The body constantly loses water throughout the day, mostly through urine and sweat but also from regular body functions like breathing. To prevent dehydration, you need to get plenty of water from drink and food every day.
There are many different opinions on just how much water you should be drinking every day.
Health experts commonly recommend eight 8-ounce glasses, which equals about 2 liters, or half a gallon a day. This is called the 8×8 rule and is very easy to remember.
However, some experts believe that you need to sip on water constantly throughout the day, even when you’re not thirsty.
As with most things, this depends on the individual. Many factors (both internal and external) ultimately affect how much water you need.
This article takes a look at some water intake studies to separate fact from fiction and explains how to easily stay well hydrated for your individual needs.
How much water should you drink a day?
The daily four-to-six cup rule is for generally healthy people. It's possible to take in too much water if you have certain health conditions, such as thyroid disease or kidney, liver, or heart problems; or if you're taking medications that make you retain water, such as non-steroidal anti-inflammatory drugs (NSAIDs), opiate pain medications, and some antidepressants.
How much water a day should you drink if you fit into that category? There's no one-size-fits-all answer. Water intake must be individualized, and you should check with your doctor if you are not sure about the right amount for you.
But even a healthy person's water needs will vary, especially if you're losing water through sweat because you're exercising, or because you're outside on a hot day. If you're wondering how much water you should drink on those occasions, speak with your doctor, but a general rule of thumb for healthy people is to drink two to three cups of water per hour, or more if you're sweating heavily.