An interventional study of Moderate Intensity Aerobic Exercise in Post-Exercise Hypotension, sponsored by University of Delaware. Recruiting at 1 site in United States. Open to participants aged 18 Years to 45 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2023-11-28.
Sponsored by University of Delaware · Not applicable, Interventional, and Basic science
The goal of this study is to learn about how blood vessel dilation after exercise effects pulse wave reflection and influences the function of the heart in healthy young adults. The main question it aims to answer is: Are post-exercise decreases in reflected pulse waves due to a decrease in the stiffness of large arteries in the leg or an increase in leg blood flow? Participants will exercise on a stationary bicycle at a moderate intensity for 1 hour during two laboratory visits. Participants will take oral antihistamines to block post-exercise dilation at one visit, and they will take placebo pills at the other visit. At both visits, leg blood flow, pulse wave velocity, and heart function will be measured before exercise and for 120-minutes after exercise.
During exercise, blood vessels increase in size to supply muscles with more blood. After exercise, the muscles that had been used release chemicals called histamines that cause the blood vessels to stay dilated even when the muscles no longer need more blood. It takes around 2 hours for the blood vessels to return to normal. This causes blood pressure to be lower than it usually is at rest. This phenomenon delays the return of pressure waves in arteries that are reflected back to the heart resulting in the heart having to work less hard to pump out blood for about 2 hours after exercise. However, it is unknown why the reflected pressure waves return to the heart later. The aim of this study is to determine if this delay is due to the speed of the reflected waves being slowed by large arteries or dilation of small arteries resulting in the reflections originating further from the heart. By giving antihistamines prior to exercise, post-exercise blood vessel dilation of the small arteries will be largely reduced, thus allowing for the determination of which factor causes the reflected waves to return later. Additionally, it is hypothesized that the reduction in work that the heart must perform results in improved contraction and relaxation of the heart. Thus, an additional aim is to determine how post-exercise blood vessel dilation influence heart function.
To accomplish these aims, blood flow leaving the left ventricle and femoral blood flow will be measured via Doppler ultrasound. Applanation tonometry will be used to record pulse waves at the carotid, radial, femoral, and dorsalis pedis arteries. These pulse waves will be used to estimate central blood pressure and to determine pulse wave velocity of different arterial segments. Measurements will be made at baseline and for 120 minutes after a bout of moderate intensity aerobic exercise.
22 studies on the registry are indexed under Post-Exercise Hypotension; 2 are open to participants now.
This study's planned enrollment of 25 is above the median of 21 across 22 interventional studies indexed under Post-Exercise Hypotension.
Browse Post-Exercise Hypotension studies →University of Delaware is the lead sponsor of 128 studies on the registry; 22 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The oral antihistamine condition will consist of fexofenadine (540mg) and famotidine (40mg). Commercially available pills (3 x 180mg fexofenadine and 2 x 20mg famotidine) will be placed within opaque capsules and administered to the participants upon arrival to the laboratory.
Other: Moderate Intensity Aerobic Exercise
The placebo condition will consist of dextrose in an identical number of opaque capsules as the antihistamine treatment. Total dextrose will be \<5g. The capsules will be administered to the participants upon arrival to the laboratory.
Other: Moderate Intensity Aerobic Exercise
Participants will complete 1 hour of exercise on a cycle ergometer at the power output that elicits 60% of their peak rate of oxygen consumption (V02peak).
Change in lower limb arterial stiffness
Arterial stiffness of the leg will be assessed via measurement of femoral-pedis pulse wave velocity.
Time frame: 120 minutes post-exercise
Change in leg vascular conductance
Vascular conductance, an index of peripheral vasodilation, will be determined by measuring femoral blood flow via ultrasound and dividing by mean arterial pressure.
Time frame: 120 minutes post-exercise
Change in left ventricular pulsatile load
Doppler echocardiography and arterial tonometry will be used to establish left ventricular pressure-flow relations. Wave separation analysis will subsequently be performed to determine the magnitude and timing of reflected pulse waves.
Time frame: 120 post-exercise
Change in left ventricular diastolic function
Echocardiographic measures of left ventricular diastolic function will be recorded, including mitral annulus tissue velocity and mitral in-flow velocity
Time frame: 120 minutes post-exercise
Plan to share: Undecided
No publications or documents are linked to this record.
Started May 2023 (actual). Primary completion is estimated for Apr 2024, 11 months after the start.
Of 14 interventional studies with no phase under Post-Exercise Hypotension, half reached primary completion within 13 months of starting (the median), counting those still running; a quarter within 9 and three quarters within 15. This study's planned 11 months is below that.
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