The body is about 60 percent water, give or take.
We’re constantly losing water from our bodies, primarily via urine and sweat.
There are many different opinions on how much water we should be drinking every day.
Photo credit: Shutterstock
The health authorities commonly recommend eight 8-ounce glasses, which equals about 2 liters, or half a gallon.
This is called the 8×8 rule and is very easy to remember.
However, there are other health gurus who think we’re always on the brink of dehydration and that we need to sip on water constantly throughout the day … even when we’re not thirsty.
As with most things, this depends on the individual and there are many factors (both internal and external) that ultimately affect our need for water.
I’d like to take a look at some of the studies on water intake and how it affects the function of the body and brain, then explain how to easily match water intake to individual needs.
Can More Water Increase Energy Levels and Improve Brain Function?
Many people claim that if we don’t stay hydrated throughout the day, our energy levels and brain function can start to suffer.
There are actually plenty of studies to support this.
In one study in women, a fluid loss of 1.36 percent after exercise did impair both mood and concentration, while increasing the frequency of headaches (1).
However, keep in mind that just 1 percent of body weight is actually a fairly significant amount. This happens primarily when you’re sweating a lot, such as during exercise or high heat.
Bottom Line: Mild dehydration caused by exercise or heat can have negative effects on both physical and mental performance.
Does Drinking a Lot of Water Help You Lose Weight?
There are many claims about water intake having an effect on body weight… that more water can increase metabolism and reduce appetite.
According to two studies, drinking 500 ml (17 ounces) of water can temporarily boost metabolism by 24-30 percent (8).
The top line below shows how 500 ml of water increased metabolism (EE—Energy Expenditure). You can see how the effect diminishes before the 90 minute mark (9):
The researchers estimate that drinking 2 liters (68 ounces) in one day can increase energy expenditure by about 96 calories per day.
It may be best to drink cold water for this purpose, because then the body will need to expend energy (calories) to heat the water to body temperature.
One study showed that dieters who drank 500 ml of water before meals lost 44 percent more weight over a period of 12 weeks, compared to those who didn’t (12).
Overall, it seems that drinking adequate water (especially before meals) may have a significant weight loss benefit, especially when combined with a healthy diet.
Bottom Line: Drinking water can cause mild, temporary increases in metabolism and drinking it about a half hour before meals can make people automatically eat fewer calories.
Does More Water Help Prevent Health Problems?
There are several health problems that may respond well to increased water intake:
- Constipation: Increasing water intake can help with constipation, which is a very common problem (13, 14, 15).
- Cancer: There are some studies showing that those who drink more water have a lower risk of bladder and colorectal cancer, although other studies find no effect (16, 17, 18, 19).
- Kidney stones: Increased water intake appears to decrease the risk of kidney stones (20, 21).
- Acne and skin hydration: There are a lot of anecdotal reports on the internet about water helping to hydrate the skin and reducing acne, but I didn’t find any studies to confirm or refute this.
Bottom Line: Drinking more water may help with several health problems, such as constipation and kidney stones.
Do Other Fluids Count Toward Your Total?
Plain water is not the only thing that contributes to fluid balance, other drinks and foods can also have a significant effect.
However, the studies show that this isn’t true, because the diuretic effect of these beverages is very weak (22).
Most foods are also loaded with water. Meat, fish, eggs and especially water-rich fruits and vegetables all contain significant amounts of water.
If you drink coffee or tea and eat water-rich foods, then chances are that this alone is enough to maintain fluid balance, as long as you don’t sweat much.
Bottom Line: Other beverages that you drink also contribute to fluid balance, including caffeinated drinks like coffee and tea. Most foods also contain water.
Trust Your Thirst … It’s There For a Reason
Maintaining water balance is essential for our survival.
For this reason, evolution has provided us with intricate mechanisms for regulating when and how much we drink.
When our total water content goes below a certain level, thirst kicks in.
This is controlled by mechanisms similar to things like breathing… we don’t need to consciously think about it.
For the majority of people, there probably isn’t any need to worry about water intake at all… the thirst instinct is very reliable and has managed to keep us humans alive for a very long time (23).
There really is no actual science behind the 8×8 rule. It is completely arbitrary (24).
That being said, there are certain circumstances that may call for increased water intake… that is, more than simple thirst commands.
The most important one may be during times of increased sweating. This includes exercise, as well as hot weather (especially in a dry climate).
If you’re sweating a lot, make sure to replenish the lost fluid with water. Athletes doing very long, intense exercises may also need to replenish electrolytes along with water.
Water need is also increased during breastfeeding, as well as several disease states like vomiting and diarrhea.
Older people may need to consciously watch their water intake, because some studies show that the thirst mechanisms can start to malfunction in old age (25).
Bottom Line: Most people don’t need to consciously think about water intake, because the thirst mechanism in the brain is very effective. However, certain circumstances do call for increased intake.
How Much Water is Best?
At the end of the day, no one can tell you exactly how much water you need. As with most things, this depends on the individual.
Do some self experimentation … some people may function better with more water than usual, while for others it only causes the inconvenience of more frequent trips to the bathroom.
That being said, I am not sure if the small benefits of being “optimally” hydrated are even worth having to consciously think about it. Life is complicated enough as it is.
If you want to keep things simple (always a good idea), then these guidelines should apply to 90 percent of people:
- When thirsty, drink.
- When not thirsty anymore, stop.
- During high heat and exercise, drink enough to compensate for the lost fluids.
- That’s it.
YOU MIGHT ALSO LIKE
By Karen L. Smith-Janssen
Colette Pichon Battle gave a December 2019 TEDWomen Talk on the stark realities of climate change displacement, and people took notice. The video racked up a million views in about two weeks. The attorney, founder, and executive director of the Gulf Coast Center for Law & Policy (GCCLP) advocates for climate justice in communities of color. Confronted with evidence showing how her own South Louisiana coastal home of Bayou Liberty will be lost to flooding in coming years, the 2019 Obama Fellow dedicates herself to helping others still reeling from the impacts of Katrina face the heavy toll that climate change has taken—and will take—on their lives and homelands. Her work focuses on strengthening multiracial coalitions, advocating for federal, state, and local disaster mitigation measures, and redirecting resources toward Black communities across the Gulf South.
EcoWatch Daily Newsletter
Between 2000 and 2013, Earth lost an area of undisturbed ecosystems roughly the size of Mexico.
- Planting Projects, Backyard Habitats Can Re-Create Livable Natural ... ›
- Humans Are Destroying Wildlife at an Unprecedented Rate, New ... ›
- UN Biodiversity Chief: Humans Risk Living in an 'Empty World' With ... ›
- Scientists Warn Worse Pandemics Are on the Way if We Don't ... ›
- Coronavirus Pandemic Linked to Destruction of Wildlife and World's ... ›
By Stuart Braun
"These are not just wildfires, they are climate fires," Jay Inslee, Governor of Washington State, said as he stood amid the charred remains of the town of Malden west of Seattle earlier this month. "This is not an act of God," he added. "This has happened because we have changed the climate of the state of Washington in dramatic ways."
'These Aren't Wildfires'<p>Sam Ricketts, who led climate policy and strategy for Governor Jay Inslee's 2020 presidential campaign, tweeted on September 11 that "These aren't wildfires. These are #climatefires, driven by fossil fuel pollution."</p><p>"The rate and the strength and the devastation wrought by these disasters are fueled by climate change," Ricketts told DW of fires that have burnt well over 5 million acres across California, Oregon, Washington State, and into neighboring Idaho. </p><p>In a two-day period in early September, Ricketts notes that more of Washington State burned than in almost any entire fire season until now, apart from 2015. </p><p>California, meanwhile, was a tinderbox after its hottest summer on record, with temperatures in Death Valley reaching nearly 130 degrees Fahrenheit, according to the U.S. National Weather Service. It has been reported as the hottest temperature ever measured on Earth.</p>
<div id="29ad9" class="rm-shortcode" data-rm-shortcode-id="8346fe7350e1371d400097cd48bf45a2"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1306969603180879872" data-partner="rebelmouse"><div style="margin:1em 0">Drought-parched wetlands in South America have been burning for weeks. https://t.co/pjAKdFcKPg #Pantanal https://t.co/ImN2C5vwcp</div> — NASA Earth (@NASA Earth)<a href="https://twitter.com/NASAEarth/statuses/1306969603180879872">1600440810.0</a></blockquote></div><p>As evidenced by Australia's apocalyptic Black Summer of 2019-2020, fires are burning bigger and for longer, with new records set year-on-year. Right now, Brazil's vast and highly biodiverse Pantanal wetlands are suffering from catastrophic fires.</p>
#climatefires Started in Australia<p>Governor Inslee this month invoked the phrase climate fires for arguably the first time in the U.S., according to Ricketts.</p><p>But the term was also used as fires burnt out of control in Australia in late 2019. In the face of a 2000km (more than 1,200 miles) fire front, and government officials and media who <a href="https://www.dw.com/en/trump-climate-change-denial-emissions-environment-germany-fake-heartland-seibt/a-52688933" target="_blank">played down the link to climate change</a>, Greens Party Senator Sarah Hanson-Young and a friend decided that reference to bushfires was inadequate. </p><p>"We both just said, we've got to start calling them climate fires, that's what they are," the Australian Senator told DW.</p><p>Hanson-Young says scientists have been warning for decades that these would be the effects of global heating. "We've been told these kinds of extreme weather events and destruction is what climate change would look like, and it's right here on our doorstep," she said from her home state of South Australia — where by early September fire warnings had already been issued.</p><p>"Calling them climate fires was making it absolutely crystal clear. It is essential that there's no ambiguity," she said </p><p>Having deliberately invoked the term, Hanson-Young soon started to push it on social media via a #climatefires hashtag. </p>
How to Talk About the Urgency of Global Heating<p>The need to use more explicit language when talking about extreme weather events linked to climate change is part of a broader push to express the urgency of global heating. In 2019, activist Greta Thunberg tweeted that the term "climate change" did not reflect the seriousness of the situation. </p><p>"Can we all now please stop saying 'climate change' and instead call it what it is: climate breakdown, climate crisis, climate emergency, ecological breakdown, ecological crisis and ecological emergency?" she wrote. </p><p>"Climate change has for a long time been talked about as something that is a danger in the future," said Hansen-Young. "But the consequences are already here. When people hear the word crisis, they understand that something has to happen, that action has to be taken."</p><p><span></span>Some terms are now used in public policy, with state and national governments, and indeed the EU Parliament, declaring an official climate emergency in the last year. </p>
Words That Reflect the Science<p>But while the West Coast governors all fervently link the fires to an unfolding climate crisis, U.S. President Donald Trump continues to avoid any reference to climate. In a briefing about the fires, he responded to overtures by Wade Crowfoot, California's Natural Resources Secretary, to work with the states on the climate crisis by stating: "It'll start getting cooler. You just watch." Crowfoot replied by saying that scientists disagreed. Trump rejoined with "I don't think science knows, actually." </p><p>It was reminiscent of the anti-science approach to the coronavirus pandemic within the Trump administration, <a href="https://www.dw.com/en/donald-trump-admits-playing-down-coronavirus-risks/a-54874350" target="_blank" rel="noopener noreferrer">at least publicly</a>. Fossil fuel companies are also benefiting from his disavowal of climate science, with the Trump administration having <a href="https://www.dw.com/en/opinion-trumps-paris-climate-accord-exit-isnt-really-a-problem/a-51124958" target="_blank" rel="noopener noreferrer">pulled out of the Paris Agreement</a> and reopened fossil fuel infrastructure like the Keystone XL pipeline. </p><p>But the science community has responded, with Scientific American magazine endorsing Trump's Democratic presidential challenger Joe Biden, the first presidential endorsement in its 175-year history. </p><p>Hanson-Young says the use of explicit language like climate fires has also been important in Australia due to the climate denialism of politicians and the press, especially in publications owned by Rupert Murdoch. As fires burnt out much of Australia's southeast coast, they were commonly blamed on arson — a tactic also recently used in the U.S.</p>
Climate Rhetoric Could Help Decide Election<p>The language of climate has begun to influence the U.S. presidential election campaign, with Democratic nominee Joe Biden labelling President Trump a "climate arsonist."</p><p>Biden is touting a robust climate plan that includes a 2050 zero emissions target and a return to the Paris Agreement. Though lacking the ambition of The New Green Deal, it has been front and center of his policy platform in recent days, at a time when five hurricanes are battering the U.S. Gulf Coast while smoke blanketing the West Coast spreads all the way to the East. </p><p>People are experiencing the climate crisis in a visceral way and almost universally relate to the language of an emergency, says Ricketts. "They know something is wrong."</p>
- The Vicious Climate-Wildfire Cycle - EcoWatch ›
- How Climate Change Ignites Wildfires From California to South Africa ›
- 31 Dead, 250,000 Evacuated in California Fires as Governor ... ›
World's Richest One Percent Are Producing More Than Double the Carbon Emissions as the Bottom 50 Percent
A new report from Oxfam found that the wealthiest one percent of the world produced a carbon footprint that was more than double that of the bottom 50 percent of the world, The Guardian reported. The study examined 25 years of carbon dioxide emissions and wealth inequality from 1990 to 2015.
If you are taking medication for an underactive thyroid, check your prescription.