Blood pressure is reported as two numbers and most people know neither what they measure nor what theirs should be.
The two numbers
The first, systolic, is the pressure when the heart contracts. The second, diastolic, is the pressure between beats when the heart is filling.
Both matter. Elevated systolic pressure is the stronger predictor of risk in older adults; both are relevant in younger ones.
The ranges
Definitions vary slightly between guidelines. Broadly, around 120 over 80 is considered normal, with progressively higher categories above that, and treatment thresholds depending on other risk factors.
The exact category matters less than the trend over time and what a doctor makes of it in context.
Why it is called silent
High blood pressure produces no symptoms for years while damaging arteries, kidneys, eyes and heart. By the time something is felt, damage has occurred.
That is the entire reason for screening a symptom-free population, and it is why the condition is worth taking seriously despite feeling like nothing.
Measuring it properly
Seated, feet flat, arm supported at heart level, after a few minutes of rest, without talking. Readings taken while rushed or immediately after arriving are consistently higher.
Multiple readings over days are far more informative than one, which is why home monitoring is often recommended.
What affects it
Salt intake, weight, alcohol, physical activity, sleep, and stress all have measurable effects. So does genetics, which is why some people with excellent habits still need medication.
The necessary caveat
This is an explanation of what the numbers mean. What to do about yours is a conversation with a doctor.