Continuous and intermittent walking alters HDL(2)-C and LCATa

The purpose of this study was to determine if exercise, whether continuous (CE: completed all in one session) or intermittent (completed in either two (IE 2) or three (IE 3) exercise sessions) expending the same number of calories alters reverse cholesterol transport or low density lipoprotein (LDL) particle size.

Sixteen healthy (22±2.1 year old) men (VO(2) max=37.0±3.3mL/kg/min) randomly completed three exercise trials, CE, IE 2 and IE 3, expending 450 calories. Blood samples were drawn immediately post-exercise (IPE) and 24 and 48h following exercise and analyzed for total cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL-C), high density lipoprotein (HDL-C) and subfractions (HDL(2)-C, HDL(3)-C). Samples were also analyzed to determine LDL-C particle size, lecithin cholesterol acyl transferase activity (LCATa) and cholesterol ester transfer protein activity (CETPa).

HDL(2)-C increased significantly 48h post-exercise in the CE and IE 2 groups. Additionally, the IE 3 group had significant increases in HDL(2)-C at 24 (39%) and 48h post-exercise by 66%. This change in HDL(2)-C was significantly and positively correlated (r=0.62; p<0.05) to the changes in LCATa which increased compared to baseline at 48h post-exercise in the CE and IE 3 groups. No significant changes in LDL particle size or alterations in CETPa were seen.

The results of this study indicate that whether the exercise is continuous or intermittent, keeping calorie expenditure the same, causes significant changes in the HDL(2)-C subfraction, which was augmented by an increase in LCATa.