Aging, Obesity, Postmenopause
Conditions
Keywords
Beetroot juice, Postmenopause, Exercise training, Endothelial function
Brief summary
This study seeks to determine the feasibility of an exercise training progression with the consumption of beetroot juice prior to exercise in postmenopausal women. Results from this investigation will be used to determine preliminary effect sizes for exercise training only (control) and exercise training + beetroot juice (EX+BR) to inform the direction of larger randomized clinical trials on pre-post changes in measures of cardiovascular health and endothelial function.
Detailed description
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.
Interventions
DIETARY_SUPPLEMENTBeetroot Juice
Participants randomly assigned to the EX + BR group will consume 140 mL beetroot juice containing approximately 12 mmol of nitrate 3 hours prior to the supervised exercise training component.
OTHERExercise Training
Participants will perform 8 weeks of supervised exercise training at a frequency of 3x per week.
Sponsors
IU Health University Hospital
Indiana CTSI Clinical Research Center
Bloomington Crossfit
Indiana University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
SINGLE (Subject)
Masking description
Group allocation will be determined at random using a computer-based number in blocks of 2 to ensure equal between-group distribution (i.e. n = 2 Ex only; n = 2 BR+EX). Each number will be kept in a sealed envelope until completion of Visits 1-2.
Intervention model description
Participants will be enrolled in small (n = 4) cohorts or waves to facilitate social support and adherence to the supervised exercise training sessions. We anticipate having 9 waves to successfully reach our target n. This assumes that each wave will have 4 participants, hence, 4 participants x 9 waves = 36 total participants. Subsequently, participants will be randomly selected to: 1) control (EX only) or 2) EX + Beetroot Juice.
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 75 Years
Healthy volunteers
Yes
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)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Retention rate | 8 weeks | The number of randomized participants who complete at least 17 (out of 24 possible) exercise training sessions. |
| Adherence to dietary nitrate intervention | 8 weeks | Breath analysis of fractional exhaled nitric oxide concentrations. |
| Perceived difficulty of training sessions | 8 weeks | Participants will report the perceived exertion at the end of exercise sessions using the Borg category ratio-10 scale that ranges from 0 no exertion to 10 maximal exertion. |
| Recruitment rate | 24 months | The number of eligible participants randomized per months of recruitment time. |
| Adherence to exercise training intervention | 8 weeks | The percent of exercise sessions attended out of the 24 possible sessions. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Soluble endothelial microparticles | Baseline, post-intervention | Blood samples will be analyzed for adhesion molecules (sICAM-1, sVCAM-1, sE-selectin). |
| Distance covered during a six-minute walk test | Baseline, post-intervention | Participants will be asked to walk as far as possible at a preferred speed for six minutes according to ATS standards. Distance covered will be measured in meters. |
Countries
United States
Outcome results
None listed