The purpose of this study is to determine 1) if young adults with metabolic syndrome display endothelial dysfunction of the internal carotid artery in a sex-specific fashion and 2) if this endothelial dysfunction can be acutely improved with a single bout of exercise. This will be achieved by testing internal carotid artery function before and after a 30-minute bout of moderate intensity exercise. 48 young adults with and without metabolic syndrome will be enrolled and will be on study for approximately 5.5 hours over 4 study visits.
The goal of this project is to determine if young MetSyn patients exhibit carotid endothelial dysfunction (ED) in a sex-specific manner and if exercise can acutely restore internal carotid artery (ICA) function. The investigators will test this by first quantifying ICA endothelial function using an inhaled gas stressor (CO2) to acutely increase ICA shear rate (SR) and measuring the vascular responsiveness to this increased SR. Carotid endothelial function has never been tested in this way in patients with MetSyn before. Then, a 30 min bout of cycling exercise will be performed followed by the same gas stressor test to determine if ICA endothelial function can be acutely improved in MetSyn. The aims and hypotheses are to: * Aim 1: Determine if young adults with MetSyn exhibit carotid ED compared to healthy adults. Hypothesis: carotid ED will be present in young adults with MetSyn. * Aim 2: Determine if sex differences exist in carotid endothelial function in MetSyn. Hypothesis: MetSyn will result in greater declines in carotid endothelial function in females. * Aim 3: Determine if exercise yields an acute benefit on carotid endothelial function in young adults with MetSyn. Hypothesis: young adults with MetSyn will receive a greater increase in carotid endothelial function from a single bout of exercise than healthy adults.
Study Type
OBSERVATIONAL
Enrollment
48
30 minute bout of cycling
* Doppler Ultrasound used to non-invasively assess the diameter and blood flow going into an artery, the ICA in this study. * Indirect calorimeter in tandem with semi-recumbent bike used to assess O2 consumption * heart rate monitor
Three gases of different composition are used to ensure that the proper PETCO2 administration desired for this study occurs in tandem with keeping inspired O2 content constant. This is achieved by used a 5% O2, 95% CO2 tank, a 5% O2, 95% N2 tank, and a 100% O2 tank. In tandem, the use of these three tanks allows for precise control of PETCO2 without a change in inspired O2.
University of Wisconsin
Madison, Wisconsin, United States
RECRUITINGAim 1: Baseline ICA cSMD measures assessed by MetSyn versus healthy controls
Internal carotid artery cerebral shear-mediated dilation (cSMD) is measured by doppler ultrasound and reported in percentage increase in diameter. A resting baseline period for 5 minutes breathing room air followed by 30 seconds of breathing CO2-mixed air at +9 mmHg PETCO2 used to evoke an increase in blood flow to the ICA.
Time frame: baseline
Aim 2: Baseline ICA cSMD measures assessed by MetSyn versus sex
Internal carotid artery cerebral shear-mediated dilation is measured by doppler ultrasound and reported in percentage increase in diameter. A resting baseline period for 5 minutes breathing room air followed by 30 seconds of breathing CO2-mixed air at +9 mmHg PETCO2 used to evoke an increase in blood flow to the ICA.
Time frame: baseline
Aim 3: Post-exercise cSMD response by MetSyn versus healthy controls
Internal carotid artery cerebral shear-mediated dilation is measured by doppler ultrasound and reported in percentage increase in diameter. 30 minutes of exercise on a cycle ergometer will be performed at 80% of the ventilatory threshold determined during the graded exercise test.
Time frame: measured during exercise and 10 and 60 minutes post-exercise
Aim 3: Duration of Response to Exercise
Duration of post-exercise improvements will be investigated by testing ICA cSMD 10 min and 60 min post-exercise. 30 minutes of exercise on a cycle ergometer will be performed at 80% of the ventilatory threshold determined during the graded exercise test. For the duration of the exercise, indirect calorimetry will be used to assess VO2 to confirm the target workload of 80% of the ventilatory threshold. During this 30 minutes of exercise, ICA diameter and velocity will be measured using ultrasonography every 5 minutes for a 2-minute period.
Time frame: measured during exercise and 10 and 60 minutes post-exercise
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