A Comparison of Intermittent and Continuous Exercise Bouts at Different Intensities on Appetite and Postprandial Metabolic Responses in Healthy Men

Exercise intensity affects many potential postprandial responses, but there is limited information on the influence of exercise modality. Therefore, the aim of this study was to investigate if the nature of exercise at two different intensities would affect gastric emptying rate (GER), appetite and metabolic responses following ingestion of a semi-solid meal. Twelve healthy men completed, in a random order, four 60-min cycles at 60% VO2peak(MOD), 40% VO2peak(LOW) and in a continuous (CON) or intermittent (INT) manner. INT consisted of 20 x 1-min exercise bouts with 2-min rest breaks. INT and CON were matched for total work output at each intensity. GER of the post-exercise meal was measured for 2 h using the 13C-breath method. Blood glucose, substrate utilisation and appetite ratings were measured at regular intervals throughout all trials and 24-h energy intake (EI) post-trials was assessed. GER-Delta over Baseline (DOB) was lower (p< 0.05) on MOD-INT vs. MOD-CON from 30-120 min post-meal. Blood glucose was higher mid-exercise (p< 0.05) on MOD-INT vs. MOD-CON. Although post-exercise LOW-CON was significantly higher than LOW-INT (p< 0.05), blood glucose was also higher 30-min post-meal ingestion on both CON trials compared to INT (p< 0.001). No interaction effect was observed for perceived appetite responses 2 h after meal ingestion (allp> 0.05). 24-h post-trial EI was similar between LOW-CON vs. LOW-INT (p> 0.05), although MOD-INT vs. MOD-CON 3500 +/- 1419 vs. 2556 +/- 989 kCal:p< 0.001 was elevated. In summary, MOD-INT exercise delays GER without stimulating perceived appetite in the 2 h period after meal ingestion, although EI was greater in the 24-h post-trial.