How much water do we really need to drink? Americans and Europeans take different approaches.

Last month I spent a few weeks on vacation in Europe. I’ve seen the sights. Perhaps the highlight of my trip was a visit to the real Oktoberfest in Munich, where people happily drank many a beer while standing on the picnic benches and singing John Denver’s “Take Me Home, Country Roads.” (The Germans love American singalongs And West Virginia.)

But I maintain that it was good – even necessary – to drink so much beer. How else should I keep myself hydrated?

You see, Europeans don’t share Americans’ love of universally available water. There were hardly any drinking fountains abroad. When eating in a restaurant, water is never served without request. Even commercially available water bottles come in smaller sizes.

This was even the topic of a viral TikTok discussion in July that was summed up with the phrase “Europeans don’t believe in water.” However, Europeans fought back, noting that the typical experience of living on the continent was not the same as that of a tourist. As Bon Appetit noted, “‘Water is basically everything we drink here, but usually carbonated,’ wrote one well-intentioned commenter.”

This whole dichotomy raises significant water questions: Do Americans really drink more water than Europeans? How much water should a person drink? What are the consequences of good or bad hydration? This is actually a really interesting question for Utahns, especially given how many fitness enthusiasts we have. Let’s dive in.

Water consumption data

Unfortunately, hydration isn’t actually a particularly well-researched topic. There is a real shortage of double-blind control group studies with large sample sizes. There are some studies sponsored by beverage companies like Gatorade that don’t scream “biased research.”

There is also a measurement problem. Measuring fluid intake is difficult. It is entirely possible (but annoying) to measure fluid intake and urine output. However, a significant part of the human water cycle is lost in the process: the food we eat provides water, and we sweat a significant amount of it. The color of urine can be an indicator, but may indicate the amount of water a person recently drank rather than their actual hydration status.

Still, we know a little. In particular, we know that there is an absolutely gigantic gap between the actual amount of water that Americans and Europeans drink. A journal article by three leading American nutrition researchers entitled “Water, Hydration and Health” summarized the current state of affairs: “The results of the studies indicate that adults in the United States consume over 2.1 liters of water per day Adults in Europe consume less than 2.1 liters of water.” Half a liter.” Holy crap!

However, to make up the difference, Europeans tend to drink many drinks without water – both alcoholic and non-alcoholic. The numbers vary quite a bit depending on the country: adults in the Czech Republic consume on average about half a liter of alcoholic drink per day and only a tenth of a liter of non-alcoholic drinks, while adults in the Netherlands drink about a quarter of a liter of alcohol, but more than a liter of non-alcoholic drinks.

One study states: “Very low total fluid intake (559 ml) was found in Hungary.” They called their country “Thirsty” for a reason.

Congratulations, you have now read the worst joke ever written.

Even taking into account the European preference for anhydrous drinks that also contain water, Americans are simply significantly more hydrated. For example, the average German would be in the fifth to tenth percentile of Americans in terms of total water intake.

How much water do we need?

So does the average German just live in constant dehydration? Not really. In fact, when 24-hour urine samples from a representative group of over 2,000 Germans were examined over a 24-hour period, only 3% of them were found to be in a state of dehydration. Considering how much more extensive water diets tend to be common in the US, almost everyone is probably in pretty good shape.

But wait, Andy! Even a cursory Google search for “How much water should I drink?” will likely come up with the US National Academies of Sciences, Engineering, and Medicine (NASEM) recommendation. It is The recommendation for adequate water intake is a whopping 15.5 cups (3.7 liters) of liquid per day for men and 11.5 cups (2.7 liters) of liquid per day for women. By these standards, many Americans fall far short of meeting their daily water intake.

So what explains what’s going on? Well, it turns out that NASEM’s estimate isn’t based on much at all. Specifically, almost every American they studied was in a state of good hydration, regardless of whether they were on the high, middle, or low end of water consumption in the study. With this in mind, the agency did something strange by setting the recommended water intake at the average intake of the sample. If anything, the researchers should have learned that lower water intake is also okay.

This is what happens when the available studies on a topic are limited – which was a current theme in these data articles. Whether it’s sunscreen, handwashing, or water consumption, we typically don’t have sufficient data on these very universal topics of improving everyday health.

In the absence of solid data, folklore, myths, and TikTok wisdom abound: people doing water fasts, drinking from giant water bottles during Zoom meetings, and basically guessing the best amount of hydration.

I have to say that I think the German recommendation estimate is a bit more reasonable, around 9 cups of fluid intake per day. At least they were able to find some people who were actually dehydrated in their survey.

The effect of movement

But this failure also reflects a relatively normal level of exertion. Practice can change the game.

In particular, water loss through the skin can vary significantly, ranging from almost negligible to a whopping two liters per hour during high activity and heat. This can actually quickly lead to dehydration and a resulting increase in core body temperature.

Apparently, dehydration leads to reduced performance in these situations – particularly in high-intensity endurance activities such as tennis or long-distance running, with less impact in shorter, energy-intensive activities such as weight lifting. Research also shows that drinking just to quench your thirst does not usually result in rehydration in these situations, meaning mild dehydration can last for hours after physical activity.

There is also some related evidence that dehydration after exercise can lead to short-term psychological effects such as loss of concentration, alertness, and short-term memory loss. However, other studies showed that water deprivation for 24 hours did not result in cognitive decline – in other words, the cognitive declines may be due less to hydration than to other consequences of exercise, such as: B. body temperature.

There are a few other studied effects of hydration to consider: heart, kidney and gastrointestinal function, and headache prevention. On the other hand, there is little evidence that hydration has an impact on skin health.

Overall, however, there isn’t much data to recommend the average American’s preferred approach to water intake compared to the average European. I admit that I skipped my usual water intake when traveling abroad, but I found that after a few weeks I got used to the situation – and didn’t feel any worse. Quenching your thirst is key, as is rehydrating after a workout, but pumping gallons of water into your esophagus probably doesn’t need to be a priority.

Andy Larsen is a data columnist for The Salt Lake Tribune. You can reach him at alarsen@sltrib.com

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