Investigating the Combined Effects of Intermittent Hypoxia and Exercise on Cognitive and Cerebral Function in Middle-Aged Adults

Official title

Towards a Better Understanding of the Combination of Intermittent Hypoxia and Physical Exercise: Comparison of Effects on Cognitive and Cerebral Capacities in Middle-Aged Adults

Overview

This study investigates whether intermittent hypoxia (IH) and physical activity (PA), either alone or in combination (simultaneously or sequentially), can improve cognitive function and brain health in middle-aged adults (50-65 years old). The hypothesis is that (1) each intervention alone (IHT or PA) provides cognitive benefits and (2) combining IHT with PA may yield additive or synergistic effects, particularly when administered simultaneously rather than sequentially. By comparing these distinct interventions, the study aims to determine which approach best preserves or enhances cognitive performance in middle-aged adults. Findings from this research may inform non-pharmacological strategies to promote healthy aging and reduce the risk of age-related cognitive decline.

Detailed description

Rapid demographic aging worldwide is driving a surge in age-related conditions, including neurodegenerative diseases and cognitive disorders. Projections estimate that the number of people living with dementia could reach 78 million by 2030 and 139 million by 2050, underscoring the urgent need for effective, non-pharmacological strategies to preserve brain health. Intermittent hypoxia (IH) and physical activity (PA) are two promising interventions that may help prevent or mitigate cognitive decline. IH-an approach involving repeated cycles of reduced oxygen (11-16% FiO₂) followed by normoxic recovery-has shown benefits across diverse health domains (cardiovascular, metabolic, respiratory, and neurological), potentially through mechanisms such as the activation of Hypoxia-Inducible Factor (HIF), enhanced vascular endothelial growth factor (VEGF) production, and anti-apoptotic pathways. PA is widely recognized for its positive impact on overall health, including cognitive function and neuroplasticity.

The primary objective of this study is to evaluate the effects of IH and PA-administered individually, sequentially, or simultaneously-on cognitive performance and brain health in adults aged 50 to 65. The study will determine whether combining these interventions produces additive or synergistic benefits beyond those observed with each intervention alone. A total of approximately 176 participants will be enrolled and randomly assigned to one of five groups: (1) PA only, (2) IH only, (3) PA + IH sequentially, (4) PA + IH simultaneously, or (5) a control group receiving "placebo" hypoxia. Each participant will complete 18 sessions over a 6-week period (3 sessions per week), with sessions conducted in a hypoxic chamber at CIC 1402 and at the exercise testing facility of the University of Poitiers.

Outcome measures include comprehensive cognitive testing (global cognition, reaction time, executive function, and divided attention), assessments of autonomy (e.g., activities of daily living), and physiological parameters (e.g., SpO₂, cerebral oxygenation, heart rate, and blood pressure). Biomarker analysis will include brain-derived neurotrophic factor (BDNF), VEGF, irisin, and markers of HIF activation to elucidate the mechanisms underlying any observed improvements. Vascular function will be assessed using Doppler ultrasound and near-infrared spectroscopy (NIRS), and daily activity levels will be monitored with accelerometers.

Inclusion criteria require participants to be 50-65 years old, with a Montreal Cognitive Assessment (MoCA) score ≥24, no participation in other exercise interventions in the past 6 months, and no altitude exposure above 1,500 m in the preceding 3 months. Additional eligibility requirements include the absence of chronic kidney, cardiovascular, metabolic, neurological, or orthopedic disease, as well as no significant respiratory history. Exclusion criteria include active smoking, major cardiovascular complications within the last 3 months, severe hypertension, chronic respiratory insufficiency, diabetes, or any other condition that could compromise safety or study compliance. A qualified medical doctor will confirm eligibility during the inclusion process.

By evaluating different delivery methods of IH and PA, this research aims to identify the most effective, non-pharmacological approach to preserving-or potentially enhancing-cognitive function in middle-aged adults. Findings may contribute to targeted preventive strategies and novel therapeutic interventions, addressing the growing public health burden of age-related cognitive decline.

Interventions

• Other Hypoxia, intermittent
  Moderate-Intensity Aerobic Exercise (\~60-70% of maximum heart rate) and Intermittent Hypoxia (maintained between 80-90% during hypoxic phases)
• Other physical exercise
  Moderate-Intensity Aerobic Exercise (\~60-70% of maximum heart rate)
• Other Sham (No Treatment) hypoxia
  Exposure to normoxic air (FiO₂ \~20.9%) instead of actual hypoxia.

Primary outcome measures

• Cognitive Function: Montreal Cognitive Assessment (MoCA) [Time frame: Baseline (Week 0),Week 1 (after 3 sessions), Week 6 (post-intervention, after session 18)]
• Cerebral Oxygenation - Tissue Saturation Index (TSI) [Time frame: Baseline (Week 0), Week 1 (after 3 sessions), Week 6 (post-intervention, after session 18)]
• Biomarker Analysis- Brain-Derived Neurotrophic Factor (BDNF) Levels [Time frame: Baseline (Week 0), Week 1 (after 3 sessions), Week 6 (post-intervention, after session 18)]
• Cerebral blood flow [Time frame: Baseline (Week 0), Week 1 (after 3 sessions), Week 6 (post-intervention, after session 18)]
• Cognitive Function: Stroop Test [Time frame: Baseline (Week 0), Week 1 (after 3 sessions), Week 6 (post-intervention, after session 18)]
• Cognitive Function: N-Back [Time frame: Baseline (Week 0),Week 1 (after 3 sessions), Week 6 (post-intervention, after session 18)]
• Cognitive Function:Operation Span Test Task [Time frame: Baseline (Week 0),Week 1 (after 3 sessions), Week 6 (post-intervention, after session 18)]
• Cognitive Function: The Trail Making Test [Time frame: Baseline (Week 0), Week 1 (after 3 sessions), Week 6 (post-intervention, after session 18)]
• Cerebral Oxygenation - Oxyhemoglobin (O₂Hb) [Time frame: Baseline (Week 0), Week 1 (after 3 sessions), Week 6 (post-intervention, after session 18)]
• Cerebral Oxygenation - Deoxyhemoglobin (HHb) [Time frame: Baseline (Week 0), Week 1 (after 3 sessions), Week 6 (post-intervention, after session 18)]

Secondary outcome measures (1)

• Autonomy and Daily Functioning (Activities of Daily Living Scale) [Time frame: Baseline, and post-intervention (week 6, session 18)]

Eligibility criteria

• Inclusion Criteria:

• Adults aged 50 to 65 years (male and female)
• Montreal Cognitive Assessment (MoCA) score ≥ 24
• No participation in any structured exercise intervention in the last 6 months
• No exposure to altitudes above 1,500 m in the preceding 3 months
• No chronic kidney, cardiovascular, metabolic, neurological, or orthopedic -disease
• No history of significant respiratory conditions (e.g., asthma, exercise-induced -bronchospasm, dyspnea on exertion)
• No current immunosuppressive treatment (e.g., corticosteroids, antidepressants)
• No history of cancer or arthritis treatments
• No recent blood donation (within the last 2 months)
• Must be covered by a Social Security system or equivalent
• Signed informed consent after receiving clear and transparent study information
• Eligibility confirmed by a medical doctor during the inclusion process
• Exclusion Criteria:

• Active smoking
• Major cardiovascular complications within the last 3 months (e.g., myocardial i-infarction, unstable angina, severe arrhythmias)
• Severe hypertension (≥180 mmHg systolic or ≥110 mmHg diastolic)
• Chronic respiratory insufficiency (e.g., COPD, sleep apnea)
• Diabetes mellitus
• Need for continuous or intermittent oxygen therapy
• Participation in another clinical study at the same time
• Use of corticosteroids or other systemic immunosuppressants
• Any condition compromising safety or study compliance, as determined by the medical team
• Pregnancy or breastfeeding
• Legal or administrative protections (e.g., individuals under guardianship, persons deprived of liberty)
• High baseline physical activity levels (PASE score >90 indicating moderate-to-intense physical activity)

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Prevention

Study locations

Center list to be confirmed — check the primary protocol.

Publications

• Schega L, Peter B, Brigadski T, Lessmann V, Isermann B, Hamacher D, Torpel A. Effect of intermittent normobaric hypoxia on aerobic capacity and cognitive function in older people. J Sci Med Sport. 2016 Nov;19(11):941-945. doi: 10.1016/j.jsams.2016.02.012. Epub 2016 Apr 26. PMID 27134133
• Boulares A, Pichon A, Faucher C, Bragazzi NL, Dupuy O. Effects of Intermittent Hypoxia Protocols on Cognitive Performance and Brain Health in Older Adults Across Cognitive States: A Systematic Literature Review. J Alzheimers Dis. 2024;101(1):13-30. doi: 10.3233/JAD-240711. PMID 39093075
• Schega L, Peter B, Torpel A, Mutschler H, Isermann B, Hamacher D. Effects of intermittent hypoxia on cognitive performance and quality of life in elderly adults: a pilot study. Gerontology. 2013;59(4):316-23. doi: 10.1159/000350927. Epub 2013 May 3. PMID 23652274

Identifiers

NCT: NCT06874387 · HYPOX-AGE-2024-A00894-43

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗