How much water to drink per day

Water makes up 60% of your body weight and is involved in every biological function. Yet most people don't drink enough — and the common recommendation ('2 liters a day') is too simplistic. Your actual need depends on your weight, activity, diet, and environment.

Steps

1

Estimate your baseline need

The simple rule: 30 to 35 ml per kg of body weight. For a 70 kg person, that's 2.1 to 2.45 liters per day, including food. Water in fruits, vegetables, and soups counts — it's not just the water you drink.

2

Add 500 ml per hour of exercise

During exertion, you lose 0.5 to 1.5 liters of sweat per hour depending on intensity and heat. Add at least 500 ml per hour of moderate exercise. For intense workouts or in hot weather, increase this to 750 ml-1 liter.

3

Account for climate and altitude

Heat, dryness, and altitude increase fluid loss. In summer or at high altitudes, increase your intake by 500 ml to 1 liter per day. Air conditioning and heating also dry you out — indoor environments aren't neutral.

4

Track your consumption for a few days

Use a marked bottle or count your glasses for 3-4 days. Most people find they drink 30-50% less than needed. Once you see the numbers, making adjustments becomes concrete and motivating.

5

Listen to your body's signals

The color of your urine is the best indicator: pale yellow = well hydrated, dark yellow = drink more. Thirst appears when you're already 1-2% dehydrated. Don't wait until you're thirsty to drink — build a regular habit.

Why hydration is fundamental

Water transports nutrients, flushes waste, regulates body temperature, lubricates joints, and supports digestion. Dehydration of just 2% decreases physical performance by 10-20% and measurable cognitive performance. Water is also involved in lipolysis (fat burning) — being chronically dehydrated can slow down weight loss.

Factors that change your needs

Your hydration needs vary greatly by season, altitude, diet type (high salt = more water needed), caffeine/alcohol consumption (moderate diuretic effect), and medications. Pregnant or breastfeeding women have increased needs of 300-700 ml/day. Older adults lose their sense of thirst — they should drink 'by habit' rather than waiting for the sensation.

Recognizing dehydration

The first signs are fatigue, headaches, decreased concentration, and dark urine. Moderate dehydration causes cramps, dry skin, and an elevated heart rate. Dizziness, confusion, or not urinating for more than 8 hours is a medical emergency. Most people live in a state of mild chronic dehydration without realizing it.

FoodCraft Tip

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Frequently asked questions

Is '8 glasses a day' true?
It's a rough approximation. 8 glasses of 250 ml = 2 liters, which suits a moderately active 60 kg person. But a 90 kg person or an athlete will need much more. Calculating by kg of body weight is more accurate.
Does coffee dehydrate you?
Not as much as people think. Caffeine has a mild diuretic effect, but the water in the coffee more than compensates for it. Up to 3-4 cups a day, coffee contributes positively to your hydration. Beyond that, the diuretic effect becomes more pronounced.
Can you drink too much water?
Yes, it's called hyponatremia — a dangerous dilution of blood sodium. It's rare and mostly affects marathon runners who drink excessively during exertion. For a healthy adult in daily life, the risk is almost zero below 6-7 liters per day.
Does sparkling water hydrate as well as still water?
Yes, exactly the same. Dissolved CO2 does not affect water absorption. The only difference: sparkling water can cause bloating for some people. In terms of hydration, it's strictly equivalent.

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