The goal of this clinical trial is to evaluate the impact of moderate aerobic exercise on menstrual symptom management in sedentary women both using and not using hormonal contraceptives. The main questions it aims to answer are:

Is there a reduction in physical and/or psychological menstrual cycle related symptom burden with participation in moderate aerobic exercise for sedentary women using and not using hormonal contraceptives?

Is there a difference in physical and/or psychological menstrual cycle related symptom burden between hormonal contraceptive and non-hormonal contraceptive users?

Is a moderate aerobic exercise intervention more effective in reducing physical and/or psychological menstrual related symptom burden for sedentary women using or not using hormonal contraceptives?

Participants will:

• Have their body composition assessed using dual energy X-ray absorptiometry pre and post exercise intervention.
• Complete a Menstrual Symptom Index (MSi) to report daily menstrual cycle related symptom burden in addition to the Premenstrual Symptom Screening Tool (PSST) and Heavy Menstrual Bleeding (HMB) questionnaire monthly.
• Utilize an at-home monitor to test urinary luteinizing hormone, estrone-3-glucuronide, and pregnanediol glucuronide approximately 10 times per month and report menstrual cycle length.
• Record physical activity habits by continuously wearing a wrist-based accelerometer and chest-strap heart rate monitor during planned aerobic exercise sessions and complete the International Physical Activity Questionnaire (IPAQ) monthly.
• Maintain their usual sedentary activity habits for one menstrual cycle followed by completion of an exercise intervention designed to progress individuals to meet minimum recommended aerobic physical activity guidelines of 150 minutes per week set by the American College of Sports Medicine for two menstrual cycles.

Inclusion Criteria:

• premenopausal (defined as having regular menstrual periods every 21-35 days)
• either not using hormonal or non-hormonal contraceptives (i.e., intrauterine device) for the past 6 months OR using combined oral contraceptives (i.e., those that contain progesterone and estrogen) for at least the past 6 months
• not currently pregnant or trying to become pregnant
• sedentary lifestyle (score of "low activity/inactive" assessed using the IPAQ)
• have self reported menstrual cycle symptoms (symptoms reported on the PSST or MSi)
• do not have a medical diagnosis or signs/symptoms of diabetes, cardiovascular, or renal disease and are able to participate in moderate intensity physical activity without physician clearance

Exclusion Criteria:

• becoming physically active defined as scoring higher than "low activity/inactive" on the IPAQ during the first month of the study
• non compliance with instructions provided for the moderate aerobic exercise intervention (i.e., not adhering to predetermined intensity heart rate targets) or miss more than 25% of exercise sessions in either intervention month
• becoming pregnant during enrollment
• being diagnosed with a cardiovascular, metabolic, or renal disease that would require physical clearance to participate in moderate intensity aerobic physical activity
• begin using hormonal or non-hormonal (i.e., intrauterine devices) contraceptives if assigned to the arm not using hormonal contraceptives
• either begin a different type of contraceptive or discontinue combined hormonal contraceptive use if assigned to the hormonal contraceptive arm