This Is How Much Water You Should Drink A Day, According To Experts

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Hydration — or, rather, the lack of it — has been on my mind lately. Recently, I got sick with some sort of virus, and let’s just say, it wasn’t the respiratory kind. I’ll spare you the gory TMI, but after a couple days of losing more fluid than I could replace on my own, I had to go to A&E. “I’m achy, exhausted, weak, and also foggy and weirdly sad,” I told the doctor as she pricked my arm to attach a rehydration IV. “It’s the dehydration,” she nodded. “It literally affects everything. You’ll feel better after this.” One hour and 1,000 ml of rehydration fluid later, she was right — I did feel better. Not good as new, mind you, but definitely no longer as achy, weak, and tired — and, thankfully, also no longer in the depths of emotional despair. It was kind of magical. So much so, that it made me rethink my commitment to staying hydrated every day. Not just for my body, but for my mind and spirit, too.

When it comes to how much water you should drink a day, you’ve probably memorised this go-to hydration rule: Aim for eight 8 glasses daily. It’s one of those ubiquitous health guidelines that’s been etched into our brains since the beginning of time — right up there with getting our 10,000 steps and eight hours of sleep. It’s also, let’s face it, suspiciously specific. After all, everyone’s body is a little different; we’re all different shapes and heights, we all live in different places and participate in different activities. Can there really be a one-size-fits-all standard for our individual hydration needs?

“Dehydration can cause dizziness and headaches, but it may also affect mood, memory, and motor skills,” explains April Panitz, MS, a New York Certified dietitian, registered nutritionist, and the co-founder of Amenta Nutrition. “We need water for all of our cells and systems to function properly. Water is essential for life.”

What are the signs of dehydration?

Of course, you needn’t wait until you require a trip to the ER to know you’re dehydrated — and in fact, please don’t. There are better, less traumatic ways. The easiest: take a peek before you flush. “Pale, clear yellow urine indicates that you are hydrated, while dark yellow or amber may mean that you’re dehydrated,” explains Panitz, though she notes that certain medications, supplements, and foods can affect the colour of your urine. To that end, she recommends also monitoring the frequency of your trips to the bathroom: “You should be going between five to seven times a day,” she says.

It’s also a good idea to monitor other bodily functions as well. “There are several symptoms of inadequate fluid intake, including dry mouth, lips, dry mucous membranes, headache, dry or sunken eyes, and constipation,” explains nutrition scientist and human performance expert Dr. Michael Hartman, PhD.

Experiencing the sensation of thirst is often the very first sign of dehydration. “If you are finding yourself thirsty throughout the day, you should probably be drinking some water,” Panitz says. “Our bodies want to be in a state of homeostasis, so when fluid intake is low, our bodies release antidiuretic hormone which triggers the kidneys to hold onto water and initiates the thirst response.” So, pour yourself a nice tall glass of water or refill your water bottle when you feel thirsty — it’s a clear sign your body needs it.

What are the benefits of drinking water?

Our bodies are about 60 percent water, but we lose water by just living our lives — moving, sweating, going to the bathroom, breathing. That’s why staying properly hydrated really does affect everything — including body temperature, digestion, joint health, and even the plumpness of our skin. “Water helps to maintain blood volume and is the main vehicle for nutrient supplementation and waste removal throughout the body,” Panitz says. “Staying hydrated is also vital for maintaining kidney and metabolic health; having enough urine flow is important to prevent kidney stones and the recurrence of urinary tract infections.” It also ensures our muscles and organs have the fluids and electrolytes they need to function optimally and aids in the breakdown of food to keep our bowels running, ahem, smoothly.

And, as I found out the hard way, staying hydrated also has a major influence on our minds and moods. “Mentally, being hydrated has been shown to enhance concentration, memory, and cognitive function,” says Dr. Hartman. “Emotionally, proper hydration reduces anxiety, depression and other mood disorders.”

If that’s not enough to make you want to drink up, remember this: You can’t survive without water — literally. “You can go a few weeks without food, but without water, you’ll only live a few days,” Panitz says.

How much water do you really need to drink per day?

Just as I suspected, the undying eight rule is fake news. “The ‘eight glasses a day’ rule is not scientifically supported,” Dr. Hartman says. “It’s a quasi-fact.” He says the amount of water you need each day truly does depend on a variety of factors — like your age, body weight, height, and activity level, as well as medical conditions like pregnancy, breastfeeding, and certain kinds of kidney and heart disease. And, the climate and altitude of where you happen to be plays a part, too.

Is water the only way to stay hydrated?

Both Panitz and Dr. Hartman agree that water really is the best for hydration — but it’s certainly not the only method. “All fluids can provide hydration — water, juice, teas, smoothies, soda, soups and sparkling water,” Panitz says. “When we are talking about how much water to drink per day, we are really talking about how much fluid you should have on a daily basis, including the fluid in food.” Dr. Hartman says that cucumbers, romaine lettuce, bell peppers, cauliflower, watermelon and fresh berries are all excellent examples of food with high water contents. “As much as 90 percent of these foods’ total weight can be attributed to water,” he says. “True hydration comes from eating a colourful and vibrant palette.”

And, even foods that you wouldn’t normally think of as hydrating — like bread, chicken and cheese — contain some water that can ultimately contribute to your total fluid intake over the day, as well. “So, next time you’re having that turkey sandwich with lettuce, tomato and pickles at lunchtime, keep in mind that all of the ingredients are contributing to your daily fluid intake,” Panitz says. “Plus, you’re increasing your vitamins, minerals and fibre, too.”

Still, it’s important to remain mindful that not all fluids are created equal. “Soda, juice and sweetened beverages are higher in calories and sugar and should be consumed in moderation,” Pantiz says.

Are caffeinated beverages hydrating?

If you’ve been told that coffee and black tea are dehydrating devils, you’re not alone. “There used to be a belief that caffeinated drinks were dehydrating because they increase the production of urine, but studies have shown that caffeinated beverages actually do contribute to total fluid intake,” Panitz says. Another quasi-fact! So, go ahead and count your morning oat milk latte as part of your required ounces; the amount of liquid in the coffee and milk should cancel out the diuretic effect. Just don’t go crazy — and remember, when it comes to staying hydrated, good old H20 is usually your best bet.

“I recommend getting most of your fluids from water, sparkling water, herbal teas, water flavoured with a splash of juice or a squeeze of citrus, and of course, fruits and vegetables,” Panitz says. “Plain water, along with a diet that includes a variety of fruits and vegetables — which naturally contain electrolytes like sodium, potassium and magnesium — is usually all you need.”

This article was originally published on British Vogue.

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