At what blood pressure levels (either too high or too low) should I be alarmed and seek a doctor's advice?
You should consult a physician for treatment of hypertension if you fit into the categories below.
When should you be alarmed? That's subjective. Physicians are alarmed when they see systolic blood pressure (SBP) is equal to or greater than 180 mm Hg, or where diastolic blood pressure (DBP) is equal to or greater than 120 mm Hg; HBP with any signs or symptoms (especially stroke symptoms, confusion, hallucinations, etc.) is an emergency. Patients should be alarmed long before physicians are - in other words, get treated before it becomes dangerous!
The Eighth Joint National Committee on Hypertension (JNC 8) analyzed large studies of hypertension from 1966 through 2009 - with some consideration of studies up to 2013 - and made recommendations for adults age 18 and older with hypertension. The outcomes considered in making these recommendations, i.e. what will happen if one fails to lower blood pressure (BP) were, among others:
- overall mortality
- cardiovascular disease (CVD)-related mortality
- chronic kidney disease (CKD)-related mortality
- myocardial infarction, heart failure, hospitalization for heart failure, stroke
- need for coronary, carotid, renal, and lower extremity revascularization (bypass, etc.)
They rated their recommendations on strength of evidence. Grades were assigned.
A: Strong - based on substantial (good) evidence (strongly recommended)
B: Moderate - the net benefit is moderate to substantial
C: Weak - moderate certainty that there is a small net benefit
D: Against -no net benefit or that risks/harms outweigh benefits.
E: Expert Opinion - insufficient evidence but the committee recommends (no great studies available) - further research recommended
N: No Recommendation for or against - insufficient/unclear/conflicting evidence; further research is recommended in this area.
Grade A: aged 60 years or older, treat to lower BP if systolic blood pressure (SBP) is equal to or greater than 150 mm Hg, or diastolic blood pressure (DBP) is equal to or greater than 90 mm Hg. Goal: SBP < 150 mm Hg; DBP < 90 mm Hg. (controversial for individuals 60 years or older who do not have diabetes or chronic kidney disease)
Grade A: ages 30 through 59 years, treat DBP of 90 mm Hg or higher; goal DBP < 90 mm Hg.
Grade B: patients < 60 years with hypertension (HTN): treat; goal: BP < 140/90 mm Hg.
Grade E: ages 18 through 29 years, treat DBP of 90 mm Hg or higher; goal DBP < 90 mm Hg.
In patients with SBP between 130-150 mm Hg, there was no increase in risk in adverse effects.
LOW BP: There are no JNC8 recommendations; the decision to treat is based on expert opinion only. Goal: decrease symptoms; treat underlying cause (if any) (I.e.: if you're active, have no problems, but your BP is 80/60 - well... that's great! No adverse outcome is known.
Please see references for other treatment groups and recommendation strength.