Chronic Kidney Disease (CKD), Stages 3-4 Exercise Tolerance / Functional Capacity Vascular Health / Arterial Stiffness Fatigue in CKD
Conditions
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
Interventions
BEHAVIORALhypoventilation group
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
Sponsors
Pharos University in Alexandria
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Masking description
Masking Description: Outcome assessors and data analysts will be blinded to group allocation; participants and trainers cannot be blinded due to the nature of the intervention
Eligibility
Sex/Gender
ALL
Age
40 Years to 65 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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
| Measure | Time frame | Description |
|---|---|---|
| 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 |
Outcome results
None listed