Purpose: The purpose of this study was to examine the effects of previous exercise on metabolic, hormonal, and endothelial responses to an oral fat-tolerance test (OFTT).
Methods: Twelve healthy, recreationally trained men (age = 22.3 ± 2.5 yr, weight = 80.7 ± 12.4 kg, BMI = 25.1 ± 3.1 kg·m−2) volunteered for this study. In a crossover fashion, subjects completed three OFTT trials that involved no exercise (NoEx) or exercise performed 16 h (EX-16) or 4 h (EX-4) before the ingestion of a meal (13 kcal·kg−1 and 1.4 g of fat per kilogram of body weight). Blood was collected before and after the meal and hourly for 6 h. Brachial artery reactivity was measured using ultrasound before and at 2, 4, and 6 h after the meal. Dietary intake and exercise were standardized 4 d before the OFTT. The exercise session consisted of six resistance exercises and 30 min of running on a treadmill. The washout period between trials was, on average, 5 d.
Results: Compared with NoEx, there were significant (P < 0.05) decreases in triglyceride area under the curve (AUC) during EX-16 (−26%) and EX-4 (−15%). Compared with NoEx, there were decreases in insulin AUC during EX-16 (−7%, P < 0.05) and EX-4 (−5%, NS). EX-4 resulted in a significantly larger fasting arterial diameter than EX-16 and NoEx, but there were no other significant effects on endothelial function. Lipemic variables did not show correlations with endothelium function for any of the trials.
Conclusion: An acute exercise session, regardless of the time point chosen (i.e., EX-16 or EX-4), reduced to a similar extent the total and incremental lipemic responses compared with the NoEx condition.