How Much Water Is Plenty to Drink? It Depends
The not so humble water bottle. Look around and it’s easy to see that this is an indispensable accessory for signaling an active, healthy lifestyle. CDC makes it clear. Drink plenty of water and you can protect yourself from all kinds of health problems: dehydration, fuzzy thinking, mood changes, overheating, constipation, and kidney stones. It will lubricate and cushion your joints, protect your spinal cord, and wash away all kinds of wastes from your body in urine, perspiration, and bowel movements.
You can even find some pretty impressive claims about how much weight people can lose by drinking more water. But with a closer look, you’ll see that these claims come from observations of an association between water consumption and changes in weight. Or from short-term replacement of caloric beverages with plain water.
Eight Glasses per Day?
The ubiquitous advice has long been to drink eight glasses of water per day. That prescription dates back to 1945. But new research in Science seems to be putting the old one-size-fits-all advice firmly into the category of a myth.
Yosuke Yamada and a whole host of collaborators conducted the new study. They did a very precise estimation of water requirements for large sample (5,604) of people. Their subjects came from all over the world and the ages ranged from 8 days to 96 years. The authors tell us:
“The current study clearly indicates that one size does not fit all for drinking water guidelines, and the common suggestion that we should drink eight 8-ounce glasses of water per day (~2 liters) is not backed up by objective evidence.”
So no. Everyone doesn’t need eight glasses of water daily. How much should we drink? As much as it takes to quench our thirst. How hard is that?
Click here for the study, here and here for further perspective.
Water Bottle, photograph by DoctorButtsMD, licensed under CC BY-SA 2.0
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December 8, 2022
December 08, 2022 at 6:40 am, Christine Rosenbloom said:
I always find these “how much water do I need” conversations challenging with family and friends. No matter how many times I say “it depends” on many factors, they still want a number, a very specific number, like 8 glasses a day!
December 08, 2022 at 8:49 am, Anne Fletcher said:
I believe that that the older one gets, the less reliable thirst is as an indicator of water needs. In other words, thirst is not a good indicator of liquid needs in the elderly. Also, water is not the only way to get water. Plenty of other liquids can meet our fluid needs.
December 08, 2022 at 9:30 am, John DiTraglia said:
yeah that article was as clear as mud. they actually found that we drink more than 8 glasses a day on average. the one factor that was not considered was how much did those free range people drink and why. lots of people think they should drink a lot.
but the biology of thirst might be an interesting and instructive analog of hunger that is not yet quite as fraught.