 Study participants Recruiting was based on voluntary registration in response to a public announcement. The study was subjected to the local ethical committee review No. 23-321 ex 1011 and all persons gave written informed consent according to the Helsinki Declaration. Key lifestyle and medical parameters were documented for every subject. Exclusion criteria were pregnancy, latex and polyvinyl chloride allergy, claustrophobia, hypotension, history of vein thrombosis, chronic obstructive pulmonary disease, epilepsy, cardiovascular and pulmonary diseases, and infectious diseases. Ten male and nine female volunteers were recruited, aged between 21 and 38 years with body-mass-indices from 17.2 to 32.5. 