Learn how hydration affects energy, fitness, recovery and overall health while understanding how much water your body needs daily.
Water supports essential body functions including temperature regulation, digestion, circulation and physical performance.
Proper hydration also helps maintain energy levels, concentration and recovery after exercise.
Water requirements vary based on:
Many people benefit from approximately 2–4 litres of water daily depending on activity levels.
A commonly cited guideline is about 30–35 ml of water per kilogram of body weight per day (roughly 0.5–0.6 oz per lb). For a 70 kg (154 lb) adult, that works out to roughly 2.1–2.5 litres daily, before accounting for exercise, heat, or climate — all of which increase the target.
This per-kg method is a useful starting point because it scales with body size, unlike flat "8 glasses a day" advice, though individual needs still vary with health conditions and activity.
Yes — excessive water intake in a short period can be harmful, so balance matters more than maximizing intake.
Coffee and tea do contribute to daily fluid intake, though plain water is still the best default choice.
Common signs include fatigue, dark urine, headaches, and dry mouth — see the section above for the full list.
Use our free Water Intake Calculator to estimate your recommended daily hydration target.
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