Sex differences in postprandial lipaemia after acute high-intensity interval running in young people

Acute exercise reduces postprandial triacylglycerol concentrations ([TAG]) in boys and girls; however, it is not known whether between-sex differences exist in response to exercise. Fifteen boys (mean(SD): 11.8(0.4) years) and sixteen girls (12.1(0.7) years) completed two, 2-day conditions. On day 1, participants rested (CON) or completed 10×1 min high-intensity interval runs at 100% maximal aerobic speed with 1 min recovery (HIIR). On day 2, participants consumed a standardised breakfast and lunch over a 6.5-h period during which seven capillary blood samples were collected. Based on ratios of the geometric means (95% CI for ratios), fasting [TAG] was 32% lower in boys than girls (-44 to -18%, ES=1.31, P<0.001), and 12% lower after HIIR than CON (-18 to -5%, ES=0.42, P=0.003); the magnitude of reduction was not significantly different between the sexes (8% (ES=0.36) vs. 15% (ES=0.47), respectively; P=0.29). The total area under the [TAG] versus time curve was 27% lower in boys than girls (-40 to -10%, ES=1.02, P=0.005), and 10% lower after HIIR than CON (-16 to -5%, ES=0.36, P=0.001); the magnitude of reduction was similar between the sexes (11% (ES=0.43) vs. 10% (ES=0.31), respectively; P=0.87). The small-moderate reduction in postprandial [TAG] after HIIR was similar between the sexes.