Which of the following best defines the term 'hypertension'?

Hypertension is defined as increased blood pressure, which is a condition where the force of the blood against the walls of the arteries is consistently too high. This condition can occur when the blood vessels become narrow or the volume of blood increases, leading to various health complications over time if left untreated. Monitoring blood pressure is crucial because persistent hypertension can lead to serious issues such as heart disease, stroke, and kidney problems.

The other terms provided do not relate to hypertension; for example, high blood sugar levels refer to hyperglycemia, low calcium levels pertain to hypocalcemia, and a weak immune response relates to immune deficiency. Each of those terms defines a different health condition, highlighting how hypertension specifically pertains to blood pressure levels in the arterial system.