Low-intensity Resistance Exercise and Diet on Arterial Function and Blood Pressure

Effects of Low-intensity Resistance Exercise Training and Diet on Central Hemodynamics and Arterial Stiffness in Obese Middle-aged Women With High Blood Pressure

• 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.

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.

Inclusion Criteria:

• Female
• 40 to 65 years of age
• Body mass index of 27-39.9
• Sedentary or low active (less than 2 hr per wk)

Exclusion Criteria:

• Younger than 40 or older than 65 years of age
• Body mass index lower than 27, or 40 or higher
• Physically active or competitively active
• Smoker
• Systolic blood pressure higher than 140 mmHg
• Use of hormone replacement therapy of less than 1 yr
• Use of calcium channel blocker or beta blockers
• Type 1 diabetes
• Uncontrolled type 2 diabetes