"Hypoxic vs. Aerobic Training in Chronic Kidney Disease

NCT ID: NCT07180875

Last Updated: 2025-12-24

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 60 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-12-09
• Study Completion Date: 2026-02-01

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

Conditions

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

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

Hypoventilation Training group

• 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

Group Type: EXPERIMENTAL

hypoventilation group

Intervention Type: BEHAVIORAL

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

Breathing Restriction Mask Training

• 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.

Group Type: EXPERIMENTAL

hypoventilation group

Intervention Type: BEHAVIORAL

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

Control Group (Conventional Aerobic Training)

• 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

Group Type: ACTIVE_COMPARATOR

hypoventilation group

Intervention Type: BEHAVIORAL

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

Interventions

hypoventilation 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

Intervention Type: BEHAVIORAL

Other Intervention Names

Breathing Restriction Mask Training

Eligibility Criteria

Inclusion Criteria

• Medically stable and cleared for exercise

Exclusion Criteria

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

cardiovascular disese unstable

• Minimum Eligible Age: 40 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Pharos University in Alexandria

OTHER

Sponsor Role: lead

Responsible Party

Ola Mohamed Elsayed Elgohary

ola mohamed elgohary

Responsibility Role: PRINCIPAL_INVESTIGATOR

Other Identifiers

OlaElgohary-IHT-CKD-01

Identifier Type: -

Identifier Source: org_study_id