You've all heard of dehydration, but do you really know its consequences? Do you know how to recognize the effects of dehydration on your body? We're going to learn more about it in this article!
It's true that we often feel thirsty, but it's important to hydrate before it appears, because it's already a sign of dehydration! Moreover, this feeling may not appear at all or may disappear after a while. It's therefore possible to forget to hydrate, in which case, dehydration is likely to worsen. This is why it's essential to ensure that children and elderly people are well hydrated, especially in summer.
The first symptoms are generally discreet: headaches, fatigue, dizziness, and confusion. We sometimes realize we have a headache after a long day when we haven't hydrated, and these sensations pass when we rehydrate.
The evolution of the weight curve is very important. Indeed, weight loss is one of the dehydration indicators to take into account:
- Mild dehydration, corresponding to a loss of 1 to 2% of body weight, leads to a decrease in physical and cognitive performance ranging from 10 to 20%. Fatigue then gradually sets in, and a feeling of thirst may appear, although it is sometimes absent. Physical signs such as dry mucous membranes, dark circles under the eyes, and cold extremities may be observed.
- Moderate dehydration, corresponding to a loss of 2 to 4% of body weight, manifests as more marked fatigue and decreased vigilance. Heart rate increases to compensate for the reduction in blood volume, leading to tachycardia. The sensation of a dry mouth intensifies, the skin becomes duller, and a transient skin fold may appear when lightly pinched.
- Severe dehydration, corresponding to a loss of 5 to 8% of body weight, causes disturbances of consciousness ranging from disorientation to confusion. The decrease in blood volume leads to hypotension and an increased risk of serious accidents, such as discomfort or a fall. The skin becomes dry, skin folds persist, cheeks become hollow, and urine production decreases sharply (oliguria).
When fluid loss reaches 8% or more of body weight, the situation becomes critical and represents a clinically severe case. The risk of coma is high, organs begin to malfunction, and limbs become cold down to the root, which is a sign of imminent circulatory shock.
What is dehydration?
Dehydration is the result of excessive loss of water and mineral salts not compensated by fluid intake. Water is essential for many bodily functions, so its lack causes the effects discussed above.
There are several types of dehydration: extracellular dehydration, intracellular dehydration, and global (or chronic) dehydration. There are common effects to these dehydrations and more specific signs allowing them to be distinguished.
Whatever its form, dehydration should never be taken lightly. Insufficient hydration can quickly affect vital functions and endanger your health.
Most frequent causes of dehydration
Dehydration can have multiple origins, and its causes are often similar.
First, there are renal losses. These can be due to excessive diuresis (volume of urine evacuated in 24 hours), which is found, for example, in the case of diabetes. Certain kidney failures or the use of diuretics can also lead to significant fluid loss.
Digestive losses are also a common cause of dehydration that must be remedied quickly. Prolonged diarrhea and vomiting lead to a rapid loss of water and electrolytes, which can lead to severe dehydration if fluid intake is not quickly compensated.
Cutaneous losses are often underestimated. However, excessive sweating during physical activity or in hot weather is a major cause of dehydration. Fever and heatstroke also increase fluid loss.
Pulmonary losses, although less visible, can contribute to dehydration, as a quantity of water is evacuated in the form of vapor. This phenomenon is accentuated in cases of hyperventilation, particularly during sports practice, contributing to body water loss.
Other external factors can play a role in dehydration, and excessive alcohol consumption is a very good example. Indeed, alcohol decreases the effectiveness of the kidneys, which increases the frequency of urination to compensate.
What are the symptoms of dehydration?
Dehydration can affect different parts of the body, leading to various symptoms depending on whether it is extracellular or intracellular.
Symptoms of extracellular dehydration
What is it? Extracellular dehydration results from a loss of water at the extracellular level (plasma and interstitial fluid). While intracellular water volume remains identical, an effective extracellular osmotic pressure is maintained.
Extracellular dehydration initially manifests as significant fatigue, lack of appetite, and absence of thirst, which can delay fluid intake and worsen the situation. Unlike intracellular dehydration, mucous membranes remain moist, but a slight weight loss may be observed due to decreased plasma volume.
Clinical examination reveals flat peripheral and jugular veins, as well as cold and discolored extremities, indicating low central venous pressure. Hypotension occurs, causing dizziness and an accelerated pulse to maintain adequate organ perfusion. Skin turgor is altered, with a persistent skin fold, particularly in the abdomen, supraclavicular region, and inner thighs (this sign can, however, be difficult to interpret in elderly people).
The eyeballs appear sunken, a sign of some fluid deficit. In cases of severe extracellular dehydration, the clinical condition worsens with very low blood pressure (below 80 mmHg), cold extremities, and the presence of mottling on the skin, indicating imminent shock requiring urgent medical attention.
What are the risks? Severe extracellular dehydration can lead to a significant drop in blood pressure, limiting oxygen supply to organs and causing hypovolemic shock. Kidneys, lacking water, greatly reduce urine production or risk acute kidney failure. Without rapid management, these complications can be life-threatening. So, we advise you to make an appointment with a healthcare professional quickly!
Symptoms of intracellular dehydration
Intracellular dehydration occurs when the intracellular compartment becomes dehydrated due to an increase in plasma osmolarity (generally an excessive concentration of sodium in the blood) that the body has compensated for by sending water from the intracellular compartment into the plasma to dilute the excess sodium and thus restore fluid balance. This loss of intracellular water leads to cell contraction, particularly affecting those of the brain and muscles.
One of the first signs of intracellular dehydration is intense and uncontrollable thirst, as the body desperately tries to compensate for the fluid deficit. As the situation worsens, disturbances of consciousness appear, ranging from confusion to a deep coma in the most extreme cases.
Weight loss can be significant, reaching up to 20% of body weight, a sign of severe fluid deficit. This dehydration is often accompanied by fever and a high respiratory rate that aggravates water loss.
Other signs can help identify this form of dehydration. Mucous membranes are dry, and the tongue is retracted. A medical examination can also reveal neurological disorders, a direct consequence of the shrinking of brain cells.
What are the risks? Severe intracellular dehydration can have serious effects, especially on the brain. When cells lose too much water, they shrink, which can lead to memory problems, difficulty concentrating, and confusion. In the most serious cases, this can lead to loss of consciousness or a coma.
In infants and elderly people, the brain is more fragile, and this dehydration can sometimes cause a small cerebral hemorrhage (subdural hematoma). If it lasts too long, it can leave lasting effects on intellectual and motor abilities.
How to treat dehydration?
Adult, child, infant, different treatment?
To rehydrate, the principle is the same for everyone: drink to regain lost water and restore electrolyte balance. However, the method of administration and management vary according to age and the severity of dehydration.
For an infant, for example, oral rehydration solutions (ORS) are necessary. These solutions, specifically designed to compensate for fluid and electrolyte losses, are the best option because babies have difficulty expressing their thirst and cannot regulate their own hydration.
For an older child, rehydration can be done via ORS, but also through food with electrolyte-rich foods such as salt (sodium) or banana (potassium). However, it can be difficult to get them to drink a large amount of water. If dehydration is mild to moderate, encouraging them to drink small amounts frequently is an effective approach. If the child refuses to drink plain water, alternatives such as slightly sweetened and salted drinks, broths, or water-rich fruits (watermelon, cucumber, etc.) can be used.
For an adult, all methods are suitable, and it is easier for them to assess their condition and monitor their water intake. However, severe dehydration should not be overlooked, as it may require urgent medical attention!
What are the solutions?
Severe cases and intravenous solution
If severe dehydration occurs, consulting a doctor or going to the hospital is essential. In terms of care, there are several possibilities to treat the patient: first, direct control of the amount to drink. Indeed, it is necessary to have controlled oral rehydration, under medical supervision to avoid any osmotic imbalance.
Then, in the worst cases (repeated vomiting, consciousness disorders, hypovolemic shock, etc.), it is possible to resort to intravenous administration of a sodium chloride solution.
ORS
ORS are the reference for treating mild to moderate dehydration, particularly in infants and young children. Recommended by the WHO, they allow rapid absorption of water and electrolytes through the combination of sodium and glucose. They are particularly effective in cases of diarrhea, gastroenteritis, or fever, when the child loses a significant amount of fluid.
In adults, rehydration relies more on regular water consumption, including drinks containing sodium, potassium, and glucose to improve intestinal absorption of water and fluid retention. There are several solutions, from the most basic, such as sugary and salty water, to solutions that optimize effects on the body with other supplements, such as trace elements, as Hydratis does.
Why use Hydratis?
Hydratis is a hydration solution composed of sugars, electrolytes, and trace elements, designed to improve hydration in cases of fatigue, intense physical exertion, hot weather, or athletic recovery. It is based on WHO recommendations and suitable for most people.
Its convenient format and various flavors, to suit everyone, make it a pleasant alternative to traditional solutions, while offering rapid and targeted hydration.
5. Some tips to prevent dehydration
To prevent dehydration, there are two main conditions to respect:
First, ensure you maintain a good electrolyte balance. This can be done simply with a varied diet or ORS.
Then, you obviously need to drink enough water, beyond just listening to the sensation of thirst. This is particularly important for vulnerable people (young children who may have difficulty judging their condition or quenching their thirst themselves, and older adults for whom the effects of dehydration are amplified) and for athletes, who lose water much faster through sweat and exhalation. ORS such as Hydratis are ideal then, also offering various flavors. If you want to use tap or bottled water, ANSES provides an effective infographic to remember the most important points.
Bibliography
Bottled water or tap water: good consumption practices - ANSES
Adrogue, H. J., & Madias, N. E. (2000). "Hypernatremia". New England Journal of Medicine, 342(20), 1493-1499. https://pubmed.ncbi.nlm.nih.gov/10816188/
Hew-Butler, T., Rosner, M. H., Fowkes-Godek, S., et al. (2008). "Exercise-Associated Hyponatremia: Consensus Guidelines". Clinical Journal of Sport Medicine, 18(2), 111-120. https://pubmed.ncbi.nlm.nih.gov/26102445/
Cheuvront, S. N., Kenefick, R. W., & Sawka, M. N. (2010). "High Sweat Sodium Losses: A Risk Factor for Cramping and Hyponatremia?". Journal of Athletic Training, 45 (1), 25-30. https://pmc.ncbi.nlm.nih.gov/articles/PMC9699060/
Sawka, M. N., Cheuvront, S. N., & Kenefick, R. W. (2015). "Hypohydration and Human Performance: Impact of Environment and Physiological Mechanisms". Sports Medicine, 45 (S1), 51-60. https://pubmed.ncbi.nlm.nih.gov/26553489/
