Hypertension is the term for blood pressure that remains elevated for prolonged periods of time.
Blood pressure in the elderly can be higher and still be considered normal. 80 mm Hg is an average diastolic or resting pressure. Blood pressure is determined by a complex system of circulating hormones, many of which are made in the kidneys. The hormones control the diameter of the arteries and thereby control the pressure in the arteries. Approximately 5 percent of all cases of hypertension are due to treatable or reversible causes, including some hormone imbalances or kidney problems.