What do your LDLs and HDLs really do?

We hear so much in the media about good and bad cholesterol, but do you really know what the hype is about and and how to apply it to your daily life? LDLs are considered the bad guys because they are the main form of cholesterol that causes blockage in the arteries. The job of the HDLs is to transport cholesterol to the liver to be broken down. HDLs also help to prevent plaque build-up and inflammation. HDLs and LDLs both breakdown into oxidized lipids, and that is the state at which they get to work. The oxidized version of the LDLs is what clogs your arteries. With diet change, HDL and LDL levels can be affected by exercise.

A study was recently done that looked at HDL and LDL concentration of 24 top distance runners when running on a treadmill. These runners were given a specific treadmill protocol that included running in an anaerobic zone. The subjects blood was tested before the treadmill session and then repeated right after, 15 minutes, and 90 minutes after the treadmill session. All of the subjects consumed the same meal for breakfast.

At the initial blood testing after the treadmill session, both LDLs and HDLs were high but as time went on, the LDL levels decreased while the HDLs remained the same. Even more interestingly, the concentration of oxidized HDL lipids actually increased right after the session and remind high for 90 minutes and oxidized LDLs actually decreased. This shows that exercise actually slows the LDL breakdown process into lipids, meaning it decreased the rate of arterial build-up. With the oxidation rate higher in the HDL’s after exercise, these HDL’s can work more efficiently in the arteries to prevent blockage and decrease arterial inflammation.

Valimaki I, Vuorimaa T, Ahotupa M, Vasankari T. Strenuous physical exercise accelerates the lipid peroxide clearing transport of HDL. European Journal of Physiology. June 2016. 116:1683-1691.


Kathleen Leninger, DPT