For years we have been told the rule of health: drink eight 8-ounce glasses of water every day. It is published in magazines, repeated by fitness influencers and likely told to you by a doctor at some point.
Here is a relaxed science-based and practical way to figure out how water you actually need to stay healthy and full of energy.
The Origins of the “Eight Glasses a Day” Misconception
Before we look at what your body needs it helps to understand why we are all so focused on the number eight. The story of the “8×8” rule is actually not very clear. Most nutritional historians say it started with a 1945 suggestion from the U.S. Food and Nutrition Board.
At that time the board said that people need 2.5 liters of water a day to function. However almost everyone ignored the sentence in that report that said most of this water comes from the foods we eat.
Water needs vary for each person.
The Key Factors That Actually Change Your Water Needs
So if eight glasses is not the number what’s ? The truth is that your daily water intake is always changing. It moves constantly based on things. Let’s look at the things that actually decide how water you should be drinking on any given day.
1. Your Body Size and Make-Up
Simply put bodies need water to work. Water is a part of our cells, tissues and vital organs. More body mass means more water is needed to keep everything working well. Also muscle holds water better than fat. If you have a lot of muscle your need for water will be higher than someone of the weight with less muscle. Your rate of metabolism also plays a role here; a faster metabolism makes heat and water is needed to help with temperature control.
2. Daily Physical Activity
This one seems obvious. It is very easy to not realize. When you exercise you lose water quickly through sweat and heavy breathing. A short 20-minute walk might not need you to drink a lot. An hour of lifting weights a long run or a tough hot yoga class definitely will. You have to replace what you lose. If you are very active your water needs will be higher.
3. Your Local Climate and Area
Living in a humid place means you will sweat more during the day even if you are just sitting outside or doing chores. Don’t be tricked by weather into thinking you can skip the water bottle. Dry winter air and indoor heating systems take moisture from your skin and lungs increasing your need for water without you feeling hot. High places also make your body lose water through breathing and more urination.
4. What You Drink
Your food affects your hydration. If your meals have a lot of processed, salty or very spicy food your body will need water to flush out the salt and keep blood pressure. On the hand if you drink a lot of drinks that make you lose water, like coffee, energy drinks with caffeine or alcohol you will lose fluids faster and might need a bit more plain water to balance it.
You Can “Eat” Your Water Too
One mistake with water tracking apps is that they completely forget about the food on your plate. You don’t just drink your water; you eat it too. Experts say that 20% to 30% of our water comes from food.
Think about your meals. Fruits like watermelon, strawberries, grapefruit and cantaloupe are full of water than 90% water by weight. Vegetables such as cucumbers, celery, zucchini, lettuce and spinach are mostly water.When you start counting the water in your meals meeting your hydration goals feels easier. You don’t have to carry a jug if you are eating a diet that has a lot of fruits and vegetables.
The Best Way to Check Hydration: The Urine Check
If you stop counting and delete the water apps how do you actually know if you are drinking enough? The answer is simple completely free and personal: look in the toilet bowl.
Your urine color is a real-time sign of your hydration. It works with your body perfectly giving feedback without any guessing or complicated math.
Light yellow: This is the standard. If your urine is the color of lemonade you’re fully hydrated. Your body has what it needs. Keep doing what you are doing.
Dark yellow: This is a warning. Seeing urine like this means your kidneys are working hard to save water. You are probably slightly dehydrated. You should probably drink a glass or two of water.
Clear: Believe it or not clear urine is not a prize. While it is not harmful it often means you are slightly overhydrated and flushing out electrolytes unnecessarily. You can comfortably drink a bit less.
Listening to your bodys thirst signals is also important. For adults the feeling of thirst is a sign. If your mouth feels dry you want some liquid drink. If you are not thirsty and your urine is yellow you are doing fine.
Special Cases: When to Drink More
While relying on thirst and checking your urine color works for people on a day there are times when you need to be more careful with your water.
When you are sick: Fevers, throwing up and having diarrhea take water away fast. During sickness you can’t always trust your thirst. You need to drink fluids with electrolytes to stop being very dehydrated and help your body fight the illness.
Breastfeeding: Your body is supporting another life. This special process needs blood, amniotic fluid and milk. This means pregnant and nursing moms need water than the average person.
As you age: As we get older our natural thirst feeling gets weaker. Older people often don’t feel thirsty when their body needs water. Because of this it can be helpful for older people to have a schedule to drink water than waiting for a signal that might not come in time.
A Quick Word on Electrolytes
It is also important to remember that real hydration is not about water. Your body needs electrolytes, like sodium, potassium and magnesium to actually take in the water you drink and move it into your cells where it is needed.
If you are drinking a lot of water. Not eating food or if you are sweating a lot during a marathon you can actually lower your sodium levels. This can lead to headaches, tiredness and in some cases a condition called hyponatremia. Always make sure your drinking habits are matched with a diet to keep your minerals balanced.
Make Hydration Flexible and Easy
At the end of the day hydration should never feel like a job. Worrying about ounces tracking every sip on your phone and feeling bad for missing a glass usually causes stress.
Start thinking of your water intake as a habit not a number you must reach. Listen to your body check your urine color and change your intake based on what you’re doing how hot it is outside. Pour yourself a glass when you feel thirsty enjoy your water, fruits and vegetables and finally stop feeling guilty, about the eight-glasses-a-day rule.Your body is a working machine that knows exactly what it needs; you just have to learn how to listen to the signs it is giving you.