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Q: How much water do I need to drink every day?

There are a lot of good reasons to stay hydrated. Healthy water intake can help with constipation, reduce your risk of kidney stones, and may even help you lose weight, while dehydration has been linked to headaches, fatigue, and impaired mood and concentration.

While the general advice is to drink two liters of water a day, or about eight glasses, the truth is that the amount of water you need depends on a lot of factors. If you’re exercising, sweating a lot or exposed to hot weather, or breastfeeding, it makes sense that you’ll need to replenish the fluid you’re losing by drinking more. At the same time, if you’re eating a lot of water-rich foods, like cucumbers and watermelon, you may not need to drink as much.

For most healthy people, the best way to make sure you are drinking enough is not counting how many glasses you are drinking, but simply by paying attention to your thirst. Your body will naturally tell you when you need more water by making you feel thirsty. Take a little extra care if you’re sick, such as if you’re having vomiting or diarrhea, and remind yourself to drink more in order to replace lost fluids.

If you’re tired of drinking plain water, other drinks can help you replenish your fluids, although it’s a good idea to avoid sugary drinks and sodas. And while you may have heard that caffeine is dehydrating because it’s a diuretic, that isn’t true -- so you can go ahead and drink coffee or tea as part of your daily fluid intake.

It is also important to note that some individuals may need to restrict their fluid intake in order to avoid problematic fluid accumulation in their body. For example, people with kidney failure or heart failure often need to limit fluids, even when it is hot outside or if they feel thirsty. Certain types of adrenal and endocrine disorders also require people to watch how much liquid they consume. Please talk with your physician or primary care provider about your individualized fluid intake needs if you have a condition that requires a fluid restriction.

Andrea De Roode
Clinical Dietitian