Elevated high-density lipoprotein cholesterol in endurance athletes is related to enhanced plasma triglyceride clearance

We compared the clearance rate (K₂) of plasma triglycerides (TG) following the intravenous (IV) infusion of a fat emulsion in 13 male endurance athletes (age 33 ± 5.6 years, mean ± SD) and 12 sedentary men (33 ± 5.6 years). The athletes had lower fasting triglycerides (TG) (75 ± 30.4 mg/dL v 125 ± 52.5 mg/dL) and higher high-density lipoprotein (HDL) cholesterol concentrations (64 ± 16.2 mg/dL v 42 ± 9.4 mg/dL) than the sedentary subjects (P < .01 for all). The higher HDL concentrations were due to increases in both the HDL₂ and HDL₃ subfractions. K₂ in the athletes was 92% higher than that in the sedentary men (4.8 ± 2.3 %/min v 2.5 ± 0.7 %/min, P < .01), but there was no difference in postheparin lipoprotein lipase activity (LPLA) between the groups (P > .05). K₂ was positively correlated with LPLA (r = .51) and inversely related to fasting TG concentrations (r = -.73, P < .01 for both). Furthermore, K₂ was directly related to HDL (r = .75), HDL₂ (r = .72), and HDL₃ (r = .60) cholesterol concentrations (P < .01 for all). These data suggest that the low TG levels in endurance athletes result at least in part from increased TG removal and that the elevated HDL concentrations of endurance athletes are related to enhanced fat clearance.