The Effect of Potassium Bicarbonate on Bone and Several Physiological Systems During Immobilisation

Inclusion Criteria: * healthy male subjects * age: 20- 45 * weight 65- 85 kg * height: 158- 190 cm * BMI 20- 26 kg/m2 * no high performance sports * non- smoking (minimum 6 months prior to study start) * willing to complete both parts of the study * presentation of social security and criminal record * successful completion of medical and psychological screening * signed informed consent Exclusion Criteria: * drugs- and alcohol abuse * antiinflammatory drugs taken during the study * vegetarianism, veganism * migraine * psychical illness in the past * claustrophobia * hiatal hernia * gastroesophageal reflux * diabetes mellitus * Rheumatic disease * muscle or joint disease * disc prolapse * orthostatic intolerance * Hyperlipidaemia * renal disease * thyroid dysfunction * hyperhomocysteinaemia * hyper-/hypouremia * hyper-/hypocalcemia * anaemia * hypoferremia * Vitamin D deficiency * deviation of blood gases from normal values (pH 7,38 - 7,42; pO2 79 - 98 mmHg; pCO2 34 - 45 mmHg; HCO3 20 - 28 mmol/l; Base excess ± 2 mmol/l) * risk of thrombosis * chronic back pain * bone fracture within one year prior to study start * bone mineral density 1,5 SD ≤ t-Score * metal implants or other osteosynthesis material * subject within another clinical trial within 2 months prior to study start * any other status which according to the apprehension of the principal investigator leads to the exclusion of the subject