More than 145,000 people in South Yorkshire are ‘ticking time bombs’ unaware they have high blood pressure.
Public Health England has released the statistics as part of an ‘action plan’ to spot more cases of hypertension, which produces no symptoms, but can trigger heart attacks and strokes.
The organisation says billions of pounds are spent by the NHS on treating patients unaware they have the condition.
In Sheffield, 60,610 people are estimated to have undiagnosed high blood pressure, with a further 26,450 in Rotherham.
Meanwhile there are an estimated 24,320 undiagnosed cases in Barnsley and 33,910 in Doncaster.
Dr Zak McMurray, clinical director of the NHS Sheffield clinical commissioning group, said 13 per cent of adults in the city are known to have high blood pressure,
He said: “Estimates show a further 11 per cent may have high blood pressure, but have not yet been identified – this is about in line with England as a whole.
“More than three-quarters of those identified with hypertension in Sheffield have their blood pressure successfully controlled through changing their lifestyles and medication.
“We strongly recommend people to get their blood pressure checked and to see their GP if it is too high.”
He said most city GP surgeries offer health checks for people aged between 40 and 74, assessing their risk of heart and kidney diseases, and diabetes, which includes a blood pressure check.
Tests are also offered at many pharmacies.
Prof Peter Weissberg, medical director of the British Heart Foundation, said: “There are millions walking around with this ticking time bomb.”