Low water intake usually goes unnoticed, but it can change the functioning of the entire body even before thirst appears. The kidneys are responsible for filtering the blood and getting rid of toxic substances, which is why they are the first to sense when the body becomes dehydrated.
Even mild dehydration takes a toll on the mind and body. In the mind, concentration decreases and memory is affected. In the body, exercise performance decreases, blood pressure drops, and body temperature can rise, which can lead to heat exhaustion.
All this happens because the body enters “water saving mode”, which leads to increased load on the kidneys, which need to intensify the reabsorption of fluid to maintain vital functions.
The main signs of dehydration
Persistent dehydration causes non-specific symptoms, which means that many people do not associate it with a lack of water. Experts he consulted Capitals List the main signs that may appear in daily life:
- Constant fatigue: It arises due to lack of tissue irrigation and low oxygen to the brain and muscles.
- Frequent headaches: Decreased circulating blood volume makes the body work at a slower pace, leading to bouts of pain.
- Dizziness when standing: The body has difficulty stabilizing blood pressure when fluid volume is low.
- Dark or strong-smelling urine: The concentration increases because the kidneys try to retain water, making the urine darker and denser.
- Decreased urine volume throughout the day: The body slows urine production to conserve fluids and protect essential functions.
How does the body react when exposed to dehydration?
Dehydration causes the body to activate some methods of compensation. To try to store the remaining water, the body starts processes that make everything more economical: the release of hormones that carry the fluid increases, the volume filtered by the kidneys as well as the blood circulation decreases.
Combined, these mechanisms make urine dark and concentrated, which is one of the first signs that the body is on alert. Over time, this extra effort becomes exhausting.
Kidney cells are exposed to a denser, less irrigated environment, a situation that causes a temporary decline in kidney function and facilitates cumulative damage in people who experience repeated periods of dehydration.
“Even a small decrease in the volume of available water already changes the way the kidney filters the blood, because it begins to receive a slower, more concentrated flow. This scenario forces the kidney structures to work at maximum capacity to maintain the body’s balance,” explains Pedro Mendes Filho, a nephrologist at Brasilia Hospital.
Who is most at risk of dehydration?
Not everyone feels thirsty the same way. Children and the elderly tend to be less aware of water shortages and often rely on other people to maintain sufficient water.
Those who work in hot weather, spend hours in air conditioning or do intense exercise also lose fluids quickly. There are still some daily habits that make the situation worse.
Excessive consumption of coffee, stimulant tea, alcoholic beverages, and the use of diuretics increases the elimination of water and makes the body release it more easily.
“In older people, for example, the perception of thirst is lower, which causes the body to remain in a state of deficit for long periods without the person noticing,” says nephrologist Philip Kruger, of the São Lucas Hospital in Rio de Janeiro.
Possible kidney complications due to dehydration
A lack of water changes the environment of the kidneys and makes everything more vulnerable to problems. Highly concentrated urine facilitates the formation of crystals, which can clump together and develop into kidney stones.
Furthermore, decreased water flow compromises the natural cleaning of the urinary tract, allowing bacteria to settle more easily and cause infections.
Over the years, these attacks accumulate and increase the risk of developing chronic kidney disease, a condition characterized by a slow, gradual, and irreversible loss of the kidneys’ ability to function.
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