Taking people in United StatesPhase 3

How the body's stress response works in adults with Down syndrome

Studies nervous system responses to stress tests in adults with Down syndrome.

Key facts

Who runs it: University of Colorado, Denver
Where: Aurora, United StatesSee the site
Trial code: NCT07238465
Registry title: Exploring Sympathetic Nervous System Function in Individuals With Down Syndrome
Status: Recruiting
Phase: Phase 3
People taking part: 200 people, planned
Started: 6 Apr 2026
Expected to end: Dec 2030
Type of study: Interventional, 2 groups
Treatments tested: Cold Stress
Maximal Dynamic Exercise
Isometric Handgrip Exercise with Post-Exercise Muscle Ischemia
Head-up Tilt Table Test
Record updated: 13 October 2026

Who can take part

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for adults with Down syndrome and adults without Down syndrome of the same age and sex. It studies how the body's stress nerve system controls heart rate and blood pressure.

Age: 18 to 50 years
Sex: All sexes
Disease stage: People with Down syndrome, and people without it as a comparison group. All must be otherwise healthy. Any heart defect present from birth must have been repaired, or there must be none. No heart, lung, inflammatory or metabolic disease in the past 6 months that would stop them doing the study tests. Normal thyroid function, or a stable thyroid medicine dose for at least 6 months. BMI <45kg/m2.
Earlier treatment: People cannot join if they take medicines that change heart rate or metabolism, blood pressure medicines, or sugar-lowering medicines.

Main reasons for not taking part

High blood pressure (140/90 mmHg or more) or low blood pressure (below 90/60 mmHg)
Cancer in the last six months
Diabetes
Using tobacco, vaping or marijuana
Being pregnant now or after menopause

The registry criteria, word for word

Show all 20 criteriaShow less

Who can take part

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

Who cannot take part

Hypertension (resting systolic blood pressure [SBP] ≥140 and/or diastolic blood pressure [DBP] ≥90 mmHg) this includes those on medications to treat hypertension
Cancer in the last six months
Any heart-rate-altering medications or any other medication that may modify metabolic responses
Raynaud's syndrome for CPT
Self-reported diabetes or use of glucose-lowering medication
Hypotension (resting BP of <90/60 mmHg)
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

Check if you might fit

Answer for yourself. This is not a decision: only the study team can say whether you can take part.

Are you between 18 and 50 years old?

Where in United States

Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical CampusAurora, United StatesContact: Joaquin M Espinosa, PhDTaking people

About the trial

What the trial wants to find out

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.

Read full original descriptionShow less

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.

The 2 groups in the trial

Individuals with Down syndromeTreatment being tested
The investigators will be recruiting participants between the ages of 18-50 for the study investigating responses to four sympathetic stressors compared to age and sex matched individuals without Down syndrome.
Treatment: Cold Stress, Maximal Dynamic Exercise, Isometric Handgrip Exercise with Post-Exercise Muscle Ischemia, and Head-up Tilt Table Test
Individuals without Down syndromeTreatment being tested
The investigators will be recruiting individuals without Down syndrome between the ages of 18-50 to serve as the comparisons for individuals with Down syndrome across the four sympathetic stressors.
Treatment: Cold Stress, Maximal Dynamic Exercise, Isometric Handgrip Exercise with Post-Exercise Muscle Ischemia, and Head-up Tilt Table Test