8 Weeks of L-CIT Supplementation and LIRET on Vascular Function in Hypertensive Postmenopausal Women
Condition: Hypertension; Menopause
MeSH terms: Hypertension
Study type: Interventional

Summary: 
      The overall objective of this project is to bring forth evidence that L-Citrulline (L-CIT)
      supplementation and low intensity resistance exercise training (LIRET) alone and combined
      will improve vascular function and muscle fitness (mass, strength, and exercise performance)
      in postmenopausal women with hypertension. The investigators' central hypothesis is that
      adjuvant L-CIT supplementation may synergistically enhance vascular (arterial stiffness, BP,
      muscle oxygenation, blood flow) and muscular (strength, exercise performance) responses to
      LIRET in postmenopausal women with hypertension by improving endothelial vasodilatory
      function.
    

Detailed description: 
      Individuals who are on medications will refrain from use the morning of all laboratory
      visits. Participants will be asked to bring medications with them, and will be allowed to
      ingest it after the vascular measurements have been obtained.

      There will be a total of 7 laboratory visits. The 1st visit will be approximately 1 hr and 45
      minutes. The 2nd and 3rd visit will be approximately 2 hrs. The 4th and 6th visit will total
      about 2 hrs and 15 minutes and finally, the 5th and 7th visit will total about 1hr and 15
      minutes. This means the total participant time for laboratory visits will be approximately 12
      hours. In addition to this, the second 4 weeks of the 8 week study period will involve coming
      to the Kinesiology and Sport Management building at Texas Tech University main campus 3 times
      per week to perform the low-intensity resistance training intervention. These visits should
      last no more than 30-45 minutes.

      The first 3 visits will be separated by 48-72 hrs. Visits 3 and 4 will be separated by 4
      weeks (first 4 weeks of LCIT or Placebo supplementation). Visits 4 and 5 will be separated by
      48-72 hours. Visits 5 and 6 will again be separated by 4 weeks (Second 4 weeks of LCIT or
      Placebo supplementation with the addition of Low-intensity resistance exercise in both
      groups).

      Approximately 12 hours total for each of the 7 laboratory visits, as well as 30-45 minutes 3
      times per week during the last 4 weeks of the 8 week study.

      Using a parallel placebo-controlled design, postmenopausal women with elevated blood pressure
      or hypertension will be randomized to receive L-CIT supplementation (10g/day) alone for 4
      weeks, followed by 4 weeks of L-CIT supplementation in combination with low-intensity
      resistance training or placebo (maltodextrin) alone for 4 weeks, followed by 4 weeks of
      placebo in combination with low-intensity resistance training.

      Differences between conditions (Citrulline vs Placebo) will be analyzed with independent
      samples t-test. Two-way ANOVA with repeated measures with Bonferroni adjustments will be used
      to analyze group (CIT vs. PL) by time (baseline, post-supplementation only, supplement +
      low-intensity resistance exercise training) interactions between the outcome variables. If
      group-by-time interactions are detected, post-hoc comparisons will be performed via paired or
      independent t-tests.
    

Intervention name(s): L-Citrulline; Placebo
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): 8 weeks of L-Citrulline supplementation (10 grams/day); 8 weeks of Placebo (maltodextrin; 10 grams/day)
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Double-blind (subject, investigator), randomized, parallel, placebo-controlled
Masking: Double (Participant, Investigator)
Primary purpose: Basic Science
Keywords: Endothelial Function; Arterial Stiffness; Muscle Function