Water is the basic “cooling system” and transport for the entire body: it helps with digestion, thermoregulation, heart and brain function, and the elimination of metabolic waste products. The myth of “eight glasses” is convenient, but too crude. The real need depends on body weight, activity, climate, and health. For most adults, a comfortable range is about 2–2.5 liters per day, but it’s more accurate to aim for 30–40 ml per kilogram of weight: a 70 kg person usually needs about 2.1–2.8 liters of fluid per day, including drinks and water from food. If you’re exercising or working in the heat, add another half liter to a liter and do it evenly throughout the day, in small portions.
The simplest “litmus” is the color of your urine: a light, almost transparent shade usually means that everything is fine. When you don’t have enough water, headaches and lethargy become more frequent, your skin loses its elasticity, and digestion “slows down.” To prevent this from happening, keep a bottle at hand, take a few sips during meals — this doesn’t hinder digestion, but on the contrary helps — and choose “watery” foods like cucumbers, watermelon, apples, and leafy salads more often. Sugary drinks and alcohol don’t replace water and can worsen dehydration, so it’s best to limit them.
There are exceptions. During pregnancy and breastfeeding, with kidney or heart disease, and when taking diuretics, the amount of drinking should be agreed with your doctor. In other cases, simple logic works: drink regularly, adjust the amount to the weather and load, and look at the body's signals. This way it's easier to keep your energy, clear head, and skin in good shape without unnecessary mathematics.
