Influence of oestradiol on exercise induced muscular damage and heart rate variability in a non‐trained healthy population

This study evaluates in non-trained healthy women the influence of oestradiol (E2) on exercise induced muscular damage (EIMD) and performance. Thirty-six young healthy women performed a step-exercise until exhaustion, assessing the number of repetitions, pain perception and well-being (questionnaires, 15 min and at 48 h post-exercise), blood pressure (sphygmomanometer) and heart rate variability (HRV; H10-polar band) were measured at rest and 15 min post-exercise. Plasma samples were taken at rest and 2 h post-exercise, assessing interleukin (IL)-1α, IL-6, IL-1ra, IL-10 (multiplex ELISA), creatine kinase (CK) and lactate dehydrogenase (LDH) activities, and E2 (spectrophotometry). Statistical analysis was performed comparing women with low E2 (<40 pg/mL; n = 18) and high E2 (≥40 pg/mL; n = 18). The number of repetitions was not different between groups and did not correlate with E2. Compared to the low-E2 group, the high-E2 group had significantly smaller lower-body pain perception at 2 h and scored higher in well-being at 48 h. IL-6 and IL-10 levels 2 h post-exercise did not differ between groups, but both cytokines positively correlated with E2. LDH, but not CK, was lower in the high-E2 group and negatively correlated with E2. Blood pressure at rest negatively correlated with E2. Total pain at 48 h positively correlated with LDH and negatively with IL-10, and the opposite correlations were found with well-being. No differences between groups or E2 correlations were found in time-domain or frequency-domain HRV parameters at rest or after exercise. In conclusion, in non-trained women, oestrogen levels influence EIMD, reducing pain perception. These effects could be related to E2 actions on membrane protection and accelerating muscle fibre regeneration through IL-6/IL-10 myokine signalling. According to these data, oestrogen does not appear to influence HRV, and the role of progesterone deserves further attention.