Chronic Kidney Disease (CKD), Stages 3-4 Exercise Tolerance / Functional Capacity Vascular Health / Arterial Stiffness Fatigue in CKDIHT-CKDNCT07180875
"Hypoxic vs. Aerobic Training in Chronic Kidney Disease
A study testing hypoventilation group in people with Chronic Kidney Disease (CKD), Stages 3-4 Exercise Tolerance / Functional Capacity Vascular Health / Arterial Stiffness Fatigue in CKD, run by Pharos University in Alexandria.
Trial summary
Chronic kidney disease (CKD) leads to poor exercise tolerance, vascular dysfunction, and reduced quality of life. This randomized controlled trial will compare intermittent hypoxic training (IHT) with traditional aerobic training in patients with CKD stages 3-4. Read more about this study
- Who is it for?
- Ages 40 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Chronic Kidney Disease (CKD), Stages 3-4 Exercise Tolerance / Functional Capacity Vascular Health / Arterial Stiffness Fatigue in CKD
- What is being tested?
- hypoventilation group
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- No sites listed yet
- Study dates
- 9 Dec 2025to 1 Feb 2026
- Phase
- Interventional
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 40 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
None listed.
Who cannot join
- Uncontrolled hypertension
- Severe cardiac arrhythmias
- Recent hospitalization (<3 months)
- cardiovascular disese unstable
About this study
Official title: Simulated Hypoxia Training to Enhance Exercise Tolerance in Stage 3 Chronic Kidney Disease: A Randomized Controlled Trial
Chronic kidney disease (CKD) leads to poor exercise tolerance, vascular dysfunction, and reduced quality of life. This randomized controlled trial will compare intermittent hypoxic training (IHT) with traditional aerobic training in patients with CKD stages 3-4.
A total of 60 participants aged 40-65 years will be recruited and randomized into three groups. Interventions will last 12 weeks, with three 30-minute supervised sessions per week. Outcome measures include exercise tolerance (6-Minute Walk Test), cardiovascular parameters (blood pressure, heart rate recovery), kidney function (serum creatinine, eGFR), fatigue (Fatigue Severity Scale), and quality of life (KDQOL-36)
Read the detailed description
Chronic kidney disease (CKD) stage 3 is characterized by reduced exercise capacity, muscle weakness, and increased cardiovascular risk, which negatively impact quality of life. Exercise interventions have shown benefits in improving functional outcomes, but traditional aerobic training may be limited due to comorbidities and reduced physiological reserve. Intermittent hypoxic training (IHT) improves oxygen utilization, cardiovascular adaptation, and mitochondrial function. Specialized hypoxicator devices are costly and not widely available, so practical alternatives such as hypoventilation training and breathing restriction masks may provide comparable benefits.
Study Objective:
To evaluate the effects of hypoventilation training and breathing restriction mask training on exercise tolerance, cardiovascular function, kidney function, fatigue, and quality of life in CKD stage 3 patients.
Study Design:
Randomized controlled trial including 60 patients with CKD stage 3, aged 40-65 years, recruited from outpatient clinics at Aboker Hospital and Pharos University. Participants will be screened for eligibility through medical history, vital signs, and laboratory tests (serum creatinine, eGFR, hemoglobin, electrolytes).
Interventions:
Group A - Hypoventilation Training:
Moderate-intensity aerobic exercise on a cycle ergometer (40-60% HR reserve)
Intermittent breath-holding: 5-10 seconds every 1-2 minutes
Continuous monitoring of SpO₂, heart rate, and blood pressure
Group B - Breathing Restriction Mask Training:
Same aerobic protocol as Group A
Participants wear an adjustable resistance mask to simulate hypoxia
Mask set to induce mild hypoxemia (SpO₂ ≥85%)
Continuous monitoring of SpO₂, heart rate, and blood pressure
Group C - Control Group:
Same aerobic exercise protocol under normal breathing conditions
Moderate intensity (40-60% HR reserve)
Periodic monitoring of vital signs for safety
Intervention Duration:
12 weeks, 3 supervised sessions per week, 30 minutes per session
Outcome Measures:
Primary Outcome:
Exercise tolerance assessed via 6-Minute Walk Test (6MWT) at baseline and post-intervention
Secondary Outcomes:
Fatigue: Fatigue Severity Scale (FSS), self-reported, 9 items, 7-point Likert scale
Quality of Life: KDQOL-36, disease-specific questionnaire covering physical/mental health, symptoms, effects, and burden of CKD
Cardiovascular Assessment: Blood pressure (SBP, DBP) and Heart Rate Recovery (HRR = HR_peak - HR_1min)
Kidney Function: Serum creatinine and eGFR (CKD-EPI/MDRD
- Being tested
- hypoventilation group
- Medical subject headings
- Renal Insufficiency, Chronic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
hypoventilation groupBehavioural
Also called Breathing Restriction Mask Training
Traditional Aerobic Training Participants will perform supervised aerobic exercise (e.g., cycling or treadmill walking) under controlled intermittent hypoxic conditions.
Hypoxia protocol: alternating cycles of low-oxygen exposure (FiO₂ 12-16%) for 3-5 minutes followed by normoxic recovery for 2-3 minutes, repeated 6-8 times per session.
Frequency: 3 sessions per week for 12 weeks.
Exercise intensity: Moderate (50-70% of heart rate reserve), adjusted individually based on baseline exercise testing
| Study group | Role | What they receive |
|---|---|---|
| Hypoventilation Training group | Experimental | * Mode: Stationary cycling (ergometer).
* Intensity: Moderate (40-60% VO₂max or Borg RPE 11-13).
* Duration: 30 minutes per session.
* Frequency: 3 sessions per week, for 12 weeks.
* Technique:
* Patients instructed to hold their breath (hypoventilation) for 5-10 seconds every 2-3 minutes during cycling.
* Breathing then resumes normally until recovery.
* Cycle repeated throughout the session Receives: Behavioral: hypoventilation group |
| Breathing Restriction Mask Training | Experimental | * Mode: Stationary cycling (ergometer).
* Intensity: Moderate (same as Group A: 40-60% VO₂max).
* Duration: 30 minutes per session.
* Frequency: 3 sessions per week, for 12 weeks.
* Equipment: Commercially available breathing restriction mask (e.g., altitude simulation mask).
* Technique:
* Mask settings adjusted to provide increasing resistance over time, simulating hypoxic breathing (FiO₂ ~14-16%).
* Patients cycle continuously with mask worn throughout the session.
* Monitoring:
* SpO₂, HR, BP monitored continuously.
* Mask removed immediately if SpO₂ < 88% or severe dyspnea occurs. Receives: Behavioral: hypoventilation group |
| Control Group (Conventional Aerobic Training) | Active comparator | * Mode: Stationary cycling (ergometer).
* Intensity: Moderate (40-60% VO₂max or Borg RPE 11-13).
* Duration: 30 minutes per session.
* Frequency: 3 sessions per week, for 12 weeks.
* Technique:
* Continuous cycling at steady pace.
* No hypoventilation or mask used.
* Monitoring:
o HR, BP, and SpO₂ checked pre- and post-session.
* Progression:
* Workload (watts) increased every 2-3 weeks to maintain moderate intensity Receives: Behavioral: hypoventilation group |
What is being measured
The primary outcome is the main question the study is designed to answer.
Six-Minute Walk Test (6MWT) distance
Straightforward standardized 6-minute corridor walk performed according to ATS guidelines. Participants walk back and forth along a marked 30-meter course for 6 minutes; standardized instructions and encouragement are given. Total distance walked (meters) recorded. Assessors are blinded to group allocation.
Measured: 12 weeks
Secondary outcomes (2)
Fatigue Severity Scale (FSS)
A validated 9-item self-report questionnaire assessing the impact and severity of fatigue on daily functioning. Each item is rated on a 7-point Likert scale; higher scores indicate greater fatigue.
Measured: 12 wwks
Kidney Disease Quality of Life Questionnaire (KDQOL-36)
A disease-specific quality of life tool combining general health status (SF-12) and kidney disease-targeted domains (symptoms/problems, effects, and burden of kidney disease). Scores are standardized (0-100), with higher scores indicating better quality of life
Measured: 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Sep 2025
- Study start9 Dec 2025 (estimated)
- Primary completion15 Jan 2026 (estimated)
- Study completion1 Feb 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Chronic Kidney Disease (CKD), Stages 3-4 Exercise Tolerance / Functional Capacity Vascular Health / Arterial Stiffness Fatigue in CKDStudies 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Pharos University in Alexandria
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ola Mohamed Elsayed Elgohary, Pharos University in Alexandria
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07180875
- Sponsor's protocol ID
- OlaElgohary-IHT-CKD-01
- Acronym
- IHT-CKD
- Status last verified
- Sep 2025
- First submitted
- 12 Sep 2025
- Last updated
- 24 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: This study will compare the effects of intermittent hypoxic training (IHT) versus traditional aerobic training (TAT) on exercise tolerance and vascular health in patients with chronic kidney disease (CKD) stages 2-4. Participants will be randomized into two intervention groups and undergo supervised exercise sessions over a 12-week period. Primary outcomes include peak oxygen uptake (V̇O₂peak) and endothelial function (flow-mediated dilation), while secondary outcomes include arterial stiffness, 6-minute walk distance, and quality of life measures. Safety and adherence will be closely monitored throughout the study. Data will be analyzed to determine the comparative efficacy of IHT and TAT in improving functional and vascular health in this population