# How much water should you drink a day? Daily water intake for people who train > Daily water intake for adults: about 2.7 to 3.7 litres total from food and drink, with thirst and pale-yellow urine as guides, plus extra for sweaty training and heat. Published 2026-11-13 · Updated 2026-11-13 · revns editorial **Daily water intake** for healthy adults is about **2.7 litres per day for women** and **3.7 litres per day for men** from **all sources**—drinks **and** water in food—not a single number on a bottle. The U.S. National Academies published those **adequate intake** figures from national survey data; they are planning values, not a test you pass at 6 p.m. For people who train, the useful habit is **drink to thirst most days**, keep urine **pale yellow**, and **add fluid around sweaty sessions** in heat. Use the [water intake calculator](/tools/water-intake-calculator) as a starting point, then adjust from your sweat rate and how you feel. **TL;DR** | Who / when | Practical target | | --- | --- | | **Women, average day** | ~**2.7 L total water**; roughly **2.0–2.2 L from drinks** if food supplies the rest | | **Men, average day** | ~**3.7 L total water**; roughly **2.5–3.0 L from drinks** | | **Quick body-weight rule** | **30–35 ml per kg** body weight as **drinks** on a normal day (calculator default) | | **Training** | **+~0.5 L per 30 min** of sweaty work; more in heat | | **Check yourself** | **Thirst** + **pale-yellow urine**; dark urine for a full day means drink more | | **Avoid** | Chugging litres per hour in races; **hyponatremia** is rare but serious | ## How much water should I drink a day? Guidelines talk about **total water**: everything that reaches your blood, from plain water, milk, tea, coffee, juice and the water inside fruits, vegetables, dal, rice and yoghurt. The **Dietary Reference Intakes** report from the U.S. National Academies (2005) set **Adequate Intake** for total water at: - **~2.7 litres/day** for women aged 19–70+ - **~3.7 litres/day** for men aged 19–70+ Those numbers came from **median intakes** in U.S. survey data in people who appeared hydrated, not from a controlled trial that proved exact millilitres. The report noted that **roughly 80% of total water often comes from beverages** and **about 20% from food**, though food share rises with a high-fruit and vegetable diet. The **NHS** uses simpler language: aim for **6 to 8 cups or glasses of fluid a day**, and **drink more** if you are **pregnant or breastfeeding**, in **heat**, **physically active for long periods**, or **ill**. It also says to use **pee colour**: **clear pale yellow** is the everyday goal. None of these replace individual medical advice. People with **kidney disease**, **heart failure** on fluid restrictions, or **diabetes** with specific plans should follow their clinician, not a blog. ## What counts as water intake? Almost everything liquid counts toward fluid. So do high-water foods. **Drinks that count** - Plain **water** (still or sparkling) - **Milk** and unsweetened **plant milks** - **Tea** and **coffee** in moderate amounts - **Soup** and broth - **Dal**, smoothie and juice (watch sugar if that matters for your goals) **Food that adds meaningful water** - Cucumber, melon, berries, oranges, grapes - Lettuce, tomato, courgette - Cooked dal, rice and pasta (they hold cooking water) - Curd and yoghurt **Alcohol** is a diuretic at higher doses and hurts sleep and recovery; it is not a hydration strategy. See how alcohol affects sleep in the [sleep guide](/blog/how-much-sleep-do-you-need) if you log evenings out next to training. [Meal tracking](/features/meal-tracking) without obsessive calorie counting can still note **a glass of water with meals** and **fluid around sessions**, which matters more than hitting a mythical eight glasses by noon. ## What is the 30–35 ml per kg rule? Sports nutrition coaches often estimate **beverage** needs as: **Body weight (kg) × 30 to 35 ml = daily drink range** Example: a **70 kg** person → **2.1 to 2.45 litres** from drinks before training extras. That lines up loosely with National Academies figures when food adds another **0.5–1.0 litre**. The [water intake calculator](/tools/water-intake-calculator) uses this band plus training minutes. It is a **starting estimate**, not a prescription. A **55 kg** cyclist in winter may drink less than a **90 kg** lifter in the same office. **Menopause**, **high altitude**, **air travel** and **high-fibre vegetarian meals** (more water in stool) all shift needs without changing the equation. ## How much extra water do you need for exercise? Sweat rate beats any table. Two people at the same pace in the same heat can lose **0.5 litre/hour** or **1.5 litre/hour**. ### Before training If you are not thirsty, **200–500 ml** in the **2–4 hours** before a hard session is a common sports-medicine suggestion. Right before start, **small sips** are enough unless you arrive very thirsty. ### During training For **sessions under about an hour** in mild weather, **water at thirst** is fine for most healthy adults. For **longer** or **hot** efforts: - Aim to **replace most sweat losses** so body weight does not drop more than about **2%** from start to finish (a common benchmark in ACSM and athletic guidance). - **Weigh nude or in dry clothes** before and after a one-hour run or ride; each **1 kg lost** is roughly **1 litre** of fluid to replace, plus a little extra if you will keep sweating. The [heat and carbohydrate study guide](/blog/heat-exercise-carbohydrate-oxidation-study-2026) explains why **fluid and sodium** matter when core temperature rises; dehydration there made fuel use harder even when drinks were planned in the lab. ### After training Drink until **thirst eases** and urine lightens. With **heavy sweat**, pair water with **sodium** (food or sports drink) on efforts **longer than about 90 minutes**; see [electrolytes](/dictionary/electrolytes). ## Does training type change hydration? **Strength training:** Many people sip between sets; total sweat is often **modest** unless the gym is hot. **Creatine** pulls a little water into muscle; the [creatine guide](/blog/creatine-evidence-dose-and-myths) notes that **normal drinking** covers it—no forced over-hydration. **Running and field sports:** Higher sweat rates; **carrying a bottle** or planning loops past a tap helps. **Cycling:** Long duration makes **planned drinking** essential; use bottle cages and set a **timer every 15–20 minutes** in heat. **Swimming:** Sweat still happens; **dry mouth** after pool sessions is a cue. **Yoga and walking:** Usually **thirst alone** is enough unless heat is extreme. Match hydration to **[TDEE](/blog/tdee-and-maintenance-calories-explained)** indirectly: bigger people and longer sessions burn more and often sweat more, so the calculator’s weight and time inputs track real life better than a single “2 litres for everyone” sticker. ## How do you know if you are drinking enough? Use **three low-tech signals**: 1. **Thirst** — reliable for most healthy adults during everyday life and moderate exercise. 2. **Urine colour** — **pale yellow** like lemonade; **apple-juice dark** for a full day suggests more fluid. 3. **Weight trend** — **sudden scale drop** after a long hot workout is mostly water; **rehydrate before** the next hard day. **Morning urine** is naturally darker; judge the **daytime** pattern. Signs you may need **more** fluid: - Headache with heat and little urine - Dizziness standing up after sweaty work - **Hard stools** (types 1–2 on the Bristol scale); fluid works with fibre—see the [Bristol stool guide](/blog/healthy-poop-bristol-stool-scale-guide) Signs you may be **overdoing plain water** (especially in long races): - **Swelling** without injury, **nausea**, **confusion**, **severe headache** during or after hours of slow running while drinking every station—think **hyponatremia** and get emergency care. ## Do women and men need different amounts? Yes on average, because **body size** and **composition** differ. The National Academies **2.7 vs 3.7 litre** split reflects surveyed medians, not a moral rule. **Menstrual cycle:** Some people drink more in the **luteal phase** or feel **bloat**; thirst and weight, not a fixed chart, should drive changes. **Pregnancy and breastfeeding:** NHS and many national bodies recommend **extra fluid**; follow **antenatal** advice. **Do not** restrict water because of scale weight without a clinician. **Older adults:** Thirst can blunt with age; **scheduled drinks with meals** and **checking urine** help if you train in your 60s and 70s. Anyone on **gender-affirming hormones** should use **body weight and activity**, not a stereotype, and discuss **blood pressure** or **kidney** meds with their doctor. ## What about protein, fibre and caffeine? **Higher protein** (common in lifting) still fits within the same **fluid habits** as everyone else when you follow the [protein guide](/blog/how-much-protein-per-day); extra litres are not required for healthy kidneys. **High fibre** (vegetarian and vegan athletes) needs **more water** to keep stool soft—pair with the [gut health tracker](/features/gut-health-tracker) if you log Bristol types. **Caffeine** in **moderate** coffee or tea **counts toward fluid** for healthy people. If **sleep** drops below **seven hours**, fix timing before blaming dehydration. Log sleep in [sleep tracking](/features/sleep-tracking) next to training. ## What should you do this week? 1. **Run the calculator** with your weight and typical **weekly training minutes**. Write the **base** and **training** numbers in your phone notes. 2. **Pick one habit:** a **500 ml bottle** on your desk and **refill once**, or **one full glass** with each meal. 3. **Do one sweat test:** weigh before and after a **60-minute** session; replace **~1 litre per kg lost**. 4. **Log for seven days** in revns or a notebook: **wake urine colour (1–3)**, **training fluid**, **headache y/n**. Patterns beat one perfect day. 5. **Heat week:** pre-cool, carry fluid, and read the heat article linked above before a long outdoor effort. **Diet-inclusive hydration ideas** - **Vegetarian / vegan:** coconut water in small amounts on long rides (watch sugar), lime water with pinch of salt, cucumber raita, watermelon after sessions. - **Eggetarian:** buttermilk (chaas) with lunch, boiled egg meals with soup. - **Non-vegetarian:** bone broth or rasam with rice after evening training in humid weather. ## When to see a professional Talk to a **GP, nephrologist, cardiologist or obstetric team** if you: - Were told to **limit fluids** for heart or kidney disease. - Have **diabetes insipidus**, **kidney stones** with a prescribed plan, or **recurrent urinary infections**—follow their targets, not this article. - Are **pregnant** with **persistent headache**, **swelling** or **very little urine**. - Notice **always** needing more than **4–5 litres** daily without heavy sweat, or **never** feeling thirsty while urine stays dark. **Get urgent care** for **fainting**, **seizure**, **chest pain**, **blood in urine**, **no urine for 12+ hours** with illness, or **confusion** after extreme heat or over-drinking. This is general training guidance, not medical advice. ## Related - [Water intake calculator](/tools/water-intake-calculator) - [TDEE and maintenance calories explained](/blog/tdee-and-maintenance-calories-explained) - [Heat and exercise: carbohydrate use in extreme heat (2026 study)](/blog/heat-exercise-carbohydrate-oxidation-study-2026) - [Healthy poop and the Bristol stool scale](/blog/healthy-poop-bristol-stool-scale-guide) - [How much protein do you need a day?](/blog/how-much-protein-per-day) - [Gut health tracker](/features/gut-health-tracker) ## Sources - [National Academies of Sciences. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate (2005)](https://nap.nationalacademies.org/catalog/10925) - [NHS. Water, drinks and hydration](https://www.nhs.uk/live-well/eat-well/food-guidelines-and-food-labels/water-drinks-nutrition/) - [Sawka MN et al. American College of Sports Medicine position stand: Exercise and fluid replacement. Med Sci Sports Exerc 2007](https://pubmed.ncbi.nlm.nih.gov/17277604/) - [Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement: Nutrition and Athletic Performance. Med Sci Sports Exerc 2016](https://pubmed.ncbi.nlm.nih.gov/26891166/) ## Questions ### How much water should an adult drink per day? The U.S. National Academies set adequate total water intake at about 2.7 litres per day for women and 3.7 litres for men, including water from food and all drinks. That is not a glass-by-glass rule; most healthy adults meet needs by drinking when thirsty and adding fluid around training. ### Does the eight-glasses rule still apply? Not as a law. Eight eight-ounce glasses (about 1.9 litres) is below the adequate intake figures for many adults and ignores water in food. The NHS suggests six to eight cups or glasses of fluid a day as a rough guide, but says you may need more when you are active or in heat. ### How much extra water do you need when exercising? A practical starting point is about 0.5 litre per 30 minutes of sweaty training, on top of your usual day. Weighing yourself before and after a session shows your own sweat rate. In heat, replace most of what you lose and include sodium on long efforts. ### Do coffee and tea count toward water intake? Yes for everyday amounts. Moderate coffee and tea contribute to fluid intake and do not dehydrate healthy adults in studies cited by major dietary reviews. Very high caffeine can disturb sleep, which matters more for recovery than a small diuretic effect. ### Can you drink too much water? Yes. Drinking large volumes of plain water in a short time, especially during long endurance events, can dilute blood sodium (hyponatremia). Drink to thirst in most training, use paced drinking in races, and get urgent care for confusion, seizure or severe headache during or after heavy sweating. ### When should you talk to a doctor about hydration? See a clinician if you are always thirsty despite drinking plenty, urine stays dark for days, you have heart failure or kidney disease and were told to limit fluid, you are pregnant with swelling or headache, or you had dizziness, fainting or very little urine during heat or illness. --- Canonical: https://revns.com/blog/how-much-water-should-you-drink-daily Index of everything: https://revns.com/llms.txt revns gives training guidance, not medical advice.