High blood pressure, also known as hypertension, is becoming a national crisis, particularly among younger Canadians, say health authorities.
That's because obesity rates, physical inactivity and diabetes are on the rise — all known risk factors for high blood pressure.
When blood pressure is too high, it puts stress on the body's entire vascular system, forcing the heart to work harder and increasing the risk of death from a variety of causes, including heart disease and stroke.
According to the Heart and Stroke Foundation of Canada, high blood pressure rose 77 per cent among Canadians between 1994 and 2005, based on patients' own reports, which are less accurate than measurements.
And it spiked among Canadians aged 35 to 49, increasing 127 per cent during the same period.
"There are more than 250,000 young Canadians in their 20s and 30s with high blood pressure," said Stephen Samis, the Heart and Stroke Foundation of Canada's director of health policy. He made the statement in a report released in January 2010. "It's almost a doubling in 15 years."
During the same time frame, the incidence of diabetes rose 45 per cent among Canadians of all ages, and obesity grew by 18 per cent. Among those aged 35 to 49, diabetes rose 64 per cent and obesity by 20 per cent.
The new figures aren't exactly a surprise, Marco di Buono, director of research, Heart and Stroke Foundation of Canada, told CBC News. "We predicted that obesity was going to have a profound physiological effect on the health of our children. Fast forward 10 years, and we're now seeing 20- and 30 somethings who have high cholesterol, high blood pressure, multiple risk factors for heart disease."
Worse, experts believe the newly-released figures actually fail to show the scope of the problem. Because they're self-reported, a greater number of younger Canadians could actually be at risk of heart disease and stroke.
"We also know from other recent surveys that this is likely an underestimate," says Dr. Beth Abramson, a cardiologist and spokesperson for the Heart and Stroke Foundation. "When patients come into my office, they tell me they're a little slimmer and a little taller than they really are."
In February 2010, Statistics Canada reported that one in five adult Canadians have hypertension. The findings were based on automated measurements of blood pressure and self-reported use of blood pressure medication.
The prevalence of hypertension went up with age:
- Age 20 to 39: two per cent.
- Age 40 to 59: 19 per cent.
- Age 60 to 79: 53 per cent.
"Twenty years ago, we did a survey involving measured blood pressure, and at that time, only 13 per cent of people with hypertension had their blood pressure in the range we call 'controlled.' This compares with 66 per cent today," said Kathryn Wilkins, a senior analyst with Statistics Canada who led the study.
Campaigns to raise doctors' and the public's awareness about the importance of hypertension as a risk factor and greater availability of blood pressure machines could be paying off, Wilkins said.
Blood pressure defined
Blood pressure, the measure of the pressure or force of blood against the walls of arteries, is measured in two units, one written over the other. One is systolic (the top number), which represents the pressure when your heart contracts and pushes blood out (systolic). The bottom number is diastolic, the lowest pressure when the heart relaxes.
Normal blood pressure is below 120/80 mm Hg (also known as millimeters of mercury), according to the Heart and Stroke Foundation of Canada. High blood pressure means the reading is more than 140/90 mm Hg, and high normal ranges are between 130/85 mm Hg and 139/89 mm Hg. For diabetics, 130/80 mm Hg is considered high.
In people who have normal blood pressure, the artery walls are flexible and relaxed. However, people with high blood pressure have stiffer arteries that restrict the flow the blood. That causes the heart to beat harder and increases the pressure of blood leaving the heart.
The stiffer arteries are caused by the buildup of a fatty plaque in the artery walls, which accumulates over time. Gradually, the heart is forced to pump more intensively, weakening it while the arteries become less and less efficient at pumping blood.
Thus, high blood pressure is a major cause of heart disease. At the same time it can lead to a stroke, when an artery becomes blocked and ruptures in the brain.
Provinces most at risk
The January 2010 report from the Heart and Stroke Foundation predicts there will be disparities in the increase in the prevalence of high blood pressure across the country in the next decade.
Leading the way is the Yukon, with an anticipated growth in cases of high blood pressure of 130.4 per cent between 2005 and 2021; Northwest Territories, with a projected surge of 129.8 per cent and Nunavut, with an anticipated increase of 76.9 per cent.
The lowest relative increase in high blood pressure is expected in Manitoba at 30.4 per cent.
Keeping blood pressure low
Though high blood pressure is highly preventable, many Canadians simply aren't aware of the risks they face.
"We know that Canadians are not as aware as they need to be," says Abramson. "This shocking data showing the young age group, age 20 to 39, to be the new at-risk population, is a group of Canadians that we need to target. And they need to be aware that it can happen to them as well."
Blood pressure can be controlled through a variety of lifestyle modifications, such as diet and exercise, as well as medication. Maintaining a healthy body weight — a body mass index under 25 — is a first step in keeping blood pressure levels in a normal range. According to the Heart and Stroke Foundation of Canada, "even a modest reduction in weight, as little as 10 per cent, can dramatically decrease your chances of having a stroke or heart attack."
About 50 per cent of Canadians over 60 have hypertension, and almost half of those people are on medication for it, said Dr. Norm Campbell of the University of Calgary, a co-author of the Statistics Canada report.
"That drug treatment is protecting them from dying prematurely or having a heart attack or stroke," Campbell said. "But it's sad from the perspective that we could reduce the blood pressure through the amount of salt added to food or through other mechanisms that wouldn't really require drug therapy."
Eating foods high in fat and sodium and consuming more than a few alcoholic beverages a day can raise blood pressure. Health experts suggest eating a balanced diet low in saturated fat, with plenty of fresh vegetables and fruit. They also recommend regular exercise to reduce stress, a risk factor for high blood pressure.
Quitting smoking is also an effective way to maintain healthy blood pressure. That's because smoking can injure blood vessels, causing them to harden and restrict blood flow through the arteries.
And if blood pressure remains high, there are numerous medications that can lower it. Some include diuretics, or water pills, which flush excess water and sodium from the body, lowering blood pressure, according to the U.S.-based Mayo Clinic. Other drugs include Angiotensin-converting enzyme (ACE) inhibitors, Angiotensin II receptor blockers, Beta blockers, or Calcium channel blockers.