High blood pressure riskier if it fluctuates, doctor warns
Hypertension patients whose blood pressure fluctuated had to watch out even more than those whose blood pressure was always high, cardiologist Jennifer Kwok Miu-fong said yesterday at a function to promote walking among blood pressure patients.
She cited a recent study that found people with high blood pressure that fluctuates are more likely to suffer from stroke than those whose blood pressure is high but stable.
The British research, published in the Lancet, studied 1,012 patients with hypertension. It found that 2.7 per cent of those who had stable high blood pressure developed strokes, far fewer than the 4 per cent of those who had fluctuating systolic pressure.
Systolic pressure is the peak pressure in the arteries that occurs when the heart muscles contract to push blood out to the rest of the body. It is considered to fluctuate if it varies between a level lower than 140 millimetres of mercury (the level above which a person has high blood pressure) and one higher than 180mmHg.
A person is also considered to have hypertension (high blood pressure) if the diastolic pressure - the minimum pressure in the arteries, which occurs when the heart's chambers are relaxed and filled with blood that has returned from the rest of the body - exceeds 90mmHg.
Kwok urged hypertension patients to exercise regularly, citing another British study, which proved walking was beneficial to one's health.
The 2007 study, which covered 106 office workers over a span of 12 weeks, showed that three brisk 30-minute walks a week could lower the systolic blood pressure by 5mmHg and reduce the circumference of the waist and hip by 2.6cm and 2.4cm, respectively.
Researchers said the effect was the same if participants chose to walk in bouts of at least 10 minutes.
A 2008 government survey showed that 9.3 per cent of Hongkongers, or about 617,000 people, had hypertension. While 0.7 per cent of people younger than 44 had high blood pressure, 41.6 per cent of those 65 or over had the condition.
A Department of Health survey in 2005 showed 30 per cent of patients at private clinics did not know they had hypertension. The condition kills about 11,000 people a year.