Normal blood pressure not good enough

Young adults whose blood pressure is at the high end of the normal range might want to start watching what they eat, exercise and even take medication.

For they could find themselves with damaged heart muscles by middle age and full-blown heart failure some years down the road.

A new American study has found that even though people with blood pressure of below 140/90 were not considered to have hypertension, or high blood pressure, this was still enough to affect their hearts.

The study of 2,479 young adults over a 25-year period was published this week in the Journal Of The American College Of Cardiology.

The top number, or systolic pressure, measures the force from the heart as it contracts; the bottom diastolic number measures the pressure in the arteries when the heart relaxes between contractions. Desired blood pressure is less than 130/80 and a person with a reading that tops 140/90 is considered to have hypertension.

The study found that those with high diastolic readings were 70 per cent more likely than those with the lowest reading to get a treatment-resistant form of heart failure where the heart muscle is unable to relax.

"A number of patients in our study had high-normal blood pressure in their 20s and 30s, but by the time they were 45, they had the heart function of a 75-year-old," said Professor Joao Lima of Johns Hopkins University School of Medicine, the study's principal investigator.

The study suggested that "long-term blood pressure control in early young adulthood may be important to prevent coronary heart disease".

Cardiologists in Singapore were not surprised by the findings, saying that hypertension is a known major risk factor for heart problems.

They said it was expected that damage to the heart increases as blood pressure goes up.

Associate Professor Poh Kian Keong, a senior cardiologist at the National University Heart Centre, Singapore, said the study "alerts people to consider medical therapy and lifestyle changes such as taking less salt" if their blood pressure is borderline normal.

He said he has several young patients with borderline normal blood pressure, usually caused by genetic factors. Prof Poh said he would put these patients on medication because the study suggests that "if you don't treat them, they will be worse off in the long run".

The lead author of the study, Dr Satoru Kishi, a cardiologist at Mitsui Memorial Hospital in Tokyo, said the current "high normal" blood pressure may be too high and far from normal for some people.

However, Dr David Sim, director of the heart failure programme at the National Heart Centre Singapore, said while hypertension is a known risk factor for heart failure in elderly patients, there is less knowledge about its effect on younger patients.

"We won't know whether the results from that study will apply to Singapore until a similar study is replicated here," he said.

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This article was first published on June 26, 2015.
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