The aim of this pilot was to study how body water behaves between the different internal water pools of the human body, what the role and influence of the interstitium is and what the effect is of body position on the distribution and allocation of BW between different body parts (trunk, legs, arms). To study this, 2 techniques that have not been used before in urological research were tested on their usefulness:

• The first technique is a recent BIA device, which distinguishes itself from earlier devices by measuring impedance at different electrical currencies in different body parts (arm/limb/trunk). This technique made it possible to observe the influence of body position on the distribution of BW in these body compartments. Rationale for this research question is mainly the link between NP and edema that was found in earlier research and the fact that body position seemed to have an impact on the size of edema. For this reason, it can be suggested that body position and thus edema will have an impact on whether or not NP occurs.
• The second technique uses deuterium as a biological marker. With this technique the distribution, storage, allocation and excretion of BW was examined among the urological most relevant water pools (blood, urine and interstitium).

Inclusion Criteria:

• Healthy individuals
• Ages between 18 and 30
• BMI between 18 and 24.9

Exclusion Criteria:

• Intake of medications except of OAC
• Patients with pacemaker or neurostimulator