Diet and Whole-body Vibration Training on Cardiovascular and Autonomic Function
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. Whole body vibration
      results in similar increases in muscle mass and strength than those observed after resistance
      exercise and is feasible for special populations such as the obese and the elderly.

      The investigators hypothesis is that weight loss via diet combined with whole body vibration
      training would additively reduce arterial stiffness and blood pressure 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 whole body vibration
      training (WBVT) and diet on arterial function, autonomic function, and body composition in
      obese women. Specific aims of the study are to:

      To evaluate the extent to which diet and (WBVT) 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 (WBVT) 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). Flow mediated dilation and circulating levels of adipocytokines
      (adiponectin and leptin) and endothelial-derived vasodilators (NO metabolites [NOx], 6-keto
      PGFIa, insulin, and ghrelin) and vasoconstrictors (endothelin-1 [ET-1],8-iso PGF2a,vascular
      endothelium growth factor [VGEF]) will be assessed as secondary outcome variables.
    

Intervention name(s): Whole Body Vibration Training; Hypocaloric diet; Whole body vibration training & diet
Intervention type(s): Other; Other; Other
Intervention description(s): The Whole body vibration training intervention consists of lower-body exercise in a vibration platform 3 times per wk for 12 wk. The subjects will perform static and dynamic exercises for the legs on the vibration platform. Dynamic exercises will be performed with slow controlled movements starting from an upright position into a 60 degree knee flexion (squat) and maximal heel elevation (toestand). Static exercises will be performed without movement in the joint angles described previously. The training volume will increase progressively over the 12-week training period by increasing the intensity of vibration, duration of the exercise set (30-60 sec), number of sets per exercise, and total duration of the training session, and decreasing the duration of rest periods (30-60 sec).The intensity of vibration and amplitude will also be increased progressively (25-30 Hz of frequency and from low to high amplitude).; 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 whole body vibration training and hypocaloric diet
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: whole body vibration training; hypocaloric diet; prehypertension; hypertension; obesity; arterial function; arterial stiffness; pulse wave velocity; autonomic function; endothelial function; adipocytokines