A Single Bout of Prolonged Exercise Increases VLDL-TG Clearance

Abstract

Hyperlipidemia manifested by increased plasma triglycerides (TG) has been suggested as one of the leading causes of cardiovascular disease development. One single exercise session reduces fasting triglycerides, however the exact mechanism for this response has not been clarified yet. PURPOSE: To examine the effect of a single, prolonged (90 min), moderate intensity (60% of VO2max) exercise bout on VLDL-TG turnover rate 12 hours later (EXE), compared to a fasting control period (CON). METHODS: Eight healthy young men (age 26.1 ± 4.8 yrs, BMI 25.3 ± 1.0 kg.m−2, body fat 20.1 ± 4 %, VO2max 38.7 ± 5.1 mL.kg−1.min−1) participated in the study. Fractional catabolic rate (FCR) of VLDL-TG was calculated for 8 hours following bolus injection of 2H5-glycerol, from the decay of the isotopic enrichment using the monoexponential approach. RESULTS: VLDL-TG concentration was 0.50 ± 0.19 and 0.32 ± 0.12 mmol.L−1 in the CON and EXE trials respectively (p < 0.01) and concentrations were maintained constant throughout the 8-hour kinetics for both trials (p = NS). Plasma NEFA were 0.48 ± 0.21 and 0.53 ± 0.12 μmol.L−1 and plasma insulin was 6.6 ± 1.7 and 5.8 ± 1.6 mIU.L−1, for the CON and the EXE trials respectively (p = NS). VLDL-TG secretion rate remained constant for both trials (3.75 ± 1.20 and 3.43 ± 1.40 μmol.min−1 for CON and EXE trials respectively, p = NS), whereas disappearance rate increased by 28.8% after the EXE trial (27.01 + 3.87 ml.min-1 for CON and 37.94 ± 10.70 ml.min−1 for EXE, p < 0.05). CONCLUSIONS: The observed decrease in VLDL-TG concentration after a brisk walking for 90 min, at 60% of VO2max is related to increased VLDL-TG clearance.