How changes in brain blood flow affect breathing during sleep
Official title: Role of Cerebral Blood Flow on Ventilatory Stability During Sleep in Normoxia and Intermittent Hypoxia
Run by University of Calgary · NCT03255408 · Data updated 2026-11-12
This project will test whether temporarily lowering blood flow to the brain changes how healthy adults' breathing responds to low oxygen and high carbon dioxide during normal sleep and short periods of low oxygen.
Quick facts
| Phase | Phase1; Phase2 |
|---|---|
| Study type | Interventional |
| Ages | 18 Years to 45 Years |
| Sex | All |
| Enrollment | 12 (estimated) |
| Sponsor | University of Calgary Academic / other |
| Locations | 1 site (Calgary, Alberta) |
| Status | Recruiting |
| Started | January 1, 2023 |
| Main results expected | December 30, 2027 |
| Study ends | December 30, 2027 |
| Registry record updated | May 1, 2026 |
| Trial ID | NCT03255408 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Healthy adults aged 18–45 living in Calgary for at least one year who are non-smokers, not pregnant or obese, free of major cardiovascular, cerebrovascular, renal, or metabolic disease, not taking blood pressure medications, and not lactose intolerant.
✕Probably not a fit
People with obstructive sleep apnea, obesity, pregnancy, smoking history, major chronic diseases, or those taking blood pressure medications are excluded and unlikely to receive direct benefit from participation.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This randomized, double-blind, placebo-controlled crossover study uses a drug to lower cerebral blood flow and compares ventilatory chemoreflexes before, during, and after sleep under normal oxygen and isocapnic intermittent hypoxia. Participants will sleep under both conditions in random order with washout periods between sessions while investigators measure acute ventilatory responses to hypoxia (AHVR) and hypercapnia (HCVR). Cerebral blood flow will be pharmacologically manipulated in randomized order against placebo, and venous blood and urine samples will be collected for vascular biomarkers. All procedures are performed at a single center (University of Calgary) in healthy adults aged 18–45.
Why it matters
Potential benefit: If successful, findings could clarify how brain blood flow influences breathing control during sleep and guide strategies to protect breathing in people at risk for sleep-disordered breathing or cerebrovascular events.
How similar studies have gone: Prior physiological studies have examined cerebral blood flow and ventilatory chemoreflexes in short-term settings, but combining pharmacological CBF lowering with isocapnic intermittent hypoxia during sleep is relatively novel.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Healthy adults * 18 - 45 years of age * Living in Calgary for the past one year * Have no medical condition or should not be taking any blood pressure medications. * The participant should not be lactose intolerant Exclusion Criteria: * Cerebrovascular, cardio-respiratory, renal and metabolic diseases * Bleeding disorders and upper gastrointestinal diseases e.g. peptic ulcer disease * Pregnancy, obese and sleep-disordered breathing * Drug allergies to non-steroidal anti-inflammatories * Currently smoking
Where it's running
-
University of Calgary
Calgary, Alberta, Canada Recruiting
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.