Kamryn Shapiro (kamryneden@mail.weber.edu)

Exercising has shown to increase HDL-C levels in most populations, however it is uncertain if it has an effect in structural apolipoproteins such as apolipoprotein A1( Apo-A1) expression and secretion. Cross-country athletes undergo a period of tapering before competition resulting in reduced physical activity. The purpose of this study was to determine if the changes in physical activity that cross country athletes experience during the season and in preparation for competition affects their HDL-C. We hypothesize that the tapering period will result in reduced HDL-C and its structural apolipoproteins.
Twenty seven D-I cross-country athletes, ages 19 to 25 years old, were followed for one season (four months). Blood was collected at the beginning of the season and analyzed for HDL-C levels through enzymatic spectrophotometry using the Alfa Wasserman Ace Axcel® biochemistry analyzer. Apo-A1 and Apo-CIII were measured through Luminex® MAGPIX® multiplex assays. Paired-samples t-test comparing the preseason (pre) vs postseason (post) values was performed using IBM® SPSS Statistics 25.
HDL-C levels decreased significantly from pre = 64.2 ± 2.7, vs post = 60.7 ± 2.5 mg/dL p = 0.03. Apo-A1, 92.3 ± 6.5 vs 88.8 ± 6.8, p = 0.23 and Apo-CIII 13.8 ± 0.1 vs 13.3 ± 0.5, p = 0.37 showed no statistical difference from pre vs post.
Our study shows that HDL-C levels are decreased by a period of time as short as 4 months. However, we did not observe a change on apolipoproteins A1 or CIII. These findings suggest that although exercise can modulate lipidation of the HDL particle through the process of cholesterol esterification in the reverse cholesterol transportation (RCT), Apo-A1 expression and secretion may be modulated independently of this process as we did not observe any changes in apolipoprotein concentrations.