NCT07238465 · University of Colorado, Denver
Exploring Sympathetic Nervous System Function in Individuals With Down Syndrome
(DIVE)
What this study is about
Down syndrome (DS), the most common genetic cause of intellectual disability, is associated with widespread organ dysfunction, including abnormalities in the autonomic nervous system (ANS). The ANS regulates critical functions such as heart rate (HR) and blood pressure (BP), both essential for maintaining homeostasis and supporting physical activity.
View original scientific description
Down syndrome (DS), the most common genetic cause of intellectual disability, is associated with widespread organ dysfunction, including abnormalities in the autonomic nervous system (ANS). The ANS regulates critical functions such as heart rate (HR) and blood pressure (BP), both essential for maintaining homeostasis and supporting physical activity. Individuals with DS often exhibit blunted HR responses to exercise-typically \~30 beats per minute below expected levels-suggesting reduced sympathetic nervous system (SNS) activity. The SNS governs rapid changes in HR and BP during stress by releasing catecholamines: epinephrine (from the adrenal medulla) and norepinephrine (from sympathetic nerve endings). Despite its importance, SNS function has not been comprehensively assessed among individuals with DS. This study addresses a critical knowledge gap by evaluating SNS responses to physiological stressors in individuals with DS. The investigators will measure beat-to-beat HR and BP, along with plasma catecholamine levels, in response to sympathetic activation, comparing individuals with DS to age- and sex-matched controls. Understanding the mechanisms of SNS dysfunction in DS is vital, as it likely underlies reduced exercise capacity and contributes to broader clinical challenges. These insights may guide targeted interventions to improve cardiovascular function, physical capacity, and overall quality of life in this understudied population.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 18-50 yrs old and apparently healthy individuals
- Ability to understand the study and give assent to participate
- Has a study partner who can attend all visits for the individuals with DS, and answer questionnaires, provide consent when necessary
- Corrected or non-existent congenital heart disease
- Euthyroid or on stable thyroid medication dose for at least 6 months
- Free from cardiovascular, pulmonary, inflammatory, or metabolic disease in the past 6 months that would prevent participation in study procedures
- BMI \<45kg/m2
- Ability to tolerate repeated blood draws / catheter placement
Exclusion criteria
- Hypertension (resting systolic blood pressure \[SBP\] ≥140 and/or diastolic blood pressure \[DBP\] ≥90 mmHg) this includes those on medications to treat hypertension
- Hypotension (resting BP of \<90/60 mmHg)
- Cancer in the last six months
- Any heart-rate-altering medications or any other medication that may modify metabolic responses
- Self-reported diabetes or use of glucose-lowering medication
- Tobacco products, including vaping, or marijuana use
- Currently pregnant
- Post-menopausal women Specific Exclusion Criteria for Certain Stressors:
- Orthopedic limitations that would prohibit exercise or movement for exercise
- Fracture of limb to be immersed for CPT
- Open cut or sore on hand to be immersed for CPT
- Raynaud's syndrome for CPT
- Chronic caffeine drinkers for caffeine stressor (consumption of caffeine in the last 7 days)
Where
- Aurora, Colorado
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 4, 2026 · Source of record for eligibility and locations