How much water do you really need?
Forget the eight glasses rule. Your needs depend on your size, the weather and how much you sweat. Here's a practical way to get it right, including on the Australian summer days that matter most.
Water is the easiest habit in fitness and still one of the most ignored. Being even mildly dehydrated can make training feel harder and make hunger harder to read.
The baseline
Australia’s Nutrient Reference Values set an adequate intake of total water, from food and drinks combined, of about 3.4 litres a day for men and 2.8 litres for women. Of that, roughly 2.6 litres for men and 2.1 litres for women typically comes from drinks. The rest comes from food, especially fruit, vegetables, soups and yoghurt.
A simple personal rule is around 35 ml per kg of body weight from drinks on a normal day. That’s what Logpulse uses for your daily water target. For an 80 kg person it’s 2.8 litres.
Everything counts: water, milk, tea and coffee included. Caffeinated drinks have a mild effect on urine output, but in normal amounts they still add to your total.
When you need more
- Training. Especially long or hot sessions.
- Hot weather. A Queensland summer can easily double your sweat losses.
- Physical work. Tradies outdoors can lose well over a litre an hour.
- Higher protein or fibre diets. Both work better with plenty of fluid.
A simple check
Look at your urine. Pale straw is good. Dark yellow means drink more. Completely clear all day can mean you’re overdoing it.
Rehydrating after sweaty training
Sports nutrition guidance suggests weighing yourself before and after a long or hot session. For every kilogram you lose, drink about 1.25 to 1.5 litres over the next few hours. You drink more than you lost because you keep losing some as urine. If you’ve sweated heavily for hours, a drink or meal with some salt helps you hold on to the fluid.
Can you drink too much?
Yes. Drinking very large amounts quickly, without replacing salt, can dilute the sodium in your blood. This is rare, and mostly a risk in long endurance events. Sip steadily through the day instead of forcing litres down at once.
Make it easy
- Keep a bottle where you can see it
- Drink a glass with every meal
- Have one before and after training
- Log it: “drank 750ml water” is a two second voice log in Logpulse, and you’ll see your daily target fill up
This is general information drawn from published research, not personal medical or dietary advice. If you have a health condition, are pregnant, or have a history of disordered eating, speak to your GP or an Accredited Practising Dietitian first. For support with eating concerns, the Butterfly Foundation helpline is 1800 33 4673.
Sources
- National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand: Water. Updated 2017.
- Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand: exercise and fluid replacement. Medicine and Science in Sports and Exercise. 2007;39(2):377 to 390.