you drink
- Quitting smoking
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Lifestyle and home remedies
As your blood pressure increases, so does your risk of cardiovascular disease. That's why it's so important to control prehypertension. The key is a commitment to healthy lifestyle changes.
- Eat healthy foods. Eat a healthy diet. Try the Dietary Approaches to Stop Hypertension (DASH) diet. Choose fruits, vegetables, whole grains, poultry, fish and low-fat dairy foods. Get plenty of potassium, which can help lower blood pressure. Eat less saturated fat and trans fat.
- Maintain a healthy weight. Keeping a healthy weight, or losing weight if you're overweight or obese, can help you control your blood pressure and lower your risk of related health problems. If you're overweight, losing even 5 pounds (2.3 kilograms) can lower your blood pressure.
Use less salt. The Dietary Guidelines for Americans recommend limiting sodium to less than 2,300 mg a day. A lower sodium level — 1,500 milligrams (mg) a day — is appropriate for people 51 years of age or older, and individuals of any age who are black or who have hypertension, diabetes or chronic kidney disease.
While you can reduce the amount of salt you eat by putting down the saltshaker, you usually should also pay attention to the amount of salt that's in the processed foods you eat, such as canned soups or frozen dinners.
Increase physical activity. Regular physical activity can help lower your blood pressure, manage stress, reduce your risk of other health problems and keep your weight under control.
For most healthy adults, the Department of Health and Human Services recommends that you get at least 150 minutes a week of moderate aerobic activity or 75 minutes a week of vigorous aerobic activity, or a combination or moderate and vigorous activity. Aim to do muscle-strengthening exercises at least two days a week.
- Limit alcohol. If you choose to drink alcohol, do so in moderation. For healthy adults, that means up to one drink a day for women of all ages and men older than age 65, and up to two drinks a day for men age 65 and younger. One drink equals 12 ounces of beer, 5 ounces of wine or 1.5 ounces of 80-proof liquor.
- Don't smoke. Tobacco injures blood vessel walls and speeds up the process of hardening of the arteries. If you smoke, ask your doctor to help you quit.
- Manage stress. Reduce stress as much as possible. Practice healthy coping techniques, such as muscle relaxation, deep breathing or meditation. Getting regular physical activity and plenty of sleep can help, too.
Preparing for your appointment
If you think you may have prehypertension or high blood pressure, make an appointment with your family doctor or health care provider to have your blood pressure checked.
No special preparations are necessary to have your blood pressure checked. You might want to wear a short-sleeved shirt to your appointment so that the blood pressure cuff can fit around your arm properly. You might want to avoid caffeinated food and drinks right before your test. You may want to use the toilet before having your blood pressure measured.
Because some medications — such as over-the-counter cold medicines, pain medications, antidepressants, birth control pills and others — can raise your blood pressure, it might be a good idea to bring a list of medications and supplements you take to your doctor's appointment. Don't stop taking any prescription medications that you think may affect your blood pressure without your doctor's advice.
Because appointments can be brief, and because there's often a lot to discuss, it's a good idea to be well-prepared for your appointment. Here's some information to help you get ready for your appointment, and what to expect from your doctor.
What you can do
- Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment. Prehypertension rarely has symptoms, but it's a risk factor for heart disease. Let your doctor know if you have any symptoms such as chest pain or shortness of breath.
- Write down key personal information, including a family history of high blood pressure, high cholesterol, heart disease, stroke or diabetes, and any major stresses or recent life changes.
- Make a list of all medications, vitamins or supplements that you're taking.
- Take a family member or friend along, if possible. Sometimes it can be difficult to remember all of the information provided to you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
- Be prepared to discuss your diet and exercise habits. If you don't already follow a diet or exercise routine, be ready to talk to your doctor about any challenges you might face in getting started.
- Write down questions to ask your doctor.
Your time with your doctor is limited, so preparing a list of questions ahead of time will help you make the most of your time together. List your questions from most important to least important in case time runs out. For prehypertension, some basic questions to ask your doctor include:
- What kinds of tests do I need?
- Do I need any medications?
- What foods should I eat or avoid?
- What's an appropriate level of physical activity?
- How often do I need to schedule appointments to check my blood pressure?
- Should I monitor my blood pressure at home?
- What are the alternatives to the primary approach that you're suggesting?
- I have these other health conditions. How can I best manage them together?
- Are there any restrictions that I need to follow?
- Should I see a specialist?
- Are there any brochures or other printed material that I can take home with me? What websites do you recommend visiting?
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment at any time that you don't understand something.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:
- Do you have a family history of high cholesterol, high blood pressure or heart disease?
- What are your diet and exercise habits like?
- Do you drink alcohol? How many drinks do you have in a week?
- Do you smoke?
- When did you last have your blood pressure checked? What was your blood pressure measurement then?
What you can do in the meantime
It's never too early to make healthy lifestyle changes, such as quitting smoking, eating healthy foods and becoming more physically active. These are primary lines of defense against high blood pressure and its complications, including heart attack and stroke.