Do you know what your blood pressure is? You should!

All adult Canadians should know what their blood pressure numbers are-just like they should know their numbers for weight, cholesterol and blood sugar, says Dr. Albert Yeung, professor of medicine and pharmacology, University of Alberta, Edmonton. “Ask your doctor, write it down and keep it in your wallet.”

Why is it so important to know your blood pressure numbers?

Dr. Yeung says that knowing your blood pressure numbers “can be particularly important since most people with high blood pressure have no symptoms”. According to the Heart and Stroke Foundation of Canada, elevated blood pressure, also known as hypertension, is the number one correctable risk factor for stroke and a major risk factor for heart disease. What's more, hypertension is on the rise in Canadians 18-35 years of age, due in part to rising rates of obesity in children and teens.

Big health benefits are the pay-off for reducing high blood pressure. According to the Canadian Hypertension Society, lowering high blood pressure can reduce:

• Heart attacks by 25%
• Stroke by 40%
• Heart failure by 50%

Lifestyle choices to keep your blood pressure healthy

A healthy lifestyle is important for anyone with hypertension:

• Stop using products containing nicotine, such as cigarettes, cigars, pipe tobacco, chewing tobacco, snuff and nicotine-containing gum.
• Reduce your exposure to second-hand smoke.
• Limit your alcohol intake to no more than two standard drinks per day for men, and one drink for women.
• Spend time on things you enjoy doing and being with people you like being with.
• Manage the stress in your life by figuring out what situations make you feel stressed and find ways to avoid these situations.
• Maintain a healthy weight by eating healthy foods and enjoying physical activity most days of the week. If you are overweight, losing even a modest amount of weight can help to reduce your blood pressure.
• Choose foods according to the Dietary Approaches to Stop Hypertension (DASH) eating plan.

How is blood pressure measured?

Blood pressure is expressed as two numbers like a fraction and is measured in units called millimeters of mercury or mmHg. The top number measuring systolic blood pressure occurs when the heart beats (contracts). The bottom number measuring diastolic blood pressure occurs when the heart relaxes. Both numbers are important. When a person has high blood pressure, the elevated blood pressure can be seen with the systolic pressure (systolic hypertension), with the diastolic pressure (diastolic hypertension), or both.

Measuring up-what should my blood pressure be?

The most recent recommendations from the Canadian Hypertension Society state that for most people blood pressure should be 140/90 or lower. For people measuring their blood pressure at home the values should be 135/85 or lower. For people with diabetes or kidney disease, blood pressure should be 130/80 or lower.

One reading doesn't tell the whole story

While it's important to have your blood pressure checked at least once a year by a healthcare professional, a single blood pressure reading taken in the physician's office isn't usually enough to provide a true picture of your blood pressure. This is because blood pressure -a measure of the force exerted on the walls of blood vessels as the heart pumps out blood- can vary from minute to minute.

White coat hypertension

Blood pressure keeps changing depending on what you are doing. In the physician's office, for instance, your blood pressure reading may be higher than usual if you had difficulty finding parking or if you had to wait a long time to see the doctor. If blood pressure is high when recorded in the doctor's office, but repeatedly remains normal outside the doctor's office, this phenomenon is known as white coat hypertension or white coat effect.

Studies show that 15-30% of the general population may experience white coat hypertension. This elevation can occur even in those who are already taking medication for hypertension. “There is increasing evidence that what really matters in terms of your future risk of stroke and heart attack is what happens to your blood pressure outside of the physician's office,” notes Dr. Yeung who is also the director of the Hypertension-Lipid Clinic at the Royal Alexandra Hospital in Edmonton. “Any person who has hypertension ought to have a reliable home blood pressure monitor, but it needs to be used properly with guidance from a health professional.”

Monitoring your blood pressure at home-accuracy counts

Tips from the Canadian Hypertension Society to help ensure accuracy:

• Get the right monitor and the right cuff size. The Canadian Hypertension Society is one source for this information, or ask your doctor or pharmacist.
• Rest for five minutes before taking your blood pressure.
• Sit with your feet flat on the floor, your back supported and your arm resting at heart level on a table.
• Do not wear constrictive clothing (Dr. Yeung warns not to push up your sleeve to take a measurement as it can act like a tourniquet around your arm that will affect your blood pressure).
• Take an average of two or more readings at least two minutes apart.
• Don't talk, eat or watch TV while you're taking your blood pressure.
• Don't take your blood pressure for at least 30 minutes after drinking coffee or smoking.

Take your blood pressure twice a day (two readings each time) for one week to get an average blood pressure. Then, talk to your physician about the readings so you can get feedback on what to do next. As Dr. Yeung says, “Knowing your blood pressure number empowers you to take better care of yourself.”

Prepared by Kristin Jenkins in collaboration with Alberta Health Services. This article appeared originally on the Canadian Health Network Web site.