Effects of acute moderate-intensity continuous running on circulating oxyntomodulin concentrations in healthy men and...

Oxyntomodulin (OXM) is a gut-derived peptide hormone with anorexigenic properties that reduce food intake and increase energy expenditure. This study investigated the effect of a single bout of moderate-intensity running on OXM concentrations and whether OXM response were associated with appetite perceptions and energy intake. Twenty healthy adults (10 men, 10 women; age: 25 ± 4 years; BMI: 22.2 ± 2.0 kg m^-2) completed two randomised crossover trials: (1) 60-min treadmill running at 70% of peak oxygen uptake, and (2) rest control. Plasma OXM concentrations were measured at baseline (0 min), immediately post-exercise/rest, and every 30 min until 210 min. Appetite ratings were assessed throughout. Energy intake was measured from an ad libitum meal provided at 120 min. Linear mixed-effect models were used to examine the main effect of trial, time, and their interaction. OXM concentrations increased after the meal in both trials (p < 0.001), with no main effect of trial (p = 0.413) or trial-by-time interaction (p = 0.748). Pre-lunch OXM time-averaged incremental area under the curve (iAUC) was higher following exercise compared with control (0-120 min, mean difference = 16 pg mL^-1·min, p = 0.006), whereas no difference was observed across the full sampling period (0-210 min; p = 0.265). Exercise increased fullness at 60 min (mean difference = 13 mm, p = 0.019) and reduced relative energy intake compared with control (mean difference = 2056 kJ, p < 0.001). No associations were observed between OXM iAUC and appetite perceptions or energy intake (p ≥ 0.098). Moderate-intensity running did not alter OXM concentrations. Changes in OXM were not associated with appetite perceptions or energy intake, suggesting that OXM may not play a central role in exercise-induced appetite regulation. Research across different exercise modes, intensities, and durations is warranted.