Low-intensity Resistance Exercise and Diet on Arterial Function and Blood Pressure
Condition: Obesity; Pre-hypertension; Hypertension
MeSH terms: Hypertension; Prehypertension
Study type: Interventional

Summary: 
      -  Obesity is a major risk factor for premature arterial abnormalities including high blood
           pressure and increased stiffness. Previous studies have shown that weight loss via
           lifestyle modifications is associated with a decrease in large artery (aorta) stiffness.
           However, along with decreases in fat mass, hypocaloric diet reduces muscle mass.
           Low-intensity resistance exercise training (LIRET) results in similar increases in
           muscle mass and strength than those observed after high-intensity resistance exercise.

        -  The investigators hypothesis is that weight loss via diet combined with LIRET would
           additively reduce arterial stiffness and blood pressure (BP) in obese women. The
           investigators also hypothesize that the improved arterial function with weight loss
           would be associated with beneficial changes in the main mechanisms involved in BP
           regulation.
    

Detailed description: 
      The purpose of the study is to examine the effects of 12 weeks of low-intensity resistance
      exercise training (LIRET) and diet on arterial function, autonomic function, and body
      composition in obese women with high blood pressure (BP). Specific aims of the study are to:

        -  To evaluate the extent to which diet and LIRET will improve body composition assessed by
           changes in fat mass and lean mass using dual-energy x-ray absorptiometry and waist
           circumference.

        -  To investigate that combined diet and LIRET are more efficacious than either treatment
           alone in ameliorating cardiovascular disease risk factors by assessing arterial
           stiffness (aortic, systemic, and leg), aortic BP and wave reflection, and autonomic
           function (heart rate variability, vascular sympathetic activity [low-frequency power of
           systolic BP variability], and baroreflex sensitivity). Circulating levels of
           adipocytokines (adiponectin and leptin) and endothelial-derived vasodilators (NO
           metabolites [NOx] and prostacyclin) and vasoconstrictors (endothelin-1 and prostaglandin
           F2α) will be assessed as secondary outcome variables.
    

Intervention name(s): Resistance exercise training; Hypocaloric diet; Resistance exercise training & diet
Intervention type(s): Other; Other; Other
Intervention description(s): The low intensity resistance exercise training intervention consists of lower-body resistance exercise (machines) 3 times per wk for 12 wk. Two sets the first 2 wk and 3 sets the rest of the intervention, at 40% of the estimated 1 repetition maximum, for 17 to 23 repetitions, with 1 minute of rest in between sets.; The hypocaloric diet intervention consists of 12 wk of the standard Nutrisystem foods plan complemented by fresh produce and dairy. Subjects consume breakfast, lunch, dinner, and one (women) or two (men) snacks per day.; Combination of low intensity resistance exercise training and hypocaloric diet
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Investigator)
Primary purpose: Basic Science
Keywords: low intensity resistance exercise training; hypocaloric diet; prehypertension; hypertension; obesity; arterial function; arterial stiffness; pulse wave velocity; autonomic function; endothelial function; adipocytokines