No Effect of Menstrual Phase on Appetite-Regulatory Parameters Following a Moderate-Intensity Exercise Session.

Introduction: Exercise interventions are less effective in generating weight loss in females compared to males suggesting that the menstrual cycle may be important. Fluctuations in ovarian hormones are proposed to alter the appetite-regulatory response to exercise across the menstrual cycle and no study has assessed the response in all distinct hormonal phases.

Purpose: To compare post-exercise appetite-regulating parameters following a single bout of MICT across three distinct menstrual phases.

Methods: Thirteen females (24 ± 4 y; 24.8 ± 5.4 kg·m-2) completed 30 min of moderate-intensity continuous training (MICT) running in the follicular phase (FP), ovulatory phase (OP), and luteal phase (LP). Acylated ghrelin, active glucagon-like peptide-1 (GLP-1), plasma glucose, insulin, blood lactate, and appetite perceptions were measured pre-exercise, 0 min, 30 min, 60 min, and 120 min post-exercise. Energy intake was recorded for a 3-day period (day before, of, and after each session).

Results: Acylated ghrelin was not different across phases (p = 0.672, ηp2 = 0.032) and only showed a main effect of time (p = 0.006, ηp2 = 0.757) increasing with time. Active GLP-1 was not different across phases (p = 0.735, ηp2 = 0.025) and had a main effect of time (p < 0.001, ηp2 = 0.569) decreasing with time. Appetite perceptions were not different across phases (p = 0.577, ηp2 = 0.045) and exhibited a main effect of time (p < 0.001, ηp2 = 0.786) increasing with time. There was no effect of phase for energy intake (p = 0.544, ηp2 = 0.065). Finally, there were no differences in plasma glucose, insulin, or blood lactate across phases (p > 0.421, ηp2 < 0.070).

Conclusions: There were no divergent appetite responses following MICT running across three hormonally distinct phases (mid-FP, OP, mid-LP) of the menstrual cycle in young eumenorrheic females not using oral contraceptives.