Exercise Training Intensity and Nitrate Supplementation in Post-Menopausal Females
ConditionMenopause
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexFemale
Age45-75
SponsorUniversity of Virginia
About this trial
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.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Post-menopausal female (greater than age 45 but less than age 75)
Sedentary (does not exercise regularly or less than 2 bouts of exercise per week)
No major changes in medication in the last 3 months
Disqualifiers
Smokers within last 5 years
Weight unstable (loss/gain of more than 3kg in the past 3 months)
Any medical condition that prevents the subject from exercising safely
Hormone replacement therapy (current or within last 3 months)
Trial design
Design model
Parallel
Treatments tested in this trial
Nitrate-Rich Beetroot Juice
Dietary supplementsubjects will consume 1 bottle of nitrate-rich beetroot juice (\~400mg of nitrate each) 2x a day
High Intensity Exercise
Behavioralexercise at an intensity midway between the lactate threshold and VO2peak, from the screening test at an RPE of \~ 15-17
Moderate Intensity Exercise
Behavioralexercise at the RPE at LT associated an \~ RPE of 10-12
Nitrate-Depleted Placebo Beetroot Juice
Dietary supplementSubjects will consume 1 bottle of nitrate-depleted beetroot juice 2x a day
Treatment groups
40 Participants
are divided into 4 treatment groupsGroup A: Nitrate-Rich Beetroot Juice + High Intensity Exercise (HIE)Experimental treatment 2 interventions
Group B: Nitrate-Depleted Placebo Beetroot Juice + High Intensity Exercise (HIE)Placebo comparator 2 interventions
Group C: Nitrate-Rich Beetroot Juice + Moderate Intensity Exercise (MIE)Active comparator 2 interventions
Group D: Nitrate-Depleted Placebo Beetroot Juice + Moderate Intensity Exercise (MIE)Placebo comparator 2 interventions
Trial outcomes
Primary outcomes
1
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.
Time frame
Baseline and after 1-month of exercise training2
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.
Time frame
Baseline and after 1-month of exercise trainingSecondary outcomes
1
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.
Time frame
Baseline and after 1-month of exercise training2
Skeletal muscle perfusion
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.
Time frame
Baseline and after 1-month of exercise training3
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).
Time frame
Baseline and after 1-month of exercise training4
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.
Time frame
Baseline and after 1-month of exercise trainingSponsors and contacts
Click on the lead sponsor to view all of their trials.
Source ClinicalTrials.gov