Short bursts of low oxygen may boost brain circulation

NCT ID NCT05164705

What the study statuses mean

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Recruitment status, easiest to join first

Recruiting now
This trial is taking on new participants right now.
Not yet recruiting
Registered, but not yet taking participants.
By invitation only
Not open to general applications. Only people the study team invites can take part.
Paused
Paused for now. It may or may not start again.
Ongoing
Running, but no longer taking on new participants.
Completed This study
The trial has finished. Results may not be published yet.
Stopped early
Stopped early, before it reached the end. That can be for many reasons, including safety.
Cancelled
Cancelled before anyone took part.

Expanded access (not trials)

Expanded access
Not a trial. This treatment can be requested outside a study, case by case, for people who qualify.
Expanded access (paused)
Not a trial. The treatment can normally be requested outside a study, but is unavailable right now.
Expanded access (ended)
Not a trial. The treatment could once be requested outside a study, but no longer can.
Approved
The treatment has been approved, so it is available normally rather than through this programme.

When the status isn't known

Details not published
The full record has not been published yet, so there is little to show here.
Status unknown
This status has not been confirmed recently, so it may be out of date.

First seen Jul 20, 2026 · Last updated Jul 21, 2026 · Updated 1 time

Summary

This study tests whether 3 weeks of repeated short sessions of low-oxygen breathing can improve blood flow to the brain in healthy adults aged 21 to 50. Participants wear a face mask and alternate between breathing a low-oxygen mixture and normal air for 30 minutes per session. Researchers use MRI scans to measure changes in brain blood flow and how well blood vessels respond to challenges.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

Active substance
Acute Intermittent Hypoxia (brief low-oxygen breathing cycles)
What this could lead to
If it works, this could point toward a non-drug method to boost brain blood flow, potentially helping prevent or treat conditions linked to poor circulation.
What could go wrong
This is a small, early-phase study in healthy adults, so results may not apply to people with medical conditions. The breathing protocol may cause discomfort or dizziness.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Not a phased trial

Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.

Participants

33 people

The number who actually took part.

Started

May 2022

Finished

Apr 2024

Lead sponsor

Other sponsor

The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

21 to 50 years

Sex

Anyone

Healthy volunteers

Accepted

You do not need to have the condition being studied to take part.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Healthy volunteers between ages of 21 and 50 years * No known neurological, respiratory or vascular conditions * Safe to be scanned using MRI * Able to communicate in English Exclusion Criteria: * MRI contraindications as indicated on MRI safety screening form * Subjects with pacemakers, cochlear (in the ear) implants, or aneurysm clips or subjects who have worked with metal * Pregnant women * Individuals with known neurological or vascular conditions * Individuals with sleep apnea, emphysema, or other respiratory conditions * Individuals with severe claustrophobia * Subjects unwilling or unable to give written informed consent in English * Prisoners * Frequent smoker * Allergy to Tegaderm * Blood pressure greater than 140/90 or less than 90/55. * Individuals who report headaches, feeling dizzy or light-headed, or have heart palpitations on the day of the study. * Individuals prescribed Aripiprazole and/or Lamotrigine\* Note, mild (well-controlled) asthma is not immediate grounds for exclusion. \*Other prescription medications may be grounds for exclusion; prescription medication information will be acquired during initial screening and at subsequent follow-up visits

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As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Locations

  • Northwestern University

    Chicago, Illinois, 60611, United States