SINGAPORE - Almost one in three people will be classified as having high blood pressure, up from one in four, if Singapore adopts the new American Heart Association (AHA) cut-off guideline for high blood pressure, which is 130/80.

However, the vast majority of these newly diagnosed hypertensives, classified as "high blood pressure stage 1", will need only to make lifestyle changes to reduce the risk of suffering a heart attack or stroke.

Professor Tan Huay Cheem, director of the National University Heart Centre, said the AHA recommendation is based on solid evidence so "there's no reason" to reject it.

However, Prof Tan suggested that treatment for patients with stage 1 hypertension should focus on getting them to make lifestyle changes, and that treatment with medication should start only if they have other risk factors such as diabetes mellitus.

The 130/80 cut-off is for at least two readings done at home, he said. The cut-off at clinics remains 140/90 because anxiety tends to raise a person's blood pressure, he added.

Dr Chee Tek Siong, a cardiologist in private practice and a board member of the Singapore Heart Foundation, agreed that "there is no rush to start treatment" for people with blood pressure of 130/80.

Only those considered "high risk" because of other factors such as diabetes, high cholesterol level, obstructive sleep apnea, obesity, lack of exercise or kidney failure would need to go on medication, he said.

Dr Chee added that the rest would be given advice to make lifestyle changes and have their blood pressure checked after three to six months.

Dr Paul Chiam, a cardiologist at Mount Elizabeth Novena Hospital, said it is good for people to know the importance of strict blood pressure control "as we know that better BP control does lead to fewer strokes, heart and kidney disease".

Dr Daniel Yeo, a cardiologist at Gleneagles Hospital, said Canada and Australia have already adopted the stricter cut-off last year, so the AHA's move is no surprise.

The AHA estimates that among stage 1 hypertensives, only one in five may need medication to lower blood pressure.

Lifestyle changes include reducing salt intake, and eating more potassium-rich foods such as bananas, potatoes, avocado and dark leafy vegetables. Patients should also be encouraged to exercise more, consume less alchohol and stop smoking.