Resting Metabolic Rate and Diet-Induced Thermogenesis during Each Phase of the Menstrual Cycle in Healthy Young Women.

Abstract

The effects of the menstrual cycle on resting metabolic rate (RMR) and diet-induced thermogenesis (DIT) were studied in nine healthy young women aged 18-19 years. All subjects were eumenorrheic, with regular menstrual cycles ranging from 28 to 32 days. RMR and DIT were measured in the mid follicular phase and in the mid luteal phase. On the experimental days, subjects fasted overnight; then the RMR was measured by indirect calorimetry. For the measurement of DIT, subjects were fed a meal containing a uniform amount of energy (2.53MJ) eaten within 15 min, and then indirect calorimetry was performed during rest for 180min. The RMR was significantly higher in the luteal phase than in the follicular phase (67.0 vs. 62.5J/kg/min, p<0.01). DIT was also significantly higher in the luteal phase (4.0 vs. 3.2kJ/kg/3h, p<0.01). The postprandial respiratory exchange ratio was slightly lower in the luteal phase than in the follicular phase (0.78 vs. 0.81). These results suggest that the menstrual cycle phase affects both the RMR and DIT. Higher postprandial energy expenditure and fat utilization in the luteal phase may be related to sympathetic and endocrinal actions.