Physical health · a life skill
Deliberate Hydration Planning
one bottle, refilled on a plan
Once you know what your bottle holds, how much you drink is one multiplication: bottles times size. Set the refills for an ordinary day, then decide now what changes on a hot day and an active one, because those are the days you'll be too busy to work it out.
- Moderate
- High impact
- Learn it: 2-4 weeks
- Fifteen minutes to set up, a glance a week
Sam's numbers are an example, not a target. An ordinary day is 3 bottles, 2.25 litres of drinks; a hot day or an active one is 4, 3 litres. The water in food comes on top.
The method
Measure once, plan three days.
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Know what your bottle holds
Read the label or fill it once from a measuring jug. After that, every refill is a known amount.
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Set refills for an ordinary day
Three or four, each tied to a time or an event: arriving at work, lunch, the school run. Each bottle is gone by the next refill.
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Plan the hot day and the active day now
You need more in hot weather and when you're active for a long time. Decide where the extra refills go before the day arrives.
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Check the colour, adjust each week
Pale pee through the day means the plan works. Dark yellow means add a refill. Up at night to pee means move the last one earlier.
One measured bottle, refills at set times, a plan ready for heat and effort, adjusted by colour.
Example: Sam's bottle holds 750 ml. On an ordinary day Sam fills it at 8, 12 and 16: 3 bottles, 2.25 litres. When the forecast says hot, the refills go every three hours from 8, which makes 4. On a five-a-side evening the last refill moves to 19:00, after the game. Sam checks the colour on Sundays and moves a refill if it's been dark.
If a doctor, nurse or dietitian has given you a fluid limit, which can happen with kidney or heart conditions, follow it, not this page. Don't drink a big bottle in one go: EFSA notes adult kidneys can clear at most about a litre an hour. Ask for an urgent GP appointment or call NHS 111 if you feel unusually tired, feel dizzy when you stand up and it does not go away, or have dark yellow pee or are peeing less than normal (NHS).
The refill planner
Set the refills for each kind of day.
1 · Your bottle
2 · Refill times
On hot or long active days, the NHS says you need more. Tea and coffee count too; if you're also timing your caffeine, plan the afternoon refills as water.
3 · Your three days
Tap a refill hour to start
Your plan is kept only in this browser. Nothing is sent anywhere. The totals count drinks only; food adds more on top, about a fifth of total water in the US panel's figures. The drawing assumes the last bottle is finished by 22:00.
What the guidance says
Two panels, two numbers, one condition.
In 2010 the European Food Safety Authority set adequate intakes of total water, drinks and food together: “For water a daily intake of 2.0 litres is considered adequate for women and 2.5 litres for men” (EFSA). The US National Academies, in 2004, put the same kind of figure at about 2.7 litres for women and 3.7 for men, and found that about 80 percent of it comes from drinks (National Academies).
The condition matters more than the gap between them. EFSA's figures “apply only to conditions of moderate environmental temperature and moderate physical activity levels”, and it notes losses in extreme heat and exercise “can be up to about 8,000 mL/day”. The US panel wrote that “Very active individuals who are continually exposed to hot weather often have daily total water needs of six liters or more.”
So one plan for every day is the wrong shape. An ordinary day, a hot day and an active day each get their own refills, and the colour check tells you which one you're short on.
The idea
Why it works.
A known bottle turns “am I drinking enough?” into a count you can do at a glance: three empties by dinner, or two. Refill times tied to events make the count happen without a reminder, the way the simple version hangs a glass on moments you already have.
The days that need more are the ones that leave least room to think: the heatwave commute, the long hike, the match. Deciding the extra refills on a calm evening means the plan is already there when the day isn't.
When it goes wrong
Habits that help.
- The refill time slips. Tie it to an event, not a clock: arriving, lunch, getting home. Events move with your day; 15:00 doesn't.
- The bottle rides home full. Check it at each refill. If it's still half full, the gap is too short or the bottle too big: drop a refill.
- The hot day catches you out. Look at the forecast the night before and switch to the hot-day plan before you leave.
- Drinking it all at once. A bottle that's still full at the next refill isn't a target to catch up on. Sip through the gap; EFSA's kidney limit is about a litre an hour.
Go deeper
Keep going.
- Simple Hydration Planning
- Deliberate Hydration Planning
- Advanced Hydration Planning
Books
Practise this in HourLife.
In Intake: Reminders per item. A one-tap log of what you had today: drinks, food, supplements, and anything else, with daily totals, reminders, and insights.
