At least 13 million Thais have suffered from hypertension for years with many not realising they had the condition, a health authority says.
Less than half of people diagnosed with the condition realised they had the problem for a long time before the doctor's diagnosis, the Disease Control Department warned Sunday.
Hypertension -- more commonly known as high blood pressure -- contributes to a four-times higher risk of brain blood-vessel diseases and twice the risk of heart muscle paralysis, said department director-general Jedsada Chokdamrongsuk, citing information released by the World Health Organisation.
The prevalence of hypertension among Thais continues to rise, he said, adding the country's latest report of hypertension prevalence in 2014 shows Thailand has 25% prevalence of hypertension among Thais aged 15 and older.
At least 13 million people are found to be suffering hypertension. Among those people suffering from hypertension, only 44% were aware they had the problem.
They were left without proper treatment, which can lead to deadly complications.
Hypertension heightens the risk of heart disease, paralysis and kidney disease, which are leading causes of deaths in Thailand, he said.
In terms of health care costs, Thailand now spends about 25.2 billion baht per year on the costs of treatment for five leading non-communicable diseases -- diabetes, hypertension, heart disease, brain blood-vessel disease and cancer, he said.
Of the 25.2 billion baht, 2.4 billion baht goes to the treatment of hypertension alone, he said.
In its early stage, hypertension normally doesn't show any clear warning signs, he said.
Only when the condition has developed to a severe stage, do certain symptoms show.
They are headaches, drowsiness, palpitation (a rapid and irregular heart beat), blurry vision, fatigue, dizziness and disorientation, difficult breathing and other complications.
He said Thais should get their blood pressure measured often as it can help alert people to early onset signs of hypertension.
The ideal range is less than 120 over 80 (120/80) mmHg.