What is HDL Cholesterol?

The test reports the cholesterol sitting inside those particles, which counts what is being carried back rather than how well the carrying works. The same amount of cholesterol can sit in particles that clear tissues efficiently and in particles that do not.

LDL Cholesterol and Non-HDL Cholesterol measure the cholesterol on the delivery side. Triglycerides tend to move the other way from HDL Cholesterol, and one condition pushes both: when tissues respond poorly to insulin, triglycerides rise and HDL Cholesterol falls.

Physical activity and body weight change how fast HDL particles are made and cleared; alcohol intake and smoking shift how many are in circulation. Much of the difference between one person and the next is inherited. Poor insulin response loads the particles with triglyceride in place of cholesterol and reduces how many there are, and the cholesterol figure shows neither change directly.

HDL Cholesterol responds to activity, body weight and alcohol intake over weeks to months, so each measurement stands for the stretch before it rather than for that morning. Readings about every four months divide the year into three such stretches, and a change between them has had to last weeks to appear at all. This is Do Health's monitoring schedule, not a general recommendation for everyone.