A Comparison Study Between 10 Days of Dry Immersion Versus 10 Days of Head-down Bedrest on 20 Healthy Male Volunteers

Exclusion Criteria

• •Any history or presence of clinically relevant cardiovascular, neurological or ENT (especially orthostatic hypotension and vestibular disorders), any chronic disease; any acute infectious disease. Particularly:
• •Symptomatic orthostatic hypotension whatever the decrease in blood pressure, or asymptomatic postural hypotension defined by a decrease in SBP equal to or greater than 20 mmHg within 3 minutes when changing from the supine to the standing position,
• •Cardiac rhythm disorders,
• •Hypertension,
• •Chronic back pains,
• •Vertebral fracture, scoliosis or herniated disc,
• •Glaucoma,
• •Self-reported hearing problems,
• •History of migraines,
• •History of hiatus hernia or gastro-esophageal reflux,
• •History of thyroid dysfunction, renal stones, diabetes,
• •History of head trauma,
• •History of genetic muscle and bone diseases of any kind,
• •Past records of thrombophlebitis, family history of thrombosis or positive response in thrombosis screening procedure (anti thrombin III, S-protein, C-protein, factor V Leiden mutation and the mutation 20210 of the prothrombin gene),
• •Signs of venous insufficiency, varicose veins, or telangiectasia
• •Bone mineral density: T-score ≤ -1.5,
• •Poor tolerance to blood sampling,
• •Having given whole blood (more than 7ml/kg) in a period of 8 weeks or less before the start of the experiment, or having given whole blood more than 5 times in the past 12 months,
• •Significant history of allergy, especially no dermatological allergy,
• •History of food allergy,
• •Significant anomaly detected in the biological analysis,
• •Positive reaction to any of the following tests: HVA IgM (hepatitis A), HBs antigen (hepatitis B), anti-HVC antibodies (hepatitis C), anti-HIV1+2 antibodies,
• •Vegetarian or vegan,
• •Refusal to give permission to contact his general practitioner,
• •Subject who, in the judgment of the investigator, is likely to be non-compliant during the study, or unable to cooperate because of a language problem or poor mental development,
• •Subject already participating or in the exclusion period of a clinical research,
• •Subject who has received more than 6000 Euros within 12 months for being a research subject,
• •MRI contraindications:
• •History or active claustrophobia,
• •Osteosynthesis material, presence of metallic implants or any other contra-indication for MRI,
• •Allergy to Gadolinium.
• •Vulnerable persons according to law "Code de la Santé Publique" (L1121-5 to L1121-8) :
• •Persons deprived of their liberty by an administrative or judicial decision,
• •Persons under involuntary psychiatric care,
• •Persons admitted in a health or social establishment for purposes other than research,
• •Minors,
• •Adults subject to legal protection (subject under guardianship or trusteeship) or unable to express their consent.