Acute High-Intensity Interval Cycling Improves Postprandial Lipid Metabolism

Purpose This study aimed to examine the effects of two exercise regimes on physiological and postprandial lipemic responses. Methods Thirty-six active men (peak oxygen uptake [VO2peak], 46.5 6.4 mLkg(-1)min(-1)) were randomly assigned to a high-intensity interval exercise (HIIE), involving 10 x 60 s cycling at 85% VO2peak interspersed with 120 s recovery; a moderate-intensity continuous exercise (MICE), involving 50 min continuous exercise at 65% VO2peak; and a nonexercise control (Con). In the next morning after evening exercising, fasting blood samples were obtained. Additional blood samples were obtained 1-4 h after eating a given high-fat meal that based on participants' body mass. Carbohydrate and fat oxidation rates were measured before and after the meal. Results After exercise, glucose and insulin concentrations decreased by 33% and 70% in MICE compared with those in HIIE (P = 0.00-0.03). During the 1- to 2-h postprandial periods, the fat oxidation rate increased by 24%-37% in HIIE that that in MICE and Con (P = 0.01-0.03); however, the carbohydrate oxidation rate was not significantly different among the conditions (P = 0.28). During the postprandial period, insulin (P = 0.02-0.04) and triglyceride (P = 0.02-0.03) concentrations were lower in HIIE than those in MICE and Con. No difference was observed in free fatty acid or the total areas under the curve of triglyceride and free fatty acid among the conditions (P = 0.24-0.98). Conclusion Acute MICE improved glucose and insulin metabolism immediately after exercise. However, HIIE performed in the evening exerts more favorable effects than MICE for decreasing postprandial insulin and triglyceride levels and increasing fat oxidation in the next morning.