Associations Between High-Density Lipoprotein Subfraction Profiles and Heart Rate Response Following Submaximal...

The association of HDL and its subfractional profile with cardiovascular health, particularly atherosclerosis, is well established; however, its association with post-exercise heart rate response remains underexplored. This cross-sectional study investigated whether HDL subfraction distribution is associated with post-exercise heart rate dynamics. We analyzed 304 adults, stratifying HDL into ten subfractions and 3 subclasses using the Lipoprint^® system. Heart rate was measured at rest (HR_rest), immediately after the YMCA 3-min step test (HR_aft), and during recovery (HR_5min and HR_10min) to calculate ΔHR. Multiple regressions were applied with False Discovery Rate correction. Participants with a more favorable post-exercise heart rate profile exhibited higher ApoA-I levels and favorable lipid ratios. Subfractions spanning the large and intermediate ranges (HDL-3 to HDL-5) were inversely associated with HR_aft, HR_5min, and ΔHR. In contrast, smaller, lipid-poor subfractions (HDL-7 to HDL-10) were associated with higher heart rates and a less favorable post-exercise response. Total HDL-C and subclass-level concentrations showed no significant association. These findings suggest that HDL particle size distribution may provide exploratory insight into exercise-related cardiovascular responses beyond conventional lipid metrics. Although limited by the use of a submaximal field test and manual heart rate assessment, these results support further investigation of HDL subfraction profiling in relation to post-exercise heart rate dynamics.