Thousands more people will be offered blood pressure lowering drugs as part of a drive to prevent heart attacks and strokes.
Draft guidelines published by the National Institute for Health and Care Excellence (Nice) recommend reducing the threshold at which the treatment should be offered.
Health officials said as many as 450,000 more men and 270,000 more women with high blood pressure, or hypertension, may now be eligible.
However, in practice, many of these patients could already be receiving treatment because of variation in how earlier recommendations were implemented, Nice said.
Some estimates suggest around 50% of this group could be currently be using the drugs.
Guidance from 2011 recommends blood pressure lowering drugs are offered to adults, under the age of 80, with stage one hypertension and above a 20% risk of cardiovascular disease (CVD) over the next 10 years.
The proposed recommendations instead suggest those with an estimated 10-year risk of CVD of 10% or more are offered the drugs.
A stage one diagnosis means there is no identifiable cause of raised blood pressure in the patient and may be linked to factors including obesity, salt intake, physical activity or genetics.
It is estimated around 450,000 men and 270,000 women in England would fall into this category of having stage one hypertension and a CVD risk between 10% and 20%.
Anthony Wierzbicki, chairman of the guideline committee, said: “A rigorous evaluation of new evidence has resulted in updated recommendations around when to treat raised blood pressure that have the potential to make a real difference to the lives of many thousands of people with the condition.
“The guideline effectively shifts the focus to earlier intervention with lifestyle or drug treatment because this may slow the age-related deterioration of blood pressure.
“This would keep people well for longer and reduce the long-term need for multiple medications.”
The new draft guidance supports an ambition to prevent 150,000 strokes and heart attacks over the next years, outlined in the NHS long-term plan.
Professor Jamie Waterall, national lead for cardiovascular disease prevention at Public Health England, said: “High blood pressure is the country’s leading cause of heart attacks and strokes yet millions remain undiagnosed.
“Diagnosing high blood pressure earlier and managing it in line with Nice guidance will save thousands of lives and years spent in ill-health.
“That’s why we’ve set new national ambitions to improve the detection and management of high blood pressure within the next decade.
“If you’re over 40, getting your free NHS health check is a simple way to find out your blood pressure as well as your risk of other serious conditions.”
Professor Helen Stokes-Lampard, chairwoman of the Royal College of GPs, said: “Taking steps to prevent cardiovascular disease in patients is vital to help safeguard their long-term health and wellbeing, and it is a key pledge in the NHS long-term plan.
“But many GPs do also have concerns about over-diagnosis and the unintended harms of prescribing medication to groups of patients when the benefits may be limited.
“Lowering the threshold for making a diagnosis of hypertension, or high blood pressure – a condition that already affects a very large number of patients in the UK – is likely to affect thousands, if not millions of patients, so this decision must not be taken lightly and must be evidence-based.”
A consultation on the draft guidance will close on April 23.