A single bout of brisk walking increases basal very low-density lipoprotein triacylglycerol clearance in young men

Very low-density lipoprotein triacylglycerol (VLDL-TG) turnover rate was evaluated in the morning, 12 hours after a single bout of brisk walking (90 minutes at approximately 60% of V̇o2max; EXE), compared to a resting control period (CON) in 10 recreationally active men. VLDL-TG fractional catabolic rate was calculated from the decay in isotopic enrichment after a bolus injection of [2H5]glycerol. Plasma VLDL-TG concentration was 24% lower in the morning after the EXE trial compared to control (0.47 ± 0.04 and 0.36 ± 0.04 mmol L−1, for CON and EXE, respectively; P < .01). Serum insulin (7.4 ± 0.7 and 5.6 ± 0.4 mIU L−1, CON and EXE, respectively; P < .05) and plasma glucose (5.6 ± 0.1 and 5.4 ± 0.1 mmol/L, CON and EXE, respectively; P < .05) concentrations were also significantly lower in the EXE trial. Insulin sensitivity (homeostasis model assessment [HOMA] index) was improved by 27% in EXE compared with the CON trial (P < .05).VLDL-apolipoprotein B-100 and plasma fatty acid concentrations were similar in the two trials. Hepatic VLDL-TG secretion rates were not significantly affected by exercise (13.1 ± 1.2 and 13.2 ± 1.6 μmol.min−1 for the CON and EXE trials, respectively), whereas VLDL-TG clearance rate increased by 36% (28.1 ± 1.3 and 38.1 ± 3.5 mL.min−1 for the CON and EXE trials, respectively; P < .05). It is concluded that the decrease in fasting plasma VLDL-TG concentration observed 12 hours after brisk walking is related mainly to increased VLDL-TG clearance from plasma.