"Hypoxic vs. Aerobic Training in Chronic Kidney Disease

Not Applicable

Not yet recruiting

• Conditions: Chronic Kidney Disease (CKD), Stages 3-4 Exercise Tolerance / Functional Capacity Vascular Health / Arterial Stiffness Fatigue in CKD

• Registration Number: NCT07180875
• Lead Sponsor: Pharos University in Alexandria

Brief 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.

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)

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

Study Timeline

• Status Verified: 2025-09
• Study First Submitted: 2025-09-12
• Study First Submitted QC: 2025-09-12
• Study First Posted: 2025-09-18
• Last Update Submitted: 2025-09-19
• Last Update Posted: 2025-09-24
• Study Start: 2025-10-01
• Primary Completion: 2026-01-15
• Study Completion: 2026-02-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 60

Inclusion Criteria

Adults (40-65 years) diagnosed with CKD stages 3a,b

• Medically stable and cleared for exercise

Exclusion Criteria

• Uncontrolled hypertension
• Severe cardiac arrhythmias
• Recent hospitalization (<3 months)

cardiovascular disese unstable

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Six-Minute Walk Test (6MWT) distance	12 weeks	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.

Secondary Outcome Measures

Name	Time	Method
Fatigue Severity Scale (FSS)	12 wwks	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.
Kidney Disease Quality of Life Questionnaire (KDQOL-36)	12 weeks	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