Fluid intake: how much should you drink every day?
Are you aware of how much water you drink daily?
I’m sure you’ve been given the finger wagging advice to drink more water at some point in your life. Like much of the advice in the nutrition space, there is conflicting information about daily water intake. Between general “one-size-fits-all” recommendations and seemingly simple calculations based on body weight (that no one can ever remember), it can be confusing! Besides, where did the 8 cups per day recommendation even come from?
There is no reason to drown in the details, so let’s dive in and go a little deeper for the answers.
The most current research on how much fluid the average healthy adult living in a temperate climate needs on a daily basis is much higher than you’d expect: “The National Academies of Sciences, Engineering, and Medicine determined that an adequate daily fluid intake is: About 15.5 cups (3.7 liters) of fluids for men. About 11.5 cups (2.7 liters) of fluids a day for women” (1). That’s 124 ounces of fluid for men, and 92 ounces for women. Notice it says fluid intake, not water. Your coffee, tea, juice and other liquids count, which is good news since that’s a large amount of fluid to ingest for some folks. And most of us drink coffee, tea and other beverages in addition to water.
Water intake is important for a healthy brain, heart, skin, and for your metabolism. It should be a major part of your total daily fluid intake. Humans are made up of about 60 percent water, so it is a vital substance and it’s worth knowing the amount you need to function well. Being mindful of the total amount of fluids you drink per day will help determine what amount of water your body needs to function its best.
For example, if you drink 2 cups of coffee a day and a cup of tea, the average male would still need to drink 100 additional ounces of fluid, and the average female would need an additional 68 ounces of fluid! Even if you were one of the few people who drank 8 cups of water per day, you would still be in a deficit! If you exercise, spend time outside in the heat, or train as an athlete, you probably require even more fluids to avoid dehydration.
Research on dehydration discusses the strain it puts on vital organs and the strain it puts on the metabolism. Could this be the reason for your lack of energy, brain fog, and irritability? Dehydration can also make you feel like you’re hungry when you’re thirsty, and that’s why staying hydrated can be a powerful weight loss driver (2). If you are well hydrated you may notice less hunger and better energy throughout the day. Getting enough fluids can also keep you regular while simultaneously supporting detoxification by flushing out toxins through your urine.
Although rare, there is the chance of overhydration. It is rare because our bodies will increase urine output if we’re getting too much fluid (translation: you’ll be visiting the bathroom more often). However, drinking too much water in a short period of time and not letting your body catch up can be dangerous because that lowers electrolyte levels in the body, like sodium. Signs of overhydration may be as simple as increased bathroom visits; however, lower sodium levels can lead to serious symptoms like headaches, nausea, vomiting, confusion, disorientation, cramps, and muscle weakness.
So, how do you drink more water to stay hydrated throughout the day? Start by tracking the amount of fluids you actually drink daily. Include all liquids for a decent estimate. Then, check in with yourself and see how you feel. Maybe you’re good to go and no changes are necessary. Or you find that you drink water in the morning but then you get busy the rest of the day and forget to drink anything more.
Use a container that easily allows you to track and measure the amount of water you drink, and then see how many times a day you refill it. Take a bottle of water with you to the gym or on a walk. Start a routine where you drink a glass of water prior to a meal. Remember, all fluids matter but plain water is the best!
References
1. http://www.nationalacademies.org/podcast/0309091691.rm
2. https://pubmed.ncbi.nlm.nih.gov/9972188/
