Inclusion Criteria:  Female participants will be recruited for the study (BMI of <29.9 kg/m2). Ages of 18 and 45 years old Weight stable (± 2 kg) for the last three months Regularly endurance training on most days of the week for at least one hour for the last two years No exclusion will be made for race or socioeconomic status Participants will be eumenorrheic and premenopausal  Exclusion Criteria:  Resting blood pressure above 160 mmHg systolic or 100 mmHg diastolic Type 1 or type 2 diabetes; 3) Other medical problems in which exercise is contraindicated chronic infections Diagnoses, signs, or symptoms of cardiovascular disease Respiratory disease Musculoskeletal disease Musculoskeletal injuries in the last six months that would prevent them from engaging in endurance training. Pregnant or lactating and must have a Irregular menstrual cycle Smoking Diagnosed eating disorders