Understanding Your Blood Pressure Readings

High blood pressure (hypertension) is one of the most common long-term health conditions in Canada, and many people who have it do not know. It rarely causes symptoms, so regular checks are the only reliable way to find out.

What the two numbers mean

A blood pressure reading is written as two numbers, for example 118/76 mmHg.

• The top number is the systolic pressure, the pressure in your arteries when your heart beats
• The bottom number is the diastolic pressure, the pressure when your heart relaxes between beats

Both numbers matter. A raised value in either one increases the risk of heart attack, stroke, kidney disease and dementia over time.

Home readings versus clinic readings

Hypertension Canada encourages home blood pressure monitoring because it gives a truer picture than an occasional reading at a clinic. Some people's pressure rises when they are with a health care provider (sometimes called white-coat hypertension), while others have normal clinic readings but high readings at home (masked hypertension).

Because home readings are taken in a relaxed setting, the cut-off is lower than many people expect. Under Hypertension Canada guidance, a home average of 135/85 mmHg or higher is considered high. Readings taken in a clinic or pharmacy are usually judged against a higher threshold, and your provider will interpret them together with your home results.

Your personal target may be lower if you have diabetes, kidney disease or heart disease. Ask your provider what your goal is.

Choose a validated monitor

Not every monitor sold online is accurate. Look for an automatic upper-arm monitor that has been independently tested.

• Hypertension Canada lists recommended devices on its website, and many packages display a Hypertension Canada recommended logo
• Choose an upper-arm cuff over a wrist monitor unless your provider advises otherwise
• Measure your upper arm and pick the right cuff size, as a cuff that is too small gives falsely high readings
• Bring your monitor to a pharmacy visit so a pharmacist can compare it with a reference reading

How to measure correctly

Small details make a big difference.

• Avoid caffeine, smoking, cannabis and exercise for 30 minutes before measuring
• Empty your bladder and sit quietly for five minutes
• Sit with your back supported, feet flat on the floor and legs uncrossed
• Rest your bare arm on a table so the cuff is at heart level
• Do not talk or look at your phone during the measurement
• Take two readings one minute apart and record both

A simple home monitoring routine

Hypertension Canada describes a standard approach that many providers use:

• Measure twice in the morning, before medicines and breakfast
• Measure twice in the evening, before dinner
• Do this for seven days in a row
• Ignore the first day, then average all the remaining readings

Bring the log or your monitor's app to your appointment. Many modern monitors calculate averages for you.

Very high readings

If your reading is 180/110 or higher, sit quietly for a few minutes and measure again. If it stays that high, contact a health care provider the same day. Call 911 right away if a high reading comes with chest pain, shortness of breath, sudden weakness or numbness, trouble speaking, confusion, a severe headache or changes in vision.

Low blood pressure

Readings below about 90/60 may be low. This is not always a problem, but if you feel dizzy, light-headed or faint, especially after starting a new medicine or when standing up, speak to your pharmacist or doctor.

Everyday habits that help

Lifestyle changes can lower blood pressure and help medicines work better.

• Cut back on sodium by limiting processed meats, canned soups, frozen dinners, salty snacks and restaurant meals, and check the % Daily Value on food labels
• Eat plenty of vegetables, fruits, whole grains, legumes and low-fat dairy
• Be active most days of the week
• Keep alcohol low, in line with Canada's Guidance on Alcohol and Health
• Stop smoking or vaping, and ask your pharmacist about cessation aids
• Aim for seven to nine hours of sleep and get checked if you snore loudly or stop breathing at night

About your medicines

Many people need one or more medicines to reach their target. Take them every day, even when you feel well, because blood pressure medicine works only while you are taking it. Some cold remedies with decongestants and some anti-inflammatory pain relievers can raise blood pressure, so check with a pharmacist before buying over-the-counter products.

Our pharmacists are available around the clock to answer questions about your readings, your monitor or your medicines.