Short answers, pulled from the story.
Normal resting blood pressure in an adult is approximately 120 mmHg systolic over 80 mmHg diastolic, written as 120/80 mmHg. Globally, the age-standardised average has remained near 127/79 mmHg in men and 122/77 mmHg in women since 1975.
Pulse pressure is the numerical difference between systolic and diastolic blood pressure readings, with a healthy value near 40 mmHg. A pulse pressure of 50 mmHg or more raises the risk of cardiovascular disease as well as eye and kidney complications. A 2000 meta-analysis found that each 10 mmHg increase in pulse pressure was associated with a 20% higher risk of cardiovascular mortality.
Hypertension can result from increases in cardiac output, systemic vascular resistance, blood volume, or arterial stiffness, and is influenced by factors including dietary salt intake, autonomic nervous system activity, and the renin-angiotensin system. Persistent hypertension is a major risk factor for stroke, heart attack, heart failure, arterial aneurysm, and chronic kidney failure. At severely elevated mean arterial pressures 50% or more above average, life expectancy is measured in years without treatment.
Three principal mechanisms govern blood pressure: the baroreceptor reflex, in which pressure-sensitive nerve endings in the carotid sinuses and aortic arch signal the brain stem to adjust heart rate and vascular tone; the renin-angiotensin system, through which the kidneys release renin that ultimately generates the vasoconstrictor angiotensin II; and aldosterone release from the adrenal cortex, which drives sodium and water retention to expand blood volume.
Orthostatic hypotension is a drop in blood pressure upon standing, defined as a systolic decrease greater than 20 mmHg or a diastolic decrease greater than 10 mmHg. Standing shifts approximately 500 millilitres of blood from the chest into the lower-body veins, reducing ventricular filling and stroke volume. When the autonomic nervous system fails to compensate within about a minute, brain perfusion falls and the person may feel dizzy or faint.
In adults, systolic pressure tends to rise from early adulthood through at least age 70, while diastolic pressure begins to fall around age 55. Pulse pressure rises markedly after age 40, driven by increasing arterial stiffness. When systolic pressure exceeds normal adult limits while diastolic remains in range, the condition is called isolated systolic hypertension; this age-related rise in blood pressure is not considered healthy and is not observed in some isolated unacculturated communities.