Some people recommend drinking 8 glasses of water per day. Others say that is rubbish and recommend 2 litres ( 4.2 pints ) per day. I measured the water in a common glass size. 0.24 litres. 8 glasses would be 2 litres.
Most of what you read in the media is rubbish because it is over simplified, it does not apply to you. Your water consumption can vary from less than 2 litres up to 4 or more when working hard.
Most of the articles mentioning miracle benefits from drinking more water are hiding the truth. They do not just add water, they replace something harmful like sugar, alcohol, or caffeine. They rarely mention adding more water when you work hard or eat difficult food. Bad advice. Without the full details, you could damage your health by drinking too much water.
You need more water when you consume sugary drinks or alcohol or caffeine because they make your body dump water. A good idea is to drink a glass of water with every coffee or alcoholic drink, adding the water the coffee and ethanol pump out.
You do not add water to refill after drinking sugary drinks as that is just too much water. Instead you replace sugary drinks with pure water.
Eat anything fatty as an energy source? when your body processes fate, there are horrible waste products to be pumped out, taking water with it. You need extra water with fat.
Hot weather? you need extra water to replace the extra sweat. The same when you work hard, your body produces heat which means more sweat and the need for more water.
Bush walking in the warm Australian weather requires a litre per 10 kilometres of walking, assuming you have a full load of water in your body before starting the walk. Hot summers can drain a litre of sweat in just 5 klm. Carrying a full backpack has the same effect.
Working on something in the shade might require a glass of water after two hours while the same work in full sun might require a glass every hour.
Weight loss requires burning more fat than usual which requires more water to flush out the waste chemicals.
Water is water only when it is pure water or consumed as whole food like lettuce leaves or a plum. Water is not useful when anything is added or it is in "juice".
Look at Gatorade. It is supposed to replace lost minerals but it is just a sugary drink doing damage. When I was running marathons, several top athletes paid to promote Gatorade all said the same thing, they actually drink water. If they use Gatorade, they mix one part Gatorade with 3 or 4 or 5 parts water to dilute out the sugar. They would grab their special Gatorade bottle from a separate stand. Their coach would pour out most of the Gatorade and replace it with water.
Juice drinks are just sugar. The sugar in an apple can supply sugar as energy slowly over 30 minutes while your body digests the fruit. The same amount as juice will hit your body hard for 5 minutes, slowing you down to process the sugar, then your body slows down further because your body glucose level bottoms out after the big hit of refined sugar. Never drink fruit. Eat fruit or drink water.
You can drink more when you feel hot. Look at your sweat. That is water going out all over your body. Drink water to replace it. Pour water over yourself to cool down. When running marathons, I used to grab two glasses of water at each stand, drink one, and pour the other on my head.
You can check the colour of your urine. It should be a light colour. Anything darker means your body does not have enough water to flush out waste. It means you should have drunk more water an hour earlier. Drink extra water immediately and think about what you did over the previous hour so you can remember to drink more water the next time you perform the same activity.
Drink a cup of coffee then notice you run to the toilet. You need to add as much water as the caffeine made you pump out.
Hangover? The two main causes are horrible chemicals in cheap drinks and the alcohol dehydrating your brain. Drink water when drinking alcohol. Use less alcohol in mixed drinks. Beer drinkers can switch to very low alcohol versions of some popular beers.
Hot dry climates make your sweat more efficient but they dry out your lungs. Hot humid climates keep your lungs moist but make your sweat less effective, leading to much more sweat. Both need more water.
Dry air conditioning dries out your lungs. Drink more water or flood the air conditioned room with fresh green plants to add moisture back to the air.
Working in a refrigerated storage area? The refrigeration is the same as air conditioning, all the water is removed from the air. Drink more water.
The sun can dry you out fast. The same happens when working near hot machinery or in a vehicle. Pack lots of water for work and travel.
"Replenishment" drinks and "performance" drinks are rarely either. They might have useful amounts of water and minerals but then they add salt and sugar. Anything from America has too much salt and sugar. Pure water is better.
American research from last century showed people losing salt in their sweat. Performance drinks try to replace the lost salt with sodium chloride because it is cheap and it makes you thirst for more, perhaps another bottle. Your body is looking for the potassium it normally receives from vegetables. We eat vegetables and everything else loaded with sodium. Our bodies dump the excess sodium with our sweat. The performance drinks mostly replace the sodium instead of balancing the sodium with potassium.
Vegetable juice is way better than most performance drinks. A small amount of vegetable juice with a lot of water will replace the last water plus help balance the potassium and sodium mix in your metabolism. You need vegetable juice made from fresh vegetables, not faked from concentrates or powders or anything else. You need juice with no added salt because that would destroy the potassium balance. No preservatives because they have weird effects and are often high in sodium.
Carrot juice is a good source of potassium. In a marathon with the opportunity to have custom drinks handed to you, have 300ml of water mixed with 20ml of fresh carrot juice at each drink station. Also grab pure water to pour over your head.
I usually sip water every ten minutes to stop my throat drying out. On a long walk, you can have a big bag of water in your backpack and sip it through a tube but the water in the tube will be warm. Yuck!
You can get insulating covers for the water tube. Some backpacks have foam dividers for insulation. You fill the backpack water bag with a mix of chilled water and ice. You then have cool water to sip for several hours. Camelback is a popular brand of water bag.
I tend to use several regular bottles in the insulated part of my backpack. The bottles contain half ice and half water. I use one at a time outside of the insulated pack. I find it more refreshing to drink from a bottle. I may also mix the bottles with some containing something like oatmilk. Bottles are also easier to fill up if there are drink stations on the walk, something you find at beaches on our most popular coastal walks.
in a cold climate, you might replace cool water with warm water and add a touch of caffeine free herbal tea.
How much is water worth?
Replacing sugary drinks with water saves you dollars each day plus it avoids tends of thousands of dollars for diabetes treatment in later life.
Replacing alcohol has a similar cost benefit. You save on costs and you get huge health benefits.
I like coffee and tend to add a glass of water with each coffee instead of replacing the coffee with water. I also alternate decaf with regular. A promising future development is the coffee bean with no caffeine. The caffeine free plants exist and are now spreading to mainstream production. Coffee is up to 8% caffeine. Good decaf is 1% caffeine. The future bean is 0% caffeine, the perfect choice for any cup after lunch time.
Black and green tea are 4% caffeine. Herbal tea is 0% although major brands are now owned by cheat companies that sneak regular tea into the herb mix in the hope of addicting customers.
The health benefits of replacing bad drinks with water is enormous. The health benefits of adding water when you need it are just as important. You feel better. You sleep better. You can maintain the effects for life, a longer life or a life where your are healthy and active for longer.
Read about the benefits in the one page junk media articles but research them. They should have references you can follow. Read several investigations from independent sources and different countries. Drop anything that is sponsored, which includes almost all American medical research. Focus on research in your climate, research using people of your age doing the activities you do.
Raise a class of clean pure water. Toast to a longer happier active life!