What the H... is HDL?
Lipo -protein lipo = fat, protein = protein: proteins that carry fat.
Cholesterol is transported in the blood by lipoproteins. It goes to organs that need it, like the adrenals to make hormones, and comes back to the liver for excretion.
Lipoproteins come in various sizes, large (High Density Lipoprotein, HDL), small (Low Density Lipoprotein, LDL), and very small (Very Low Density Lipoprotein, VLDL).
I think of lipoproteins as fleets of trucks (lorries in UK!).
HDLs are big trucks, pantechnicons. They are big enough to carry the cholesterol inside the truck. None sticks out to be snared by the cholesterol receptors in the pores of the arteries.
LDLs are smaller trucks, like big pick-up trucks. They carry cholesterol in the back but it is exposed to the walls of the arteries where it can fall off and cause plaque.
VLDLs are tiny pick-ups. Cholesterol is more likely to fall off in an artery than to make it to the depot (liver) for destruction.
You want your cholesterol to be carried on the biggest truck possible! Increase your HDL.
How to increase HDL.
Lipoproteins also carry other fats in particular triglycerides. Triglycerides are oily fats used as fuel.
How exercise increases HDL.
When you exercise your muscles first use sugar for energy. This lasts only a few minutes. Then the body uses glycogen which is a molecule made up of lots of sugars linked in chains. Glycogen is stored in muscles and your liver. The muscles lop sugars off the chain and use them for energy. Glycogen lasts a bit longer than sugar when you exercise but by 8-12 minutes after starting your glycogen store starts getting low. Next your body uses free-fatty-acids. These contain a lot of energy. They include triglycerides and are carried on HDL.
The more you exercise the more delivery trucks you need to carry the free fatty acids to the muscles.
PROLONGED EXERCISE (BEYOND 8-12 MINUTES) INCREASES HDL.
Some people have genetically low HDL and no matter how they exercise their HDL stays low. THEY NEED STATINS.
