Between the record-breaking temperatures that took over Europe and the on-going scorchers happening across the United States this summer, it feels a little like the planet is about to combust. The fact is, heat waves have increased in frequency, magnitude and duration across the globe, according to the World Health Organization.
And with these rising temperatures comes an increased need to make sure you're properly hydrated. That said, hotter days aren’t the only reason you need to down more H2O — there’s a slew of health functions that require you to sip a lot.
So, how much water should you drink per day, exactly? And why? Keep reading to find out those answers — plus how to stay properly hydrated, according to health pros.
Why Do We Need Water?
Our bodies — which are made up of about 60 percent water — rely on H2O to survive.
“Water plays an important role in most, if not all, bodily functions,” says Amanda Carney, Director of Health Coaching for THE WELL New York. “It makes up part of our blood, supports detoxification pathways and hydrates us down to the cellular level — yes, even our teeny tiny cells can get dehydrated!” In other words, water carries nutrients to your cells and waste materials to your kidneys (and, ultimately, out of the body).
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It also helps break down food, keep your digestive system running smoothly (think: prevents constipation) and promotes the “bioavailability” of key vitamins, minerals and nutrients, says Alice Figueroa, MPH, RD, a nutritionist in New York City. What’s more, H2O lubricates muscles and joints, cushioning your bones and reducing friction when you move, and keeps your skin, lips and eyes hydrated. And on top of all that, the underrated liquid regulates body temperature and helps reduce the risk of certain conditions, such as urinary tract infections (UTIs), per research.
But sipping on just one or two glasses of water every day doesn’t cut it. “Our body needs water to replace fluids that we lose through sweating, elimination of waste and metabolic activity (production of energy),” says Figueroa. That’s why it’s important to hydrate throughout the day — not just after exercising or when it’s hot outside.
How Much Water Should You Drink Per Day?
In general, women should aim to drink at least 11.5 cups of water per day while men should shoot for 15.5 cups each day, according to the Academy of Nutrition and Dietetics.
However, “each person has unique water needs,” says Figueroa. Meaning, hydration is not one-size-fits-all.
“Our water needs increase as weight increases,” says Anna Brown, RD, a New York City-based integrative nutritionist. “So a good rule of thumb is to divide your weight in pounds by two to determine how many ounces of water you need per day at minimum."
But there are other factors to take into account when deciphering how much water to drink per day, including (but not limited to)...
Activity level: The more you move around, the more H2O you’re going to need to stay hydrated. That’s because exercising increases “breathing and sweating, both of which cause our body to lose fluids and electrolytes,” says Brown. (Quick refresher: Electrolytes are minerals found in your blood that help regulate and control the balance of fluids, e.g. water, in the body, according to the Cleveland Clinic.)
Location: Hanging out in hot and humid weather can increase the amount you sweat and, thus, the amount of water you need to drink. And the same is true if you’re at a higher altitude (such as while skiing or hiking), per the Mayo Clinic.
Health status: Fighting off a fever? Dealing with diarrhea? Vomiting? Make sure to sip on even more water, as these symptoms can cause your body to lose fluids. Other conditions, such as bladder infections, also require increased water intake, according to the Mayo Clinic.
Pregnancy and breastfeeding: Your body works overtime in both of these scenarios, thereby requiring more H2O to stay hydrated. But that’s not all: Drinking more water is key to keep the baby growing steadily and then produce enough milk to nurse, according to the Academy of Nutrition and Dietetics.
“Divide your weight in pounds by two and that’s how many ounces of water you need per day at minimum.”
Oftentimes, the key to staying hydrated is to drink when you notice any “thirst cues," such as dry skin, eyes and mouth, being sluggish, feeling thirsty, says Figueroa. But during a heat wave? You should drink plenty of water "regularly and often" — i.e. “even if you don’t feel thirsty,” according to the American Red Cross. That’s because your body needs water to keep cool and in turn, help you stave off heavy sweating — a key culprit of dehydration, among other heat-induced conditions.
How to Get Plenty of Water Per Day
From the minute you pop out of bed in the am, a myriad of things start fighting for your attention, pulling it away from drinking ample H2O. Because of this, Brown suggests hydrating first thing in the morning.
“We wake up dehydrated after breathing all night, so it helps rehydrate us before we have coffee or tea, which are diuretics,” she explains.
Plus, “when you drink water for at least an hour before your caffeine, you’re supporting your circadian rhythm by allowing cortisol levels to peak naturally,” says Brown. “We want this increase in cortisol in the morning to wake us up fully versus being dependent on caffeine first thing.”
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In addition to kicking off your day with a glass of water, here are ways to reach and/or increase your daily recommended fluid needs:
Add a flavor enhancer: If you get tired of plain water, spice it up by infusing the liquid with fresh citrus, berries or herbs (e.g. mint, rosemary, cilantro, basil or dill).
Eat the right foods: While drinking water is key to staying hydrated, it’s not the be-all and end-all of hydration. Chowing down on certain foods — leafy greens, cucumbers, cantaloupe, apples, tomatoes, the list goes on — can also help you reach those daily fluid goals. Aim to fill your plate with lots of vegetables and fruits since they “tend to be higher in water,” explains Figueroa.
Drink throughout the day: Don’t just wait until your next meal to sip on some water — keep at it all day long. And if you struggle to remember to drink, set a timer on your phone or use an app as a reminder.
Keep a refillable bottle close-by: Invest in a glass or stainless steel reusable water bottle (at least 12 to 18 ounces) so you can take water with you on the go, and aim to refill it four to five times during the day.
Sip through a straw: When you drink out of a straw, you might find that you're more likely to down more ounces. (At least that's the case for our Social Media Manager.) Not only can you swallow more at a time, but slurping through a straw also can make getting your fill of fluids more accessible. After all, you don’t have to waste any time opening and closing your bottle every time thirst strikes.
Listen to your body: By now you (hopefully!) know that if you’re thirsty, you should drink water. But there are other signs of dehydration that should signal to you it’s high time for H2O: dry skin and lips, fatigue, headaches, constipation, feeling dizzy or lightheaded and dark yellow urine (that “resembles apple juice,” says Brown.)