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NCT Number: NCT07797088

Assessment of Six-minute Walking Distance Between Sea Level LA vs. High Altitude HA After Re-ascent in Healthy Individuals

To study the effect of a re-ascent after a one-week stay at sea level (after prior descent from 2850m) to high altitude (Quito Ecuador: 2850m) on six-minute walking distance and other scores in healthy individuals, who live permanently >2600m.

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Key information

Conditions

High Altitude Altitude Sickness Healthy Healthy Adult High Altitude Effects Hypoxia Pathological Conditions, Signs and Symptoms Respiration Disorders Respiratory Tract Diseases Signs and Symptoms Signs and Symptoms, Respiratory Six-minute Walk Test

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University Hospital of Zurich

Zurich, Switzerland

About this study

The aim of this research is to investigate the six-minute walking distance and other scores before and after re-ascent (sea level for 7 days vs. re-ascent to 2850m) in healthy individuals, who permanently live at high altitude over 2600m.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults aged 18-80 years and of all genders
  • Permanent residence > 2600 m
  • healthy: no self-perceived cardiopulmonary disease limiting daily activities
  • written informed consent to participate in the study.

Exclusion criteria

  • Age <18 years or >80 years
  • Participants who cannot follow the study investigations
  • Participants permanently living < 2600m
  • Participants who traveled and stayed overnight at altitudes <2000 m in the past 4 weeks.
  • any self-perceived cardiopulmonary disease limiting daily activities

Treatment and study plan

Re-Ascent sea level to 2850m

Behavioral

After 7 days at sea level return/re-ascent to their usual living altitude at 2850m

Primary outcomes

  1. Six-minute walking distance after re-ascent to 2850m

    Time frame: From Day 5-7 at sea level to the day after re-ascent

    Difference/change in six-minute walking distance 6MWD between sea level (after one-week stay) and day after re-ascent at 2850m in healthy individuals

Secondary outcomes

  1. SpO2 at rest and end-exercise after re-ascent to 2850m

    Time frame: From Day 5-7 at sea level to the day after re-ascent

    Difference/change in SpO2 (peripheral oxygen saturation) at rest and end-exercise between sea level (after one-week stay) and Day after re-ascent to 2850m in healthy individuals

  2. Heart rate at rest and end-exercise after re-ascent to 2850m

    Time frame: From Day 5-7 at sea level to the day after re-ascent

    Difference/change in heart rate at rest and end-exercise between sea level (after one-week stay) and Day after re-ascent to 2850m in healthy individuals

  3. Blood pressure at rest and end-exercise after re-ascent to 2850m

    Time frame: From Day 5-7 at sea level to the day after re-ascent

    Difference/change in blood pressure at rest and end-exercise between sea level (after one-week stay) and Day after re-ascent to 2850m in healthy individuals

  4. Dyspnea and leg discomfort sensation after re-ascent to 2850m

    Time frame: From Day 5-7 at sea level to the day after re-ascent

    Difference/change in dyspnea and leg discomfort sensation (assessed with BORG-CR10-Scale, Category Rating 0-10 with 10 being the most dyspnea/leg discomfort) at rest and end-exercise between sea level (after one-week stay) and day after re-ascent to 2850m in healthy individuals

  5. NYHA functional class after re-ascent to 2850m

    Time frame: From Day 5-7 at sea level to the day after re-ascent

    Difference/change in NYHA functional class (New York Heart Association Class I-IV, IV being the worst) at rest and end-exercise between sea level (after one-week stay) and day after re-ascent to 2850m in healthy individuals

  6. Quality of life after re-ascent to 2850m

    Time frame: From Day 5-7 at sea level to the day after re-ascent

    Difference/change in quality of life score (EmPHasis-10: Score with 10 questions and 0-50 points, higher scores indicating poorer quality of life) between sea level (after one-week stay) and day after re-ascent to 2850m in healthy individuals

  7. General well-being after re-ascent to 2850m

    Time frame: From Day 5-7 at sea level to the day after re-ascent

    Difference/change in general well-being (Visual Analog Scale 10cm: the higher, the worse) between sea level (after one-week stay) and day after re-ascent to 2850m in healthy individuals

  8. Six-minute walking test pre-descent to after re-ascent

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in six-minute walking distance (6MWD) at 2850m with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in healthy individuals

  9. SpO2 at rest and end-exercise pre-descent to after re-ascent

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in SpO2 (peripheral oxygen saturation) at rest and end-exercise with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in healthy individuals

  10. Heart rate at rest and end-exercise pre-descent to after re-ascent

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in heart rate at rest and end-exercise with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in healthy individuals

  11. Blood pressure at rest and end-exercise pre-descent to after re-ascent

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in blood pressure at rest and end-exercise with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in healthy individuals

  12. Dyspnea and leg discomfort pre-descent to after re-ascent

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in dyspnea and leg discomfort (assessed with BORG-CR10-Scale, Category Rating 0-10 with 10 being the most dyspnea/leg discomfort) at rest and end-exercise with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in healthy individuals

  13. NYHA functional class pre-descent to after re-ascent

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in NYHA functional class (New York Heart Association Class I-IV, IV being the worst) at 2850m with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in healthy individuals

  14. Quality of life pre-descent to after re-ascent

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in quality of life (EmPHasis-10: Score with 10 questions and 0-50 points, higher scores indicating poorer quality of life) with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in healthy individuals

  15. General well-being pre-descent to after re-ascent

    Time frame: Baseline at 2850m followed by a one-week stay at sea level to the day after re-ascent back to 2850m (time frame approximately 11 days)

    Difference/change in general well-being (Visual Analog Scale 10cm: the higher, the worse) with a one-week stay at sea level in between (day pre-descent vs. day after re-ascent) in healthy individuals

Study contacts

Contact information is provided by the study sponsor or research team.

Michael Furian, Prof. Dr. sc. ETH

CONTACT

+41442552220

Silvia Ulrich, Prof. Dr. med.

CONTACT

[email protected]

+41442552220

Sponsors and collaborators

Lead sponsor

Silvia Ulrich Somaini

Other

Registry information

Official study title

Effect of a One-week Descent From 2850m to Sea Level and Re-ascent in Patients With Pulmonary Arterial Hypertension and Healthy Controls Permanently Living > 2600m on Pulmonary Hemodynamics, Exercise Capacity, Blood Oxygenation, Sleep Disordered Breathing and Further Outcomes

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Sep 1, 2026
Registry last updated
Sep 1, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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