This study is an open crossover study. The study group will consist of healthy volunteers who are wearing patches over 8 days.~Purpose of study The purpose of the study is to test the ability of a new electronic patch to detect moderate dehydration and re-hydration by changes in bioimpedance spectroscopy (BIS). In addition, the researchers will study changes in bioimpedance related to normal variation in tissue hydration circadian changes, skin thickness, posture, and moderate activity).~The primary endpoint is the detection of the dehydrated state after intervention A or B.~The secondary endpoints are:~detection a re-hydrated state after mild dehydration. detection of any significant differences between the two dehydration interventions description of the circadian changes of normal healthy volunteers Hypothesis: The patch can detect a BIS change in local fluid volume in case of moderate dehydration correlated to reference points for fluid loss (blood samples, diuresis, weight loss, self-experience of thirst). Secondary hypothesis: The patch can detect a BIS change in local fluid volume after rehydration from moderate dehydration correlated to reference points for fluid loss (blood samples, diuresis, weight gain, self-experience of thirst).~Tertiary hypothesis: The patch can detect a significant difference in BIS between the two intervention methods (pharmacologic and physical exercise).~Practical implementation The study is conducted by bringing healthy volunteers to a normal volume, isotonic state through intake of water and logging of food and liquid intake (including alcohol), physical activity, drug intake and number of days since the first day of the last menstrual cycle.~The subject undergoes a clinical examination, including weighing and measuring and an assessment of skin thickness as well as blood samples.~The position for placement of the patch is marked with a marker and photographed. then the patches are mounted in accordance with the description in the Instructions for Use (IFU). One patch is placed on the back, one under the arm pit and one on the leg.~The subjects will carry the patches for eight days. The patch on the back will be replaced by a new patch after the first intervention. The other two patches will stay on throughout the eight days.~The subjects are exposed to two different interventions (A and B) while being monitored by health personnel:~A: one physical exercise on a bicycle for 60 minutes at 80 of max heart rate (HR), leading to a loss of more than 1.5% of body weight. The subjects are monitored for an additional two hours.~B: one where the subjects are given a diuretic (Furosemide) and monitored for three hours without any intake.~- both interventions are followed by controlled intake of liquid intake two hours into the intervention, the liquid containing glucose and electrolytes (Resorb Sport, Nestle S.A.).~All subjects will carry out both interventions, but on two different days. There must be a minimum of 24 hours between two interventions. The subject must consume 500 ml of water two hours prior to starting either of the two controlled interventions. The purpose of fluid intake is to correct any existing dehydration, while giving the body time to expel excess fluid and to reach the desired normal degree of hydration.
A new electronic patch has been developed that makes non-invasive measurements of bioimpedance in underlying tissues. The purpose of this study is to map the patch's ability to detect specific changes in hydration status in moderate hypovolemia with the device. In addition, the researchers want to record normal variation (diurnal variation and variation related to factors such as body position and body temperature) in bioimpedance in healthy volunteers