Effects of Resistance Training on Substrate Metabolism During the Menstrual Cycle

Acute Effects of Resistance Training on Substrate Metabolism During Different Phases of Menstrual Cycle

This research project's objective is to investigate substrate metabolism behavior in response to the RT during different phases of the menstrual cycle.

Based on the literature the investigators hypothesize an increase in fat oxidation in early follicular phase(EFP) and late follicular phase (LFP) when compared to early luteal phase (ELP) and late luteal phase (LLP). Given the lack of research in exercise and menstrual cycle - especially in resistance training - results are uncertain unless the investigators base their hypotheses only on the general physiological effects of sex hormones (without exercise). In this case, the investigators expect to see a reduced carbohydrate utilization and an increased utilization of fats in EFP and LFP. In addition, the intervention is focused on muscular endurance and, therefore, it is expected to see a higher reliance on aerobic pathways. It is expected that the effects of the intervention will be added to the effects of estrogens, with increasing fat oxidation when estrogen levels are higher. Lastly, a comparison of fat oxidation levels obtained on each sub-phase would reveal if there are differences in the magnitude of the effect of distinct concentrations of estrogen and progesterone.

Inclusion Criteria:

• Females with BMI-18.5-34.99 and between 18-45 years, with normal menstrual cycle defined as 28-30 days cycles +-3 days.
• Including higher BMI participants might alter the results as increased body fat has been linked to changes in different hormonal levels (not only sex hormones) and that might influence substrate utilization.
• Sedentary .or physically active for 2 days a week or less.

Exclusion Criteria:

• • Musculoskeletal injuries,

  • cardio-respiratory conditions,
  • metabolic conditions,
  • irregular menstrual cycle,
  • menstrual dysfunction or unusual sex hormone levels,
  • on contraceptives,
  • on medication that alter hormonal or cardio-respiratory responses,
  • pre-menopausal symptoms,
  • on moderate to high-intensity exercise regime more than 2d/week.
  • All these exclusion criteria are chosen because any one of the listed criteria above can alter the responses and/or affect the safety of the subject during their participation in the study.