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Menopause greatly increases cardiovascular disease risk (CVD). Current exercise guidelines are inadequate to ameliorate this risk and higher intensity exercise may be necessary for cardiovascular benefits in postmenopausal females. Oral nitrate supplementation enhances exercise performance and CVD risk profile in several clinical conditions. The investigators recently reported that 3-days of nitrate supplementation in postmenopausal females enhances acute post-exercise vascular function, in an intensity dependent manner. The effects of nitrate supplementation and exercise training over a longer training program remains unexplored. This investigation will examine the impact of exercise training intensity with and without inorganic nitrate supplementation, on CVD and fitness outcomes. Postmenopausal females will be tested for maximal oxygen uptake and lactate threshold before randomization to one of four groups: that inorganic nitrate-rich beetroot juice, or beetroot juice with nitrate extracted; and assigned to one-month of calorie matched high-intensity or moderate-intensity exercise training. Vascular function and fitness will be evaluated before and after training.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Nitrate-Rich Beetroot Juice + High Intensity Exercise (HIE) | Experimental | Participants assigned to this group will be instructed to consume 1 bottle of nitrate-rich beetroot juice (~400mg of nitrate each) 2x a day (morning a night) starting 2-hours before the first exercise session. Participants will complete a supervised bout of exercise on a treadmill 3x a week for 1-month. Participants will exercise at an RPE of 15-17 based on the participant's VO2peak test. |
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| Nitrate-Depleted Placebo Beetroot Juice + High Intensity Exercise (HIE) | Placebo Comparator | Participants assigned to this group will be instructed to consume 1 bottle of nitrate-depleted beetroot juice 2x a day (morning a night) starting 2-hours before the first exercise session. Participants will complete a supervised bout of exercise on a treadmill 3x a week for 1-month. Participants will exercise at an RPE of 15-17 based on the participant's VO2peak test. |
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| Nitrate-Rich Beetroot Juice + Moderate Intensity Exercise (MIE) | Active Comparator | Participants assigned to this group will be instructed to consume 1 bottle of nitrate-rich beetroot juice (~400mg of nitrate each) 2x a day (morning a night) starting 2-hours before the first exercise session. Participants will complete a supervised bout of exercise on a treadmill 3x a week for 1-month. Participants will exercise at an RPE of 10-12 based on the participant's VO2peak test. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Nitrate-Rich Beetroot Juice | Dietary Supplement | subjects will consume 1 bottle of nitrate-rich beetroot juice (~400mg of nitrate each) 2x a day |
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| Measure | Description | Time Frame |
|---|---|---|
| Vascular Endothelial Function (Flow-Mediated Dilation [FMD]) | Participants will be placed in a supine position with their left forearm slightly extended and supinated with legs straight. The arteries will be imaged using a high-resolution 7.5MHz linear array transducer at rest, during 5 minutes of forearm occlusion via cuff inflation, and continuously for 3 minutes post-occlusion; an EKG trigger will be used to capture images during end-diastole of the cardiac cycle. | Baseline and after 1-month of exercise training |
| Cardiorespiratory Fitness | Peak aerobic capacity (VO2peak) will be assessed using a symptom-limited graded exercise test on a treadmill. An IV will be placed and lactate measured during rest and after the completion of every 3-minute stage to determine lactate threshold at VO2peak. | Baseline and after 1-month of exercise training |
| Measure | Description | Time Frame |
|---|---|---|
| Oral Nitrate Reducing Capacity | Assessment of the oral microbiome's ability to reduce nitrate to nitrite. This will be measured through an unstimulated saliva sample and a rinse of a standard nitrate solution. | Baseline and after 1-month of exercise training |
| Skeletal muscle perfusion |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Casey Derella, PhD | Contact | 434-924-1655 | bxg7vn@uvahealth.org |
| Name | Affiliation | Role |
|---|---|---|
| Jason Allen, PhD | UVA | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Student Health and Wellness Building - Department of Kinesiology | Recruiting | Charlottesville | Virginia | 22903 | United States |
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| ID | Term |
|---|---|
| D000072696 | High-Intensity Interval Training |
| ID | Term |
|---|---|
| D064797 | Physical Conditioning, Human |
| D015444 | Exercise |
| D009043 | Motor Activity |
| D009068 | Movement |
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Subjects will be randomized to one-month of either high or moderate aerobic exercise training and then further randomized to nitrate or placebo.
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A study team member not associated with the trial will perform the randomization scheme for the supplementation. Exercise groups will not be blinded but data will not be analyzed until the end or re-labeled by another team member so assessors are unaware while analyzing the data.
| Nitrate-Depleted Placebo Beetroot Juice + Moderate Intensity Exercise (MIE) |
| Placebo Comparator |
Participants assigned to this group will be instructed to consume 1 bottle of nitrate-depleted beetroot juice 2x a day (morning a night) starting 2-hours before the first exercise session. Participants will complete a supervised bout of exercise on a treadmill 3x a week for 1-month. Participants will exercise at an RPE of 10-12 based on the participant's VO2peak test. |
|
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| High Intensity Exercise | Behavioral | exercise at an intensity midway between the lactate threshold and VO2peak, from the screening test at an RPE of ~ 15-17 |
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| Moderate Intensity Exercise | Behavioral | exercise at the RPE at LT associated an ~ RPE of 10-12 |
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| Nitrate-Depleted Placebo Beetroot Juice | Dietary Supplement | Subjects will consume 1 bottle of nitrate-depleted beetroot juice 2x a day |
|
Skeletal Muscle Blood Flow (straight gauge plethysmography) will be measured non-invasively using venous occlusion/strain-gauge plethysmography both at rest and during reactive hyperemia following 5-minutes of occlusion via the Hokanson A16. A strain gauge device will be place around the widest part of the participant's right calf. A blood pressure place around participant's ankle will be inflated for 60 seconds to eliminate foot circulation from the measurement. At the same time, a cuff placed on the thigh will be inflated to block venous blood flow. The cuff occlusion will be held for ~60 seconds ((several cardiac cycles (4-6 cycles)) to obtain resting blood flow measurements. |
| Baseline and after 1-month of exercise training |
| Peripheral and Central Blood Pressures | Brachial artery blood pressures will be obtained using a standard sphygmomanometer. Aortic blood pressures will be obtained using applanation tonometry (SphygmoCor version 8.0, AtCor Medical). | Baseline and after 1-month of exercise training |
| 24-hour ambulatory blood pressure | Blood pressure will be monitored using a standard ambulatory brachial artery blood pressure cuff (SunTech Oscar 2, SunTech Medical). Blood pressure measurements are programmed to be taken every 30-minutes during the day and every hour at night. This allows for monitoring of nighttime blood pressure changes and variations throughout the day. | Baseline and after 1-month of exercise training |
| Skeletal muscle microvascular perfusion (near-infra-red- spectroscopy) | Tissue oxygenation will be captured noninvasively using non-invasive, near-infrared spectrometry (NIRS, PortaMon, Artinis Medical Systems B.V., The Netherlands) positioned on the gastrocnemius or vastus lateralis muscle. | Baseline and after 1-month of exercise training |
| Lipids | A blood sample will be obtained to measure lipids. | Baseline |
| Hemoglobin | A blood sample will be obtained to measure hemoglobin. | Baseline and after 1-month of exercise training |
| Plasma Nitrate | A fasting blood draw will be taken. Following the blood draw, the participant will take one dose of Beetroot juice. The participant will then return to the lab three hours later for a second blood draw to assess level of nitrate in the plasma. | Baseline and after 1-month of exercise training |
| Plasma Nitrite | A fasting blood draw will be taken. Following the blood draw, the participant will take one dose of Beetroot juice. The participant will then return to the lab three hours later for a second blood draw to assess level of nitrite in the plasma. | Baseline and after 1-month of exercise training |
| D009142 |
| Musculoskeletal Physiological Phenomena |
| D055687 | Musculoskeletal and Neural Physiological Phenomena |