Fig 1.
Illustration of the experimental protocol.
The subject will participate in two experimental conditions. In randomized order, the subject will participate in one condition including lower body negative pressure (LBNP) 60 mmHg for six minutes and another experimental condition with both LBNP 60 mmHg for six minutes and thigh cuff inflation for the last three minutes.
Table 1.
Eligibility criteria for the study population.
Fig 2.
Illustration showing the subject with thigh cuffs inside the LBNP chamber.
1) The lower body negative pressure (LBNP) chamber is 2) sealed just above the iliac crest and connected to 3) a vacuum pump controlled by 4) a pressure control unit. The applied negative pressure is displayed on 5) a pressure monitor. 6) Thigh cuffs are positioned proximal on both thighs, inflated by 7) Venopulse. 8) The pulse oximeter is positioned at the first toe on the left foot, ensuring complete occlusion to the lower limbs. Measuring 9) ascending aortic blood velocity by suprasternal pulsed Doppler ultrasound, 10) ECG, 11) mean arterial pressure (MAP) on 12) a data acquisition device, 13) sampled continuously on a laptop. 14) Cerebral tissue oxygen saturation (ScO2) will be measured by near-infrared spectroscopy sampled on 15) an Invos monitor. 16) Mean cerebral artery velocity is sampled by a 1-5 MHz M5S probe connected to 17) Triplex transcranial Doppler ultrasound.