NORMAL & HIGH BLOOD PRESSURE:
It is difficult to define high blood pressure or hypertension.
Blood pressure varies from one healthy individual to another.For the same individual, blood pressure depends on the time of the day,season of the year, state of mental stress or physical exercise.
Professor Desmond G. Julian writes in ‘Cardiology'(third edition, 1979):
The mean pressure during sleep may be 30 to 40 mm Hg lower than it is in the waking state.Factors which transiently increase pressure include anxiety and cold.Exercise leads to a rise in both systolic and diastolic pressures. A transient doubling of pressure may occur at the climax of coitus.
In addition, the existence of ‘white coat hypertension’ makes the situation more complex.The blood pressure .However of an individual measured at a conventional clinic may be 10-15 mm Hg greater than the value measured at the relaxed atmosphere of home.
Previously,blood pressure was regarded to be abnormally high if it persistently exceeded 140/90 mm of Hg
However,American Heart Association(AHA) 2017 guidelines seek to lower the numbers involved in the definition of high blood pressure.They eliminated the previous category of pre hypertension (Systolic Blood Pressure,SBP in the range 120-129 and diastolic<80). According to them blood pressure categories are:
- Normal:BP less than 120/80
- Elevated: SBP 120-129 and DBP <80
- Stage1:SBP 130-139 or DBP 80-89.
- Stage2:SBP: at least 140 or diastolic at least 90.
- Hypertensive crisis:: SBP over 180 and/or DBP 120.
AAFP(American Academy of Family Physicians) has decided to not endorse the recent guidelines for its over dependence on SPRINT(Systolic Blood Pressure Intervention trial and also because of the possibility of over treatment. Earlier, 2016 European Guidelines on CVD prvention did not directly endorse SPRINT trial says it may be prudent toto recommend lowering SBP/DBP to values within the range 130-139/80-85
Journal of the Association of Physicians in India (JAPI) noted in 2013 that some evidence exist to indicate that the risk of Cardiovascular events in Indians is higher at relatively lower levels of blood pressure.In ‘Best Practices of Hypertension-2017’-(P.C. Manoria et al) gives the criteria for diagnosing hypertension as :
- Office B.P: Systolic >=140, diastolic:>=90
- Home B.P: Systolic>=135, diastolic>=85