How Much Water Should You Drink In a Day?Nov. 20, 2019 - Katie McCallum
Ever feel like your water bottle is staring at you? It’s right next to you, it’s full — but you grab another can of soda instead. Cue the wave of guilt.
Let’s be honest, sometimes drinking water can feel like a chore. But knowing how much water you actually need and why it’s so important to stay hydrated may be just what you need to help you hit your daily water goal — every day.
“Hydration is essential for so many functions in your body,” says Amanda Beaver, wellness dietitian at Houston Methodist. “Water helps support brain function, your heart pump blood to your muscles, regulate your body temperature, prevent constipation, and the list goes on.”
You’re constantly losing water through your breath, sweat, urine and bowel movements — so it’s important that, throughout the day, you’re replacing the water you lose.
How much water should you drink a day?
You’ve probably heard the 8x8 rule: Drink eight 8-ounce glasses of water every day.
It’s a simple rule to remember, but it may be too simple in practice. That’s because everyone’s daily water needs are different, and they vary based on:
- Your gender – men generally need more water than women
- Your age – children and elderly individuals can be less aware of thirst
- How much you’re sweating – whether it’s due to hot weather or exercise, you lose water when you sweat
- Your health – water loss increases during illnesses that cause vomiting or diarrhea, as well as during pregnancy, breast-feeding and as a result of some medical conditions
- Medications you’re taking – some medicines cause fluid retention, while others cause excessive urination
Even though several factors affect how much water we each need, the Institute of Medicine recommends that men get about 3.7 liters of fluid per day and that women get about 2.7 liters of fluid per day.
“That may sound like a lot of water, but not all of it has to come from beverages — some of it can come from food,” explains Beaver. “Most people get about 20% of their daily water intake from the fluid in the food they eat every day.”
With this in mind, the amount of water you should aim to drink per day is more like:
- 13 cups of water for men
- 9 cups of water for women
What are the symptoms of dehydration?
Whether it’s falling short of your daily dose of water, or forgetting to add an extra glass after exercising, drinking too little water throughout the day has consequences.
Dehydration can reduce physical performance
Beaver says that even being just mildly dehydrated can impact your endurance and physical performance. It can also increase your perceived effort, which can be particularly frustrating while exercising.
Dehydration impacts cognitive function
Getting behind on water can also affect your performance at work, school or home — since being dehydrated reduces concentration, alertness and short-term memory.
Dehydration is linked to headaches
If you find yourself with a bad headache during the day, one question to ask yourself is: Have I been drinking enough water? Lack of water can also be a trigger for migraines.
(Related: Why Do I Keep Getting Headaches?)
The good news is that identifying dehydration is pretty easy.
“One of the best indicators of hydration status we can use is the color of our urine,” says Beaver. “If you look at your urine and it’s a pale yellow or straw-colored, it’s a sign that you’re adequately hydrated. But, if your urine is darker than that, it likely means you’re that you need to drink more water.”
Video: Why is it important to stay hydrated?
Does water boost metabolism?
There’s a reason that water makes up 60% of your body weight — your body depends on it to survive.
Aside from the many essential roles water plays in your body, there are added health benefits to drinking enough water.
“Some studies have shown that drinking a bottle of water can temporarily boost our metabolism for about 30 minutes to an hour,” says Beaver. “And drinking a bottle of water 30 minutes before a meal can reduce how much we end up eating at that meal — likely because we feel fuller.”
How to stay hydrated in 5 tips
If drinking water still feels like an impossible chore, Beaver recommends the following tips:
- Find a water bottle you really like and carry it around with you as often as possible (and remember to clean your bottle frequently).
- Drink a glass of water as part of your morning routine.
- Try unsweetened sparkling water or add fresh fruits, vegetables and herbs to your water (Beaver’s favorite combination is cucumber with lime).
- Snack on foods that contain a lot of water, like cucumbers, celery, watermelon, strawberries and oranges.
- Sip on water throughout the day, not just during meals (this is where carrying around that water bottle you like comes in handy).
Beaver’s last tip is especially important since water loss happens throughout the day.
“It’s important to evenly distribute your water intake throughout the day,” says Beaver. “If you try to over-compensate in the morning or catch up on water at the end of the day, it doesn’t undo the fact that you were dehydrated most of the day.”