The Creatine Kinase, Estrogen and Progesterone Responses to a Single Bout of High-intensity Interval Training in Inactive Young Women

  studies have demonstrated a protective effects of female sex hormones against muscle membrane disorders in compared to men following high-intensity exercises. The aim of this study was to evaluate the creatine kinase, estrogen and progesterone responses to a single bout of high-intensity interval training (HIIT) and as well as the relationship between sex hormones and CK response in inactive young women.

24 young inactive women (18–30-year-old and VO2max<30 ml/kg/mil) with regular menstrual cycles were randomly divided in 2 groups: HIIT or experimental (n = 12) and control (n = 12). The experimental group performed HIIE by a treadmill with a slope of 2% in six repetitions (3 sets) for one minute with an intensity of 90-95% HRmax with a total rest time of ten minutes between sets and repetitions. Before and ten minutes after exercise, blood samples were collected to measure creatine kinase (CK), estrogen, progesterone and hemoglobin (plasma shift). Data analysis was performed by using ANCOVA test and linear regression at the statistical level of P <0.05 and SPSS 23.

 Significant increases were recorded in CK and estrogen in experimental group compared with control group (P<0.05). There was a significant relationship between baseline progesterone levels and CK response (P= 0.016). According to the results of linear regression, CK response to HIIE in women can be predicted based on the baseline progesterone level (31.8%).

 Given that progesterone led to decreased CK response, it seems that it is better to perform vigorous intensity exercises in the menstrual phases with high levels of progesterone (mid-luteal phase) in order to reduce further muscle damage in women.    However, due to the low predictive power of progesterone (31.8%), more studies are needed with more samples.