Actively Recruiting
BRAHMS: Bed Rest And HypoMetabolism Study
Led by Centre National d'Etudes Spatiales · Updated on 2026-03-30
10
Participants Needed
1
Research Sites
80 weeks
Total Duration
On this page
Sponsors
C
Centre National d'Etudes Spatiales
Lead Sponsor
M
MEDES Institut de Médecine et de Physiologie Spatiales, Toulouse
Collaborating Sponsor
AI-Summary
What this Trial Is About
The goal of this single arm, interventional monocentric clinical trial is to investigate the physiological effects of a combination of head-down bedrest and caloric restriction on the human body. A set of measurements will assess the changes in the musculoskeletal, cardiovascular, hematological, immune, neurological, cognitive and metabolic systems, in 10 healthy male volunteers. The main question it aims to answer is: what are the physiological responses to fasting in a microgravity environment? In an exploratory study such as this one, where many physiological systems are explored, it is difficult to select a single important endpoint. However, given the known effect of both caloric restriction and head-down bedrest on muscle loss, and its critical importance for the success of space missions, lean body mass, as assessed by DEXA, was chosen as the primary endpoint. The secondary endpoints are: * Cardiovascular, muscular, neuro-vestibular and neuropsychological functional performance * The onset of clinical symptoms and biological changes Participants will be exposed to a microgravity analog model (head down bed rest) and controled caloric restriction environment for 10 days, multiple physiological assessments will be performed during this period. Followed by a rehab period before leaving the study.
CONDITIONS
Official Title
BRAHMS: Bed Rest And HypoMetabolism Study
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Healthy male volunteers aged 20 to 40 years
- Height between 165 and 185 cm
- Body Mass Index between 20 and 26 kg/m2
- Stable body weight with less than 4% change in the past 3 months
- Fat Mass Index between 3 and 6 kg/m2 measured by whole-body DEXA
- Triglyceride level under 1.7 mmol/L
- Normal bone mass density at left hip and lumbar spine with T-score > -1.5 measured by DEXA
- VO2peak/VO2max between 35 and 55 mL/min/kg
- Non-smokers
- No alcohol or drug dependence and no regular medical treatment
- Affiliated to a Social Security system or holding a European or Global Health Insurance Card
- Free of any engagement during the study
- Provided informed consent
You will not qualify if you...
- History or presence of clinically relevant chronic or acute infectious diseases
- Symptomatic or asymptomatic orthostatic hypotension
- Personal or family history of thrombosis or genetic mutations for factor V or prothrombin gene
- Cardiac arrhythmia or hypertension
- Autoimmune diseases or Raynaud's syndrome
- History or symptoms of sleep apnea
- Chronic back pain, vertebral fracture, scoliosis, or herniated disc
- Color blindness or hearing problems
- Vestibular disorders
- Drug addiction
- History of migraines, hiatus hernia, or gastro-esophageal reflux
- History of thyroid dysfunction or diabetes
- History of head trauma or neurological diseases such as epilepsy
- Genetic muscle and bone diseases
- Significant allergy history
- Abnormal blood test results
- Positive serology for hepatitis A, B, C, or HIV
- Current or past mood or eating disorders
- Antibiotic exposure in the 2 months prior to the study
- Major lifestyle changes in the 6 months prior to the study
- Specific diets such as vegan, carnivore, intermittent fasting, or dietary supplements use
- History of significant hypocaloric diet
- Potential non-compliance or inability to cooperate
- Participation in another clinical research exclusion period
- Receipt of 6000 Euros or more for research participation in the past 12 months
- Poor tolerance to blood sampling
- Inability to be contacted in emergency
- MRI contraindications such as claustrophobia or metal implants
- Blood donation exceeding 7 ml/kg in the 8 weeks before the study
- Vulnerable persons including pregnant or nursing women, minors, people deprived of liberty, under involuntary psychiatric care, or legally protected adults
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Trial Site Locations
Total: 1 location
1
Medes - Imps
Toulouse, Medes-imps, France, 31400
Actively Recruiting
Research Team
M
Marie-Pierre Bareille
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
OTHER
Number of Arms
1
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