Ignoring 'white-coat' pressure dangerous

11

111A blood-pressure reading contains two numbers that represent two different pressures. You may have heard blood pressures quoted as 120 over 80 or 140 over 90. The 120 number represents what is known as systolic pressure and the 80 is the diastolic pressure. Systolic pressure is the force exerted by blood pumped out of the heart to the blood vessels in the body. Diastolic pressure is the pressure in the vessels when the heart is relaxed. A normal pressure should be below 140 over 90. For those with certain medical conditions such as diabetes, a normal pressure is lower than 130 over 80. Hypertension is the number one risk factor for stroke. The complications for high blood pressure are very concerning, as it affects the eyes, kidneys and the heart.

Risk factors for high blood pressure

Your chances of developing high blood pressure increase with aging. It is estimated that 50 per cent of those over the age of 60 have high blood pressure. Obesity, kidney disease and diabetes are also risk factors. Your ethnic background can also be a factor as you are more likely to have high blood pressure if you are from South Asia, or from aboriginal or African-American ancestry. Excessive alcohol consumption, excessive caffeine consumption, sleep apnea, high stress levels and cigarette smoking are also contributors.

The white-coat phenomenon

This phrase applies to blood pressure that is only elevated when you are at a medical visit, whether at your physician's office or the emergency department or walk-in clinic. It means that if you are feeling anxious at these visits, your blood pressure may be high but throughout the rest of your day, your blood pressure is normal. Approximately 20-30 per cent of patients with high blood-pressure readings will have this falsely high blood pressure (white-coat hypertension). Unfortunately, too many people with possible white-coat hypertension tend not to return to see their physician to have their blood pressure monitored. Anyone with a borderline blood pressure or white-coat hypertension should follow up with their family physician as soon as possible. Over 50 per cent of those with a high normal blood pressure reading go on to develop hypertension within four years.

How a diagnosis is made

High blood pressure diagnosis guidelines have become more aggressive in the last five years. The Canadian Hypertension Society (now part of Hypertension Canada) recommends that physicians make a diagnosis within one month of the initial blood-pressure reading by using more than one blood-pressure reading. Very high blood pressure should be treated even at the initial visit. Your physician may also order some other tests related to complications of high blood pressure. When there is doubt as to whether someone may truly have high blood pressure, a 24-hour blood-pressure monitoring can be done. This is a take-home blood-pressure device that you wear for 24 hours and it automatically takes your blood pressure at certain times. Do not rely on blood-pressure machines in stores to tell you if your blood pressure is OK. Your blood pressure should always be monitored by a medical or nursing professional.

Treatment

Research has shown that even those with borderline high blood pressure need to be treated because there is still a higher-than-average risk for stroke and heart disease. Usually, medication intervention is required to treat hypertension, but exercise is also important in the lowering of blood pressure. Weight reduction should also be a key focus. Also, keeping the amount of salt in your diet to a minimum is wise. Adults need only 1500 mg or less of salt per day and if you are over age 50, 1200 mg per day is plenty. Reduction of blood pressure will lower your risk of stroke by 40 per cent and risk of a heart attack by 25 per cent. If you have been told that you have white-coat hypertension, treat it like it may be true high blood pressure. Go back to your physician and have your blood pressure followed. For more information, check out the "For General Public" section on the Hypertension Canada website, www.hypertension.ca

Readers can ask Dr. Kennedy questions, but due to the volume of requests, replies are not guaranteed. Email

askthedoctor@freepress.mb.ca

Republished from the Winnipeg Free Press print edition September 7, 2010 D1