Hypoxia, AltitudeRIVER-AsthmaNCT07431580
Effect of Acute Hypoxia on RIght VEntRicular Function in Asthma.
A study testing Normobaric Hypoxia in people with Hypoxia, Altitude and Hypoxia, run by Mona Lichtblau at 1 site in Switzerland.
Trial summary
More and more people are engaging in sports in the mountains, including individuals with heart or lung diseases. At the same time, such diseases are becoming more common in Switzerland. Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Hypoxia, Altitude, Hypoxia, Normobaric Hypoxia
- What is being tested?
- Normobaric Hypoxia
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 18 participants
- Where
- 1 siteSwitzerland
- Study dates
- 26 May 2026to Jan 2030
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Signed informed consent
- Diagnosed and well controlled asthma bronchiale
- 18-80 years (age group young: 18-39.99 years / age group older: 40-80 years)
- All sex and genders
- Living <800m and without altitude exposure > 2500 m and > 24h within the last three weeks
Who cannot join
- <18, >80 years old
- Any other diagnosed cardiopulmonary condition including past HAPE
- Other clinically significant severe concomitant disease states (e.g. renal, hepatic dysfunction, etc.)
- Inability to follow the procedures of the study due to language problems, psychological neurological disorders or orthopaedic disorders
- Participants permanently living >800m and altitude exposure > 2500 m and >24h within the last three weeks
- Pregnancy: Participants will be asked if pregnant or not, no screening for undetected pregnancy
- Lactating women
- Participation in other study with active treatment
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Switzerland1 site, 1 recruiting
- Recruiting
Consultant Clinic of Pulmonology, University Hospital of Zurich
Zurich, Canton of Zurich, 8091
Mona Lichtblau, PD Dr. med., mona.lichtblau@usz.ch
Carmen Wick, Cand. PhD, +41 43 253 44 05, carmen.wick@usz.ch
About this study
Official title: Effect of Acute Hypoxia on RIght VEntRicular Function. A Single-Center, Double-Blind, Randomized Controlled Cross-Over Trial.
More and more people are engaging in sports in the mountains, including individuals with heart or lung diseases. At the same time, such diseases are becoming more common in Switzerland. At high altitude, less oxygen is available, which places stress on the body-particularly on the heart, which has to pump blood through the lungs. How the heart, especially the right ventricle, in people with asthma responds to this stress is still not well understood.
Therefore, this study investigates how the heart responds to simulated altitudes of 2,500 m and 4,000 m, both at rest and during light physical activity in patients with asthma. The primary objective is to assess how right ventricular function changes under conditions of reduced oxygen availability.
Read more
In addition, vital signs, changes in blood gases, oxygen levels in blood and tissue and shortness of breath are assessed. The "altitude" is simulated using a special gas mixture that participants inhale. Participants undergo three altitude conditions (490, 2,500, and 4,000 m above sea level). The order of the altitude conditions is assigned at random.
The aim is to better understand how the right ventricle and other parameters respond to low-oxygen conditions and how affected patients can be better supported in the future.
Read the detailed description
Outdoor activities in the mountains are becoming increasingly popular. At higher altitudes, the air contains less oxygen, which puts extra strain on the body-especially on the heart. The right side of the heart plays a key role in pumping blood through the lungs and may need to work harder when oxygen levels are low. While the heart's response to long-term altitude exposure is relatively well known, much less is understood about how the heart reacts to short-term (acute) exposure to low oxygen, particularly during light physical activity and in individuals with asthma.
This study aims to better understand how the right ventricle responds to short-term simulated altitude exposure. Participants with asthma will be exposed to different oxygen levels that correspond to altitudes of 490 m (near sea level), 2,500 m, and 4,000 m, both at rest and during light cycling exercise.
The main focus of the study is to measure changes in right ventricular function, assessed using a non-invasive heart ultrasound technique called speckle-tracking echocardiography. In addition, heart rate, blood pressure, oxygen saturation, and symptoms such as shortness of breath and leg fatigue will be recorded.
The study is conducted at a single center and uses a randomized, double-blind, cross-over design, meaning that each participant undergoes all altitude conditions in a random order, and neither the participants nor the investigators know which altitude is being simulated at a given time.
Participants Only adults aged 18-80 years with diagnosed asthma bronchiale will be included. Participants must live below 800 m above sea level and must not have been exposed to higher altitudes for more than 24 hours in the three weeks before participation. Individuals with significant other medical conditions, pregnancy, need for long-term oxygen therapy, or inability to follow the study procedures will be excluded.
Study procedures
Each study visit includes:
- 1 hour resting period
- Measurement of vital signs (heart rate, blood pressure, oxygen saturation)
- Heart ultrasound at rest
- A 10-minute low-intensity cycling exercise
- Repeated heart ultrasound during and symptom assessment after exercise
- Low-oxygen conditions are created using a special gas mixture that participants breathe through a mask. Each condition is separated by at least 2 hours wash-out period to ensure recovery.
Study size and duration Based on statistical calculations, 18 participants will be recruited to allow balanced allocation across all study conditions and to account for potential dropouts. Participation may take place over two to three days, depending on the preferred schedule of the participant. The days can be spread or be spread over several weeks, depending on individual availability.
Aim of the study The goal of this study is to improve understanding of how the right side of the heart responds to short-term low-oxygen exposure at rest and during light exercise. This knowledge will help interpret future findings in patients with heart or lung disease and may contribute to safer recommendations for physical activity at altitude.
- Being tested
- Normobaric Hypoxia
- Keywords
- right ventricular free wall strain, RVFWS, right ventricular function, tissue oxygenation, breathing difficulty, blood gas, heart rate
- Medical subject headings
- Altitude Sickness, Hypoxia, Dyspnea
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Normobaric HypoxiaOther
Also called rest, low intensity cycling, normobaric normoxia
Normobaric hypoxia according to 408m (control/normobaric normoxia), 2500 m and 4000 m above sea-level at rest for 1 hour and at low intensity cycling for 10 minutes (5 min 30 W, 5 min 60 W).
| Study group | Role | What they receive |
|---|---|---|
| Arm ABC (normobaric normoxia - normobaric hypoxia 2500m - normobaric hypoxia 4000m) | Other | The participant receives first normobaric normoxia (A), then normobaric hypoxia equal to 2500 m.a.s.l. (B) then normobaric hypoxia representing 4000 m.a.s.l. (C). Condition A represents the control. Receives: Other: Normobaric Hypoxia |
| Arm ACB (normobaric normoxia - normobaric hypoxia 4000m - normobaric hypoxia 2500m) | Other | The participant receives first normobaric normoxia (A), then normobaric hypoxia representing 4000 m.a.s.l. (C), then normobaric hypoxia equal to 2500 m.a.s.l. (B). Condition A represents the control. Receives: Other: Normobaric Hypoxia |
| Arm BAC (normobaric hypoxia 2500m - normobaric normoxia - normobaric hypoxia 4000m) | Other | The participant receives first normobaric hypoxia equal to 2500 m.a.s.l. (B), then normobaric normoxia (A), then normobaric hypoxia representing 4000 m.a.s.l. (C). Condition A represents the control. Receives: Other: Normobaric Hypoxia |
| Arm BCA (normobaric hypoxia 2500m - normobaric hypoxia 4000m - normobaric normoxia) | Other | The participant receives first normobaric hypoxia equal to 2500 m.a.s.l. (B), then normobaric hypoxia representing 4000 m.a.s.l. (C), then normobaric normoxia (A). Condition A represents the control. Receives: Other: Normobaric Hypoxia |
| Arm CAB (normobaric hypoxia 4000m - normobaric normoxia - normobaric hypoxia 2500m) | Other | The participant receives first normobaric hypoxia representing 4000 m.a.s.l. (C), then normobaric normoxia (A), then normobaric hypoxia equal to 2500 m.a.s.l. (B). Condition A represents the control. Receives: Other: Normobaric Hypoxia |
| Arm CBA (normobaric hypoxia 4000m - normobaric hypoxia 2500m - normobaric normoxia) | Other | The participant receives first normobaric hypoxia representing 4000 m.a.s.l. (C), then normobaric hypoxia equal to 2500 m.a.s.l. (B), then normobaric normoxia (A). Condition A represents the control. Receives: Other: Normobaric Hypoxia |
What is being measured
The primary outcome is the main question the study is designed to answer.
Right ventricular free wall strain
The primary endpoint is defined as the right ventricular free wall strain (RVFWS) from condition normobaric normoxia to condition 4000m for group 1 and from normobaric normoxia to condition 2500m for group 2 at rest. RVFWS will be measured by speckle tracking strain analysis according to the guidelines of the European Association of Cardiology. Speckle tracking echocardiography allows to assess the right ventricular volume and true global RV function without relying on geometric assumption and is a valuable clinical bedside tool for assessing myocardial strain. Tomtec software (Philipps) will be used.
Measured: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
Secondary outcomes (19)
Tricuspid annular plane systolic excursion (TAPSE)
Differences in tricuspid annular plane systolic excursion (TAPSE) [cm] between the conditions at rest and during exercise, measured according to the guidelines of the European Association of cardiology.
Measured: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
Right ventricular-arterial coupling
Differences in TAPSE/sPAP and RVFWS/sPAP between the conditions at rest and during exercise, measured by echocardiography, as a validated, noninvasive measure of right ventricular-arterial coupling.
Measured: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
RV/PA
Differences in RV/PA ratio between the conditions at rest and during exercise, measured by echocardiography according to the guidelines of the European Association of cardiology.
Measured: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
Stroke volume
Differences in stroke volume based on the left ventricular outflow tract diameter and the velocity time integral over the aortic valve in the apical 5-chamber view or the apical long axis view [ml] between the conditions at rest and during exercise, measured by speckle tracking strain analysis according to the guidelines of the European Association of Cardiology.
Measured: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
Heart rate
Differences in heart rate [bpm] and HRV between the conditions at rest and during exercise, continuously measured throughout the intervention by electrocardiogram connected to an Alice pdx.
Measured: It will be assessed at baseline and continuously measured during each condition (1 hour resting period and during the 10 minutes cycling).
Blood pressure
Differences in blood pressure between the conditions at rest and during exercise, measured by a digital sphygmomanometer four times at rest and four times during low load cycling [mmHg] and continuously measured by a PPG-based Wrist-monitor (biobeat).
Measured: It will be measured at baseline once and during each condition six times: Four times during the resting period (every 15 min) and two times during low load cycling.
Borg Rating of Perceived Exertion Scale (CR10)
Differences in Borg Rating of Perceived Exertion Scale (CR10) between the conditions at rest and during exercise. Measured through showing a paper with the 10 categories and the participant points to the according category which describes the current breathing difficulty.
Measured: Measured at baseline and in each condition twice: Once at the end of the resting condition and again at the end of the cycling exercise.
Oxygen saturation
Differences in oxygen saturation [%] between the conditions at rest and during exercise, continuously measured throughout the intervention by an oximeter connected to an Alice pdx.
Measured: It will be assessed at baseline and continuously measured during each condition (1 hour resting period and during the 10 minutes cycling).
Lung tissue oxygenation
Differences in lung tissue oxygenation between the conditions at rest and during exercise, assessed using near infrared spectroscopy (NIRS) continuously measured throughout the intervention according to our SOP.
Measured: It will be assessed at baseline and continuously measured during each condition (1 hour resting period and during the 10 minutes cycling).
Brain oxygenation
Differences in brain oxygenation between the conditions at rest and during exercise, assessed using near infrared spectroscopy (NIRS) continuously measured throughout the intervention according to our SOP.
Measured: It will be assessed at baseline and continuously measured during the 1 hour resting period during each condition, and during the 10 minutes cycling.
Respiratory effort
Differences in respiratory effort abdominal and chest using zRIP belts between the conditions at rest and during exercise connected to an Alice pdx.
Measured: It will be assessed at baseline and continuously measured during each condition (1 hour resting period and during the 10 minutes cycling).
Multiomics profiles
Differences in multiomics profiles between the conditions at rest, assessed using mass spectrometry analysis of blood serum collected from venous blood from the V. antecubita, will be evaluated to determine the effects of acute hypoxia and group-specific responses.
Measured: A blood sample will be collected during each condition after 1 hour of rest.
Arterial blood gas analysis
Differences in arterial blood gas analysis (ABGA) between the conditions at rest, collected through puncture of the A. radialis by a trained physician.
Measured: A blood sample will be collected during each condition after 1 hour of rest.
Right ventricular size
Differences in right ventricular size between the conditions at rest and during exercise, measured according to the guidelines of the European Association of cardiology.
Measured: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
End-diastolic diameter
Differences in end-diastolic diameter between the conditions at rest and during exercise, measured according to the guidelines of the European Association of cardiology.
Measured: It will be assessed once at baseline and once during each condition after the resting period.
Fractional area change
Differences in fractional area change between the conditions at rest and during exercise, measured according to the guidelines of the European Association of cardiology.
Measured: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
Maximal tricuspid regurgitation velocity
Differences in maximal tricuspid regurgitation velocity between the conditions at rest and during exercise, measured according to the guidelines of the European Association of cardiology.
Measured: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
Pulmonary acceleration time
Differences in pulmonary acceleration time between the conditions at rest and during exercise, measured according to the guidelines of the European Association of cardiology.
Measured: It will be assessed once at baseline and once during each condition after the resting period.
Diastolic dysfunction grade
Differences in diastolic dysfunction grade between the conditions at rest and during exercise, measured according to the guidelines of the European Association of cardiology.
Measured: It will be assessed once at baseline and once during each condition after the resting period.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Feb 2026
- Study start26 May 2026
- Primary completionJan 2030 (estimated)
- Study completionJan 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hypoxia, AltitudeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Single-center, double-blind, randomized controlled, cross-over study.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 18 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Mona Lichtblau
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Mona Lichtblau, University of Zurich
- Investigators
- Mona Lichtblau, Principal investigator, University of Zurich
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07431580
- Sponsor's protocol ID
- RIVER-Asthma
- Acronym
- RIVER-Asthma
- Status last verified
- May 2026
- First submitted
- 9 Feb 2026
- Last updated
- 29 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: Anonymized individual participant data (IPD) are planned to be shared via an appropriate data repository, such as Zenodo. Corresponding standard operating procedures (SOPs) for our department are currently under development.
Study at a glance
From the registry record, last updated by the sponsor on 29 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Acute Hypoxia on RIght VEntRicular Function. A Single-Center, Double-Blind, Randomized Controlled Cross-Over Trial.
- ClinicalTrials.gov ID
- NCT07431580
- Acronym / sponsor ID
- RIVER-Asthma / RIVER-Asthma
- Keywords
- right ventricular free wall strain, RVFWS, right ventricular function, tissue oxygenation, breathing difficulty, blood gas, heart rate
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 18 participants (estimated)
- Lead sponsor
- Mona LichtblauUniversity, hospital or other
- Study start
- 26 May 2026 (actual)
- Primary completion
- Jan 2030 (estimated)
- Study completion
- Jan 2030 (estimated)
- First posted
- 24 Feb 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
More and more people are engaging in sports in the mountains, including individuals with heart or lung diseases. At the same time, such diseases are becoming more common in Switzerland. At high altitude, less oxygen is available, which places stress on the body-particularly on the heart, which has to pump blood through the lungs. How the heart, especially the right ventricle, in people with asthma responds to this stress is still not well understood.
Therefore, this study investigates how the heart responds to simulated altitudes of 2,500 m and 4,000 m, both at rest and during light physical activity in patients with asthma. The primary objective is to assess how right ventricular function changes under conditions of reduced oxygen availability.
In addition, vital signs, changes in blood gases, oxygen levels in blood and tissue and shortness of breath are assessed. The "altitude" is simulated using a special gas mixture that participants inhale. Participants undergo three altitude conditions (490, 2,500, and 4,000 m above sea level). The order of the altitude conditions is assigned at random.
The aim is to better understand how the right ventricle and other parameters respond to low-oxygen conditions and how affected patients can be better supported in the future.
Detailed description
Outdoor activities in the mountains are becoming increasingly popular. At higher altitudes, the air contains less oxygen, which puts extra strain on the body-especially on the heart. The right side of the heart plays a key role in pumping blood through the lungs and may need to work harder when oxygen levels are low. While the heart's response to long-term altitude exposure is relatively well known, much less is understood about how the heart reacts to short-term (acute) exposure to low oxygen, particularly during light physical activity and in individuals with asthma.
This study aims to better understand how the right ventricle responds to short-term simulated altitude exposure. Participants with asthma will be exposed to different oxygen levels that correspond to altitudes of 490 m (near sea level), 2,500 m, and 4,000 m, both at rest and during light cycling exercise.
The main focus of the study is to measure changes in right ventricular function, assessed using a non-invasive heart ultrasound technique called speckle-tracking echocardiography. In addition, heart rate, blood pressure, oxygen saturation, and symptoms such as shortness of breath and leg fatigue will be recorded.
The study is conducted at a single center and uses a randomized, double-blind, cross-over design, meaning that each participant undergoes all altitude conditions in a random order, and neither the participants nor the investigators know which altitude is being simulated at a given time.
Participants Only adults aged 18-80 years with diagnosed asthma bronchiale will be included. Participants must live below 800 m above sea level and must not have been exposed to higher altitudes for more than 24 hours in the three weeks before participation. Individuals with significant other medical conditions, pregnancy, need for long-term oxygen therapy, or inability to follow the study procedures will be excluded.
Study procedures
Each study visit includes:
- 1 hour resting period
- Measurement of vital signs (heart rate, blood pressure, oxygen saturation)
- Heart ultrasound at rest
- A 10-minute low-intensity cycling exercise
- Repeated heart ultrasound during and symptom assessment after exercise
- Low-oxygen conditions are created using a special gas mixture that participants breathe through a mask. Each condition is separated by at least 2 hours wash-out period to ensure recovery.
Study size and duration Based on statistical calculations, 18 participants will be recruited to allow balanced allocation across all study conditions and to account for potential dropouts. Participation may take place over two to three days, depending on the preferred schedule of the participant. The days can be spread or be spread over several weeks, depending on individual availability.
Aim of the study The goal of this study is to improve understanding of how the right side of the heart responds to short-term low-oxygen exposure at rest and during light exercise. This knowledge will help interpret future findings in patients with heart or lung disease and may contribute to safer recommendations for physical activity at altitude.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 6
- Model description
- Single-center, double-blind, randomized controlled, cross-over study.
| Arm | Type | Receives |
|---|---|---|
| Arm ABC (normobaric normoxia - normobaric hypoxia 2500m - normobaric hypoxia 4000m) | Other | Other: Normobaric HypoxiaThe participant receives first normobaric normoxia (A), then normobaric hypoxia equal to 2500 m.a.s.l. (B) then normobaric hypoxia representing 4000 m.a.s.l. (C). Condition A represents the control. |
| Arm ACB (normobaric normoxia - normobaric hypoxia 4000m - normobaric hypoxia 2500m) | Other | Other: Normobaric HypoxiaThe participant receives first normobaric normoxia (A), then normobaric hypoxia representing 4000 m.a.s.l. (C), then normobaric hypoxia equal to 2500 m.a.s.l. (B). Condition A represents the control. |
| Arm BAC (normobaric hypoxia 2500m - normobaric normoxia - normobaric hypoxia 4000m) | Other | Other: Normobaric HypoxiaThe participant receives first normobaric hypoxia equal to 2500 m.a.s.l. (B), then normobaric normoxia (A), then normobaric hypoxia representing 4000 m.a.s.l. (C). Condition A represents the control. |
| Arm BCA (normobaric hypoxia 2500m - normobaric hypoxia 4000m - normobaric normoxia) | Other | Other: Normobaric HypoxiaThe participant receives first normobaric hypoxia equal to 2500 m.a.s.l. (B), then normobaric hypoxia representing 4000 m.a.s.l. (C), then normobaric normoxia (A). Condition A represents the control. |
| Arm CAB (normobaric hypoxia 4000m - normobaric normoxia - normobaric hypoxia 2500m) | Other | Other: Normobaric HypoxiaThe participant receives first normobaric hypoxia representing 4000 m.a.s.l. (C), then normobaric normoxia (A), then normobaric hypoxia equal to 2500 m.a.s.l. (B). Condition A represents the control. |
| Arm CBA (normobaric hypoxia 4000m - normobaric hypoxia 2500m - normobaric normoxia) | Other | Other: Normobaric HypoxiaThe participant receives first normobaric hypoxia representing 4000 m.a.s.l. (C), then normobaric hypoxia equal to 2500 m.a.s.l. (B), then normobaric normoxia (A). Condition A represents the control. |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Signed informed consent
- Diagnosed and well controlled asthma bronchiale
- 18-80 years (age group young: 18-39.99 years / age group older: 40-80 years)
- All sex and genders
- Living <800m and without altitude exposure > 2500 m and > 24h within the last three weeks
Key exclusion criteria (8 listed)
- <18, >80 years old
- Any other diagnosed cardiopulmonary condition including past HAPE
- Other clinically significant severe concomitant disease states (e.g. renal, hepatic dysfunction, etc.)
- Inability to follow the procedures of the study due to language problems, psychological neurological disorders or orthopaedic disorders
- Participants permanently living >800m and altitude exposure > 2500 m and >24h within the last three weeks
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Normobaric HypoxiaAlso: rest, low intensity cycling, normobaric normoxiaNormobaric hypoxia according to 408m (control/normobaric normoxia), 2500 m and 4000 m above sea-level at rest for 1 hour and at low intensity cycling for 10 minutes (5 min 30 W, 5 min 60 W). | Other | Arm ABC (normobaric normoxia - normobaric hypoxia 2500m - normobaric hypoxia 4000m), Arm ACB (normobaric normoxia - normobaric hypoxia 4000m - normobaric hypoxia 2500m), Arm BAC (normobaric hypoxia 2500m - normobaric normoxia - normobaric hypoxia 4000m), Arm BCA (normobaric hypoxia 2500m - normobaric hypoxia 4000m - normobaric normoxia), Arm CAB (normobaric hypoxia 4000m - normobaric normoxia - normobaric hypoxia 2500m), Arm CBA (normobaric hypoxia 4000m - normobaric hypoxia 2500m - normobaric normoxia) |
Primary outcome
Right ventricular free wall strain
Time frame: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
The primary endpoint is defined as the right ventricular free wall strain (RVFWS) from condition normobaric normoxia to condition 4000m for group 1 and from normobaric normoxia to condition 2500m for group 2 at rest. RVFWS will be measured by speckle tracking strain analysis according to the guidelines of the European Association of Cardiology. Speckle tracking echocardiography allows to assess the right ventricular volume and true global RV function without relying on geometric assumption and is a valuable clinical bedside tool for assessing myocardial strain. Tomtec software (Philipps) will be used.
19 secondary outcomes
Tricuspid annular plane systolic excursion (TAPSE)
Time frame: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
Right ventricular-arterial coupling
Time frame: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
RV/PA
Time frame: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
Stroke volume
Time frame: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
Heart rate
Time frame: It will be assessed at baseline and continuously measured during each condition (1 hour resting period and during the 10 minutes cycling).
Blood pressure
Time frame: It will be measured at baseline once and during each condition six times: Four times during the resting period (every 15 min) and two times during low load cycling.
Borg Rating of Perceived Exertion Scale (CR10)
Time frame: Measured at baseline and in each condition twice: Once at the end of the resting condition and again at the end of the cycling exercise.
Oxygen saturation
Time frame: It will be assessed at baseline and continuously measured during each condition (1 hour resting period and during the 10 minutes cycling).
Lung tissue oxygenation
Time frame: It will be assessed at baseline and continuously measured during each condition (1 hour resting period and during the 10 minutes cycling).
Brain oxygenation
Time frame: It will be assessed at baseline and continuously measured during the 1 hour resting period during each condition, and during the 10 minutes cycling.
Respiratory effort
Time frame: It will be assessed at baseline and continuously measured during each condition (1 hour resting period and during the 10 minutes cycling).
Multiomics profiles
Time frame: A blood sample will be collected during each condition after 1 hour of rest.
Arterial blood gas analysis
Time frame: A blood sample will be collected during each condition after 1 hour of rest.
Right ventricular size
Time frame: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
End-diastolic diameter
Time frame: It will be assessed once at baseline and once during each condition after the resting period.
Fractional area change
Time frame: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
Maximal tricuspid regurgitation velocity
Time frame: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.
Pulmonary acceleration time
Time frame: It will be assessed once at baseline and once during each condition after the resting period.
Diastolic dysfunction grade
Time frame: It will be assessed once at baseline and once during each condition after the resting period.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 May 2026.
- Individual participant dataSharing planned: Undecided. Anonymized individual participant data (IPD) are planned to be shared via an appropriate data repository, such as Zenodo. Corresponding standard operating procedures (SOPs) for our department are currently under development.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Mona Lichtblau principal investigator
University of Zurich
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Normobaric Hypoxia in people with Hypoxia, Altitude and Hypoxia, run by Mona Lichtblau at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 29 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Mona Lichtblau, PD Dr. med. (+41 442552220, mona.lichtblau@usz.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Right ventricular free wall strain (time frame: It will be assessed once at baseline in rest and during each condition three times: Once after 1 hour in the specific condition at rest, then during the 5 min of 30 Watt cycling and during the 5 min of 60 Watt cycling.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 May 2026.