title: Are the reductions in triacylglycerol and insulin levels after exercise related?
abstract: Moderate exercise improves insulin sensitivity and reduces triacylglycerol (triglyceride; TG) concentrations. We hypothesized that changes in insulin sensitivity are an important determinant of exercise-induced changes in postprandial TG concentrations. Altogether, 38 men and 43 women, all of whom were normotriglyceridaemic and normoglycaemic, each underwent two oral fat tolerance tests with different pre-conditions: control (no exercise) and prior exercise (90 min of exercise at 60% of maximal O(2) uptake the day before). Venous blood samples were obtained in the fasting state and for 6 h after a high-fat mixed meal. In the control trial there were significant correlations between log fasting TG concentration and log fasting insulin concentration (r=0.42, P<0.0005) and between log postprandial TG response (area under the curve) and log postprandial insulin response (r=0.48, P<0.0005). Prior exercise reduced the fasting TG concentration by 18.2 +/- 2.2% (mean +/- S.E.M.) (P<0.0005), the postprandial TG response by 21.5 +/-1.9% (P<0.0005), the fasting insulin concentration by 3.8 +/- 3.1% (P<0.01) and the postprandial insulin response by 11.9 +/- 2.5% (P<0.0005). However, there was no relationship between the exercise-induced changes in log fasting TG and log fasting insulin (r=0.08, P=0.50), nor between the exercise-induced changes in log postprandial TG response and log postprandial insulin response (r=0.04, P=0.70). These data suggest that the reductions in fasting and postprandial TG levels elicited by a session of moderate-intensity exercise are not mediated by an increase in insulin sensitivity.
authors.affiliation: Department of Pathological Biochemistry, Glasgow Royal Infirmary, Glasgow G31 2ER, UK. j.gill@clinmed.gla.ac.uk
authors.forename: Jason M R
authors.initials: JM
authors.lastname: Gill
authors.forename: Sara L
authors.initials: SL
authors.lastname: Herd
authors.forename: Natassa V
authors.initials: NV
authors.lastname: Tsetsonis
authors.forename: Adrianne E
authors.initials: AE
authors.lastname: Hardman
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D019540:Area Under Curve; D008076:Cholesterol, HDL / Q000097:blood; D004041:Dietary Fats / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005215:Fasting / Q000502:physiology; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period / Q000502:physiology; D014280:Triglycerides / Q000097:blood*
chemical_list: D008076:Cholesterol, HDL; D004041:Dietary Fats; D007328:Insulin; D014280:Triglycerides