Traditional medical treatments are often based on research done exclusively in males, and recent research efforts in the physiology community have highlighted critical sex differences in disease presentation and progression. For example, the relative risk of fatal heart disease is 50% greater in obese, diabetic women as compared to their male counterparts, and women appear to respond differently to lifestyle interventions such as exercise compared with men. Chronic passive heat exposure (hot tub use) provides alternative or supplemental therapeutic potential for improving cardiovascular and metabolic health in obese women. In addition, passive heat exposure may offer specific cellular protection from stresses like a lack of blood flow (ischemia), which is the primary cause of fatal coronary heart disease. This study is investigating the possible cardiovascular and metabolic health benefits of chronic passive heat exposure, and whether regular hot tub use (3-4 days per week for 8-10 weeks) may reduce obese womens' cardiometabolic risk. The investigators are examining cardiovascular health through blood pressure, blood vessel stiffness, sympathetic ('fight or flight') activity, and responsiveness to stresses like increased or decreased blood flow. The investigators are also examining metabolic health through an oral glucose tolerance test and a subcutaneous fat biopsy. The goal of this research is to develop a therapy targeted toward the specific health needs and complications of obese women, in an effort to improve cardiovascular and metabolic health and provide therapeutic alternatives in this high-risk population.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Enrollment
20
Regular hot tub use
University of Oregon
Eugene, Oregon, United States
systolic blood pressure
Resting supine blood pressure, measured in triplicate with median recorded
Time frame: through study completion, an average of 10 weeks
diastolic blood pressure
Resting supine blood pressure, measured in triplicate with median recorded
Time frame: through study completion, an average of 10 weeks
oral glucose tolerance test
glucose and insulin responses to a 75-g, 2-hr oral glucose tolerance test after a 12+hr fast
Time frame: through study completion, an average of 10 weeks
muscle sympathetic nerve activity burst frequency
recording of sympathetic nerve traffic during supine rest, quantified as burst count per minute
Time frame: through study completion, an average of 10 weeks
arterial wall thickness (carotid)
intimal thickness of common carotid artery assessed using doppler ultrasonography
Time frame: through study completion, an average of 10 weeks
arterial wall thickness (femoral)
intimal thickness of superficial femoral artery assessed using doppler ultrasonography
Time frame: through study completion, an average of 10 weeks
dynamic arterial compliance (carotid)
arterial compliance of common carotid artery measured using ultrasonography
Time frame: through study completion, an average of 10 weeks
dynamic arterial compliance (femoral)
arterial compliance of superficial femoral artery measured using ultrasonography
Time frame: through study completion, an average of 10 weeks
flow mediated dilation
flow-mediated dilation of brachial artery, expressed as % change in diameter. A measure of endothelial function.
Time frame: through study completion, an average of 10 weeks
flow mediated dilation after ischemia-reperfusion
flow-mediated dilation of brachial artery, expressed as % change in diameter, following 20 minute ischemia-20 minute reperfusion. A measure of vascular tolerance to ischemia-reperfusion stress.
Time frame: through study completion, an average of 10 weeks
Abdominal subcutaneous fat biopsy
Adipose tissue sample analyzed for insulin signaling, markers of inflammation, and heat shock protein expression
Time frame: through study completion, an average of 10 weeks
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