Beetroot Supplementation in Women Enjoying Exercise Together

An increasing body of evidence has supported acute benefits of beetroot juice including lowered blood pressure and greater muscle oxygenation during exercise. Thus, consumption of beetroot juice prior to exercise may alter the perceptual difficulty for a given exercise bout -- possibly resulting in an individual exercising at a greater intensity (without the commensurate increase in discomfort). The investigators propose that repeated exposure to a relatively greater exercise stimulus (via beetroot juice) may elicit more robust cardio-metabolic adaptations compared to exercise training alone (i.e., without beetroot juice). Possible findings could inform a larger randomized clinical trial to determine if pre-exercise beetroot juice supplementation is an effective strategy to promote health related benefits.

The investigators will examine the effects of pre-exercise beetroot juice coupled with 8 weeks of supervised exercise training among post-menopausal (75 and younger) women. Qualified individuals will be required to complete an initial screening visit as well as three baseline visits (Visits 1-2). Participants will undergo a series of tests including: dual-energy X-ray absorptiometry scan, bioelectrical impedance analysis, exhaled fraction of nitric oxide, health-related questionnaires, and pulse wave velocity. Participants will also be asked to perform leg muscle function and walking tests. Following the completion of Visits 1-2, participants will attend supervised exercise training sessions 3x/week for 8 weeks. Within 2-6 days from the last exercise training session, participants will repeat the same measurement procedures.

The primary objective involves elements of feasibility (e.g., recruitment, retention, adherence, and adverse event) and to generate preliminary effect sizes for 8 weeks of exercise training for two groups: control and EX+BR. Secondary objectives involve preliminary effect sizes for pre-post changes in distance covered during the 6-minute walk test, changes in endothelial-dependent vasodilation, and biomarkers of cardiovascular health.

Inclusion criteria

• Post-menopausal women (self-report)
• Between the ages of 18-75 years (confirmed by birth date listed on participant's driver license at screening visit)
• Physician's clearance for study participation (required prior to baseline testing)
• English-speaking
• Body mass index between 25.0 to 39.9 kg/m^2 (measured on-site at screening visit)
• Able to ambulate without assistance

Exclusion criteria

• Unable to provide informed consent
• 18-75 of age (confirmed by birth date listed on participant's driver license at screening visit)
• Body mass index < 25.0 or >39.9 kg/m^2 (measured on-site at screening visit)
• Greater than stage II hypertension (i.e. >159/99 mm Hg)
• Current smoker (self-report)
• Currently pregnant, lactating, or trying to become pregnant (self-report)
• Habitually exercise training >= 3 times per week (self-report)
• Significant orthopedic limitations or other contraindications to strenuous exercise
• Live or work >50 miles from Bloomington study site or do not have transportation to the study site
• Anticipate elective surgery during the study period
• Plan to move residence or travel out of the local area during the study period
• History of major metabolic disease (e.g. Type I diabetes, Type II diabetes, thyroid disorders)
• Current use of anti-coagulants (e.g. Coumadin or Warfarin)
• Current use of prescription medications that affect heart rate or blood vessel dilation (e.g. phosphodiesterase-5 inhibitors, proton pump inhibitors, systemic adrenergic blockers, nitrates, calcium channel blockers, hormone replacement therapy) (self-report and confirmed on-site at screening visit)
• Psychological or social characteristic that would interfere with their ability to fully participate in the study (i.e. taking longer than allowed time to complete cognitive assessments)