Dehydration: symptoms, causes and remedies

Introduction

Water in the Human Body

The quantity of water present in the human organism reaches very high values, so as to constitute between 50 and 80% of the body weight ; these two extremes concern, respectively, the elderly and children, while in adults the water levels are around 60% of body weight (they are slightly higher in men and in athletes, while they are slightly lower in women and in obese people ).
Water, therefore, is the most important constituent of our body and it is known that without its contribution from the outside we can only survive for a few days.

Things

Dehydration: What is it?

Dehydration is the lack of water in the body, a lack which may be due to an insufficient intake in the diet and/or excessive losses ( profuse sweating and diarrhea , repeated vomiting , burns , bedsores , polypnoea, taking diuretics , laxatives or particularly low-salt water , a high-protein diet , diabetes mellitus , diabetes insipidus , heavy salt consumption ).

Dehydration becomes morbid when loss exceeds 5-6% of body weight.

In basal physiological conditions (at rest) and at room temperature (18-20°), water losses are less than 1 ml/min .
With physical activity and the increase in external temperature, these losses, mainly due to sweating, can reach 15-25 ml/min .

Although the body is capable of limiting – even considerably – water losses, we must never forget the importance of water in human nutrition . It is not uncommon for people to combine a reduced intake of liquids with a diet low in vegetables (consisting of about 90% water) and rich in dehydrating drinks (coffee, spirits, cola, etc.), with inevitable suffering from whole organism.

Body water is present in three different compartments :

Intracellular : it represents 40-50% of the body weight and is very important for the normal development of the metabolic processes of the cells ;
Intravascular : represents 7% of body weight and is the main component of blood plasma ;
Extracellular : it constitutes 17-20% of body weight, is found in the spaces between one cell and another and allows the exchange of substances between the blood in the capillaries and the cells.

Types

Types of Dehydration

Three types of dehydration can be distinguished: hypertonic, isotonic and hypotonic.

Hypertonic dehydration

Hypertonic dehydration is characterized by elevated plasma sodium levels ( > 145 mmol/L) and hyperosmolarity; it is the typical consequence of profuse sweating and the consequent drop in plasmatic volume (loss of excess water on sodium, because sweat is hypotonic , as we will see better later).

Isotonic dehydration

Usually, isotonic dehydration follows vomiting or diarrhea (loss of water and electrolytes , especially sodium, in balanced proportions).

Hypotonic dehydration

Hypotonic dehydration is characterized by a decrease in plasma sodium levels ( hyponatremia ) and a reduction in osmolarity ;
Hypotonic dehydration is the typical consequence of the abuse of diuretics or of rehydration with low-sodium waters (be careful, in summer, associating low-sodium diets with the consumption of low fixed residue waters can be dangerous: salt is not an absolute enemy; a moderate intake of it is correct, but not its complete abstinence).
It is no coincidence, therefore, that many people report that they are still thirsty despite drinking a lot of low-salt water.

Symptoms