Effects of low and moderate intensity treadmill walking on postprandial lipaemia in healthy young adults

We have previously shown that the lipaemic response to a fatty meal was reduced when prolonged (2 h) low intensity exercise was taken some hours before eating. The purpose of this study was to test the hypothesis that the effect is quantitatively greater after exercise of moderate intensity than after exercise at low intensity. Six men and six women, mean age 26.9 (SEM 1.5) years, took part in three trials, each conducted over 2 days; on the afternoon of day 1 of each of two exercise trials the subjects walked on a treadmill for 90 min at either 31 (SEM 1) % or 61 (SEM 1) % of maximal oxygen uptake, i.e. low and moderate intensity, respectively; on the control trial the subjects refrained from exercise on day 1. On the morning of day 2 of each trial they ingested a test meal (1.28 g fat, 1.44 g carbohydrate, 76 kJ energy . kg(-1) body mass); blood samples were obtained in the fasted state and for 6 h after the meal. Fasting serum triacylglycerol concentration and the area under the postprandial triacylglycerol-time curve were lower than in the control trial (P < 0.05) after moderate intensity walking but not after low intensity walking. The results suggest that the mitigation of the lipaemic response to a meal high in fat and carbohydrate is related to the intensity and/or the energy expenditure of the preceding exercise.