High-intensity intermittent exercise induces a potential anti-inflammatory response in healthy women across the menstrual cycle.

Abstract

This observational study aimed to examine cytokine responses to high-intensity intermittent exercise (HIIE) in the follicular and luteal phases of the menstrual cycle. Fourteen healthy women (24±2years; body mass index [BMI]: 22.8±1.9kg⋅m2; maximal oxygen consumption [V̇O2max]: 41.5±4.1mL⋅kg-1⋅min-1) with regular menstrual cycles were randomly assigned to 4 experimental sessions, 2 during the follicular and 2 during the luteal phase. V̇O2max and maximum aerobic velocity (MAV) were determined prior to the experimental sessions through a graded exercise test during both follicular and luteal phases. Seventy-two hours after having completed the graded exercise test, all participants performed a HIIE session (10 x 1-min sprints with 1min of rest) at 90% of their MAV. Serum concentrations of TNF-α, IL-6, IL-10 and IL-17 were measured before (Pre), immediately after (Post) and 1h after (1h Post) the HIIE sessions. Pre-exercise concentrations of TNF-α and IL-10 were significantly higher in the luteal phase compared to the follicular phase (P<0.01), with no differences seen on IL-6 and IL-17, demonstrating an altered inflammatory status in the luteal phase. There was a significant interaction for IL-10 concentration (P<0.01) with reductions in both luteal (Pre vs Post, 95%CI: 1.086 to 6.156; and Pre vs 1h Post, 95%CI: 1.720 to 9.013, P<0.01) and follicular phase (Pre vs 1h Post, 95%CI: 0.502 to 7.842, P<0.05). Despite no significant phase×time interaction for TNF-α concentration, its concentration at 1h Post was significantly lower compared to Pre in the luteal phase analysis (Pre vs 1h Post, 95%CI: 0.71 to 14.06; P<0.05). These results are in agreement with IL-10 responses, highlighting a reduction on the inflammatory status after exercise. Mostly during the luteal phase, high-intensity intermittent exercise modulates cytokine responses, thus impacting exercise recovery. In this scenario, high-intensity intermittent exercise emerges as a non-pharmacology strategy to regulate inflammatory responses on healthy women who were affected by an inflammatory state given their menstrual cycle.