What is LDL Cholesterol?

LDL particles do not always pass an artery wall and move on. Some are retained inside the wall, and the cholesterol they carry stays behind with them. Repeated over years, that retention is what builds the deposits that narrow an artery.

The usual calculation subtracts HDL Cholesterol and a triglyceride-based estimate from Total Cholesterol. ApoB is not part of the calculation: it counts LDL and related particles rather than the cholesterol inside them. Reading ApoB and LDL Cholesterol together therefore separates how many particles are circulating from how much cholesterol they hold.

Saturated fat changes how much cholesterol the liver packages into these particles, and inherited differences in the receptors that pull the particles back out of the blood set how fast they are cleared. Carrying excess body fat raises the number of these particles the liver puts out, and physical activity shifts both that number and the cholesterol inside each, across months rather than weeks.

LDL Cholesterol shifts over weeks with diet and body weight, and over months as the rate at which particles are cleared changes. The retention inside the artery wall accumulates over years, and yearly measurement is spaced to that process rather than to the few weeks of eating before any one test. This is Do Health's monitoring schedule, not a general recommendation for everyone.