IL‐6 and Delayed Onset Muscle Soreness Do Not Vary During the Menstrual Cycle

Abstract

The purpose of this study was to determine if a difference in interleukin‐6 (IL‐6) and delayed onset muscles soreness (DOMS) exists in the early follicular (EF) and mid‐luteal (ML) phases of the menstrual cycle in a group of competitive female distance runners following exhaustive running. Nine well‐trained, female endurance runners whose mean age was 26.8 ± 4.3 yr participated in this study. Each subject performed one 75 min high intensity interval running session during the EF phase (low estrogen and progesterone) and once during the ML phase (elevated estrogen and progesterone) of the menstrual cycle. Venous blood was collected before and after exercise to determine the IL‐6 concentration. Pre‐exercise plasma was assayed for estrogen and progesterone concentrations. Estrogen and progesterone levels were significantly reduced in the EF phase (68.44 ± 28.73 pg/ml and 8.70 ± 3.42 ng/ml, respectively) when compared to the ML phase (85.78 ± 14.75 pg/ml and 13.73 ± 2.54 ng/ml, respectively) of the menstrual cycle (p < 0.05). Plasma IL‐6 levels increased from pre to post exercise in the EF and ML phases of the menstrual cycle (p < 0.001). However, IL‐6 and DOMS were not higher in the EF phase than in the ML phase. Furthermore, there was no relationship between the level of IL‐6 and DOMS. The results suggest that menstruating female runners need not vary training throughout the month in order to reduce DOMS.