Why does the body need water?
Water is a key element without which the body cannot exist. It helps regulate body temperature, helps deliver nutrients to cells, and removes metabolic waste. Lack of water slows down blood circulation, impairs brain function, and can cause serious health problems.
What happens in the body when there is a lack of fluid :
- Biochemical reactions slow down. The breakdown of carbohydrates, energy production, protein synthesis and many other processes in the body occur in an aqueous environment. Liquid deficiency inevitably reduces energy levels and slows down tissue regeneration.
- Digestive processes are disrupted. Gastric juice consists of more than 90% water, without which it is impossible to properly digest food. Lack of fluid leads to constipation and other gastrointestinal tract disorders.
- The properties of blood change. Water deficiency makes blood more viscous, increasing the risk of blood clots and cardiovascular diseases.
- Thermoregulation is disrupted. With a water deficit, the body cannot cool itself effectively, as sweating, the main mechanism of thermoregulation, decreases.
- Joints suffer. Due to lack of water, the volume of synovial fluid, which acts as a natural lubricant in the joints, decreases. This increases friction between the joint surfaces, reduces cushioning, and increases the risk of inflammation. With a lack of water, cartilage tissue wears out faster, and over time, the likelihood of arthrosis and other joint diseases increases.
In addition, with a lack of water, the skin becomes dry, and hair becomes brittle and dull. Due to a lack of moisture, nails can exfoliate and become covered with longitudinal grooves.
Why does dehydration occur?
Dehydration is a condition in which the body uses more water than it receives. Fluid deficiency can develop for various reasons, such as increased sweating, illness, or taking certain medications.
The body of a healthy adult consists of 55–78% water. Dehydration begins when 1–2% of fluid is lost. When 5% of water is lost, a person becomes dizzy, the heart beats faster, and weakness appears. If more than 10% of fluid is lost, the functioning of internal organs is seriously disrupted, a person may lose consciousness, and there is a threat to life.
The main causes of dehydration:
- not enough water in the diet;
- intense sweating in hot weather, during physical exertion, high body temperature;
- taking diuretics;
- vomiting, diarrhea;
- diabetes mellitus;
- kidney disease;
- some hormonal disorders (hyperthyroidism, Addison’s disease).
Dehydration can occur in anyone, but some people are more susceptible to the condition.
Who is more likely to experience dehydration:
- infants and children under three years of age;
- elderly people;
- athletes;
- people who work in the heat (construction workers, road workers, farmers);
- pregnant and lactating women;
- people who abuse alcohol, caffeine.
How to recognize dehydration
It is believed that the main sign of dehydration is thirst. But it does not always appear. Thus, in older people, the sensitivity of the receptors responsible for perceiving the level of fluid in the body decreases with age, so they may not feel thirsty for a long time.
Signs of mild to moderate dehydration:
- thirst;
- dry mouth;
- small amount of urine;
- dark colored urine;
- rare urge to urinate.
Signs of severe dehydration that require immediate medical attention:
- dizziness, especially when rising suddenly;
- pressure below 80/50 mm Hg;
- pulse over 100 beats per minute;
- confusion;
- dry, pale and cold skin;
- no urination for more than 6-8 hours;
- incoherent speech;
- convulsions.
Do you need to drink 2 liters of water per day?
“You need to drink at least two liters, or eight glasses, of water a day” – everyone has heard this advice at least once. In fact, this “norm” is not supported by scientific data.
It is difficult to say when exactly the myth about two liters of water was formed. It probably arose back in 1945 after the release of recommendations from the Food and Nutrition Board of the National Research Council of the United States [5]. In them, experts recommended drinking 1 ml of liquid for each kilocalorie consumed. This is exactly equal to 2 liters of water for an average diet of 2000 kcal.
There is no single water norm that a person should drink per day. Official recommendations from relevant agencies vary from country to country.
According to the National Academies of Sciences, Engineering, and Medicine (NASEM) :
- Men need to drink an average of 3.7 liters of water per day.
- for women – 2.7 liters.
The European Food Safety Authority (EFSA) recommends :
- 2 liters of water per day for women;
- 2.5 l – for men.
The formula “30 ml of liquid per kilogram of weight” is popular among Russian doctors. The Ministry of Health also relies on these figures.
The 2021 guidelines, which set standards for nutrient and energy requirements for Russians, state that “adequate fluid intake varies from 1 to 1.5 ml per kilocalorie, depending on the climate and level of physical activity” .
Thus, women aged 18–64 who lead a moderately active lifestyle (for example, work in an office and go to the gym or jog 2–3 times a week) are recommended to drink about 1.4–1.5 liters of water per day, while men with the same level of physical activity should drink 1.8–1.9 liters. Calculations are given for the average body mass index (BMI 20–25). People with a higher weight may require more liquid.
The Ministry of Health’s recommendations correlate with the results of a study by the University of Aberdeen, the results of which were published in the journal Science in 2022. This is the largest scientific study on water consumption in recent years: scientists and subjects from 23 countries took part in it.
Experts analyzed data from 5,600 people and found that, on average, the water norm for most adults in developed countries is 1.5–1.8 liters per day. This is how much liquid you should try to drink per day, but doctors still advise focusing on thirst: if you want to drink more, you should listen to your body.
Can you drink water while eating?
There is a common belief that drinking during meals is harmful. Supporters of this theory believe that liquid dilutes gastric juice and slows down the digestion process. In fact, water does not cause any harm to digestion. Regardless of whether we drink during meals or not, the acidity of the stomach contents and the volume of juice secreted remain approximately the same. The body is smart enough to regulate the production of gastric juice and enzymes depending on the nature and volume of incoming food and drinks.
Moreover, in moderate quantities, water during meals is even useful. It helps soften the food bolus and facilitates its digestion. It also speeds up satiety and prevents overeating. So you can drink before, after, and during meals.
You should drink plain, clean water with your food; it does not overload your stomach and does not interfere with digestion. Carbonated drinks can irritate the stomach lining and cause bloating, sweet juices contain a lot of added sugar, and alcohol and coffee interfere with the absorption of nutrients. If you want variety, you can add some lemon, mint, or berries to your water.
Which water is healthier to drink: regular or mineral water
Mineral water contains beneficial microelements (calcium, magnesium, sodium) and can be useful in certain conditions, such as mineral deficiencies.
Medicinal and medicinal-table mineral waters with high mineralization (more than 1 g of salts per liter of water) can be drunk only on the recommendation of a doctor. Excess salts overload the kidneys and cardiovascular system.
If a person likes mineral water, they can only drink it. According to the recommendations of the Ministry of Health, healthy people can drink table mineral water every day, which contains less than 1 g of salts per liter of water.
How to drink water correctly
- The main rule that will help maintain optimal water balance is to drink water regularly throughout the day, without waiting for thirst.
- The amount of water you need depends on your age, weight, activity level and climate, but on average, a healthy adult needs to drink at least 1.5 liters of fluid per day.
- Preference should be given to clean water, but it is important to remember that the body also receives fluid from vegetables, fruits, soups, and dairy products.
- It is better to drink in small portions throughout the day, rather than drinking the entire amount at once.
- It is worth starting the morning with a glass of water to start the metabolism after sleep. It is also useful to drink some water 20-30 minutes before eating. The thing is that sometimes we confuse thirst with hunger, although in fact we need water. A glass of water before eating can help you not to overeat.
- During physical exertion and in hot weather, you should drink more than usual.
- To maintain optimal water balance, it is important to listen to the body’s signals: pay attention to the frequency of urination, the color of urine, and the condition of the skin.