REDUCTION IN POSTPRANDIAL LIPEMIA AFTER WALKING - INFLUENCE OF EXERCISE INTENSITY

This study compared the effects of low and moderate intensity walking on postprandial lipemia, holding energy expenditure constant. Nine hea lthy normolipidemic subjects (5 men, 4 women; age 27.7 +/- 0.9, fastin g plasma triacylglycerol 0.95 +/- 0.18 mmol . l(-1), mean SEM) who wer e physically active but not endurance-trained undertook three trials, each over 2 d, in a balanced design. On the afternoon of day 1 they ei ther refrained from exercise (Control), walked for 3 h at low intensit y (Walk low, 32 +/- 1% V over dot O-2max) or walked for 1.5 h at moder ate intensity (Walk moderate, 63 +/- 1% V over dot O-2max). The follow ing morning, after a 12-h fast, they consumed a high-fat meal (1.3 g f at, 1.2 g carbohydrate, 0.2 g protein, 76 kJ energy per kg body mass). Blood and expired air samples were obtained before the meal and for 6 h afterward. Postprandial lipemia (total area under triacylglycerol c oncentration vs time curve) was lower than control after low intensity walking as well as after moderate intensity walking (both P < 0.05) b ut did not differ between the two walking trials (Control, 8.09 +/- 1. 09 mmol . l(-1) h; Walk low, 5.46 +/- 0.63 mmol . l(-1) h; Walk modera te, 5.53 +/- 0.58 mmol . l(-1). h). The increase in energy production following the test meal did not differ between trials, but fat oxidati on was increased in the fasting and postprandial states for both walki ng trials, compared with control (P < 0.05).