Influence Of Caloric Expenditure On Postprandial Triglyceride And Glucose Responses Following A High-carbohydrate Meal

Abstract

PURPOSE: To examine the effects of aerobic exercise expending 350 and 700 kcal of energy on postprandial triglyceride (Tg) and glucose responses following a high carbohydrate (CHO) meal. METHODS: Non-active individuals (n=9 women/4 men; age=22.8±3.7 yrs; Ht=169±10.4 cm; Wt=75.7± 22.4 kg; BMI=26.1± 5.8 kg/m2; VO2 max=34.1± 6.9 ml/kg/min) completed three trials in a random order: 1) control trial, 2) single exercise session expending 350 kcal (EX350), and 3) single exercise session expending 700 kcal (EX700). Exercise consisted of treadmill walking at 60% VO2 max until 350 and 700 kcal of energy had been expended. The control session consisted of seated rest. The morning after each experimental session, a fasting (12hr) blood sample was collected followed by consumption of a high-CHO liquid meal (2.44 g/kg of fat free mass (CHO), 0.33 g/kg FFM fat, and 0.56 g/kg FFM protein. Blood was collected again at 1, 2, 3, 4, 5, and 6 hrs post-meal and analyzed for (Tg) and glucose concentrations. The areas under the curve (AUC) were calculated for both (Tg) and glucose concentrations. A repeated measures ANOVA was used to determine statistical significance (p<0.05). RESULTS: Baseline glucose concentrations were not different between trials (p=0.71). Postprandial AUC for glucose concentrations were not different between trials (p=0.38) (rest=592.6±96.3 mg/dl; 350 kcal= 626.9±118.7 mg/dl; 700 kcal=602.6±70.0 mg/dl). Baseline Tg concentrations were not altered with exercise of 350 kcal or 700 kcal when compared with rest (p=0.94). Postprandial Tg concentrations following rest (937.3 ± 928.4 mg/dl) were not altered (p=0.37) following exercise of 350 kcal (807.1±605.1 mg/dl) or 700 kcal (867.3±672.6). CONCLUSION: The glucose and Tg responses following a high-CHO meal were unaffected by a prior exercise session. The postprandial Tg response to prior exercise is different from the effect of exercise on the postprandial Tg response following a high-fat meal. There was substantial inter-subject variability in the exercise-induced change in the TG response, with the exercise induced change in the Tg AUC ranging from -27.4 to +17.4%. This study was Supported by Texas Woman's University's Research Enhancement Program.