This article will primarily cover the physiologic composition of water in the human body, differentiate the various compartments in the body and their associated volumes and compositions, depict how to measure the different volumes, and delve into the clinical relevance associated with disturbances of the normal physiological conditions. However, various clinical pathologies can alter the fluid composition and its constituents in the multiple compartments of the human body, which can have deleterious effects on our health and often require intensive interventions to monitor and maintain normal physiological conditions. As the distribution of the fluid in the body and the substances found within is critical for the maintenance of intracellular and extracellular functions pivotal to survival, the body has developed mechanisms to control compartment composition tightly. Examples of proteins include coagulation factors, immunoglobulins, albumin, and various hormones. A third important group of substances contained within the water of our body, which includes proteins, most of which are vital for our existence. Another group includes metabolites, such as oxygen, carbon dioxide, glucose, urea, etc. One such group of substances includes electrolytes such as sodium, potassium, magnesium, phosphate, chloride, etc. At the end of the starvation period, BMI (21.5+/-2.6 kg/m2) and most anthropometric determinations were still acceptable, suggesting efficient energy and muscle conservation.ġ) All compartments diminished during fasting, but body fat was by far the most affected 2) Total water was low and total body resistance comparatively elevated, but these findings rapidly reversed upon rehydration 3) Exaggerated fat percentage estimates from BIA tests and simultaneous increase in lean body mass estimates suggested that this method was inappropriate for assessing energy compartments in the studied population 4) Patients were not morphologically malnourished after 43 days of fasting however, the prognostic impact of other impairments was not considered in this analysis.The fluids of the body are primarily composed of water, which in turn contains a multitude of substances.
Water was comparatively low with high total resistance, and these findings rapidly reversed upon the intravenous rapid hydration.
TSF findings were much lower and commensurate with other anthropometric results. Initial fat was estimated by BIA as 52.2+/-5.4% of body weight, and even on the 43rd day it was still measured as 19.7+/-3.8% of weight. Body fat decreased approximately 60% (BIA and TSF), whereas BMI reduced only 18%. On the last two days of the fast (43rd-44th day) rapid intravenous fluid, electrolyte, and vitamin replenishment were provided before proceeding with realimentation. Only water, intermittent vitamins and electrolytes were ingested, and average weight loss reached 17.9%. The age of the group was 43.3+/-6.2 years (seven males, one female). Indirect calorimetry was also performed in one occasion. Measurements included body mass index (BMI), triceps skinfold (TSF), arm muscle circumference (AMC), and bioimpedance (BIA) determinations of water, fat, lean body mass (LBM), and total resistance. In a group of eight hunger strikers who refused alimentation for 43 days, water and energy compartments were estimated, aiming to assess the impact of progressive starvation.
Prolonged total food deprivation in non-obese adults is rare, and few studies have documented body composition changes in this setting.