If you're drinking eight 250ml glasses of water a day, you're doing fine, but you could probably benefit from a few tweaks.
With branded bottle trends and daily challenges on TikTok, hydration is all the rage, and that's good news for your health. The average human body is made up of over 60% water. Water makes up nearly two-thirds of your brain and heart, 83% of your lungs, 64% of your skin, and even 31% of your bones. It is involved in almost every process that keeps you alive.
"Water is essential for your body's survival," says Crystal Scott, dietitian-nutritionist. "It helps regulate your temperature, transports nutrients, removes waste, lubricates your joints and tissues, and also plays a crucial role in maintaining the delicate balance of electrolytes and fluids in your body."
You lose water when you breathe, sweat, urinate, and metabolize food and drink into energy. If you don't replace this fluid, your health can deteriorate rapidly. Without food, your body can continue to function for three weeks or more. But without water, you will die in just a few days. There are just too many systems that depend on it.
"That's the starting point when looking at any form of change or issues with your nutrition or lifestyle – assess your water intake first and foremost," Scott says. "It helps give signals of satiety, it can improve cognitive function, mood, physical performance, and can prevent health problems like constipation, kidney stones, and urinary tract infections. It's the one of the fundamental pillars."
The general rule you've probably heard is the 8x4 rule: Drink eight quarter-liter (250 ml) glasses of water a day. If you hit that target, you're doing well, Scott says. But it is possible that you could benefit from some adjustments. "I don't think that quantity is necessarily wrong, but I think the research over time has certainly evolved," she says. “Water recommendations are going to vary based on age, gender, and activity level.” Your needs may also vary depending on your life circumstances.
Average daily water intake recommendations are around 3.7 liters for men and around 2.7 liters for women. If you're not drinking exactly that amount each day, you're probably close to or even above it because you also get water from food, Scott says. "You can get a lot of hydration from foods like celery, oranges, strawberries, watermelon, and cucumbers," she says. "These are all hydrating foods that can actually help supplement your water intake."
Although rare, it is possible to drink too much water. It's a condition called hyponatremia, and it happens when the amount of water in your system overwhelms your kidneys and they can't maintain a normal filtration rate. The sodium content of your blood becomes dangerously diluted and causes your cells to swell. Certain health conditions like kidney failure and congestive heart failure put you at higher risk, and some top athletes may experience this.
But for the majority of the population, the major problem is getting enough water. While it's helpful to keep an eye on the actual amounts, the best indicator of how hydrated you are is your body. When you don't drink enough water, your body will show certain signs.
“The color of urine is a very good indicator of hydration status,” Scott says. If your urine is pale yellow or clear in color after urinating, great. Dark yellow or amber colored urine indicates that your body needs fluids. Headaches, migraines, poor sleep, constipation, dizziness, and feeling lightheaded or confused can also be symptoms of dehydration. If in doubt, head to the faucet.
If you're committing to optimizing hydration, Scott recommends starting slow. First, take stock of where you are, then set a goal for where you want to be.
"A good starting point is to divide your weight in pounds by 35 to get the number of liters of water per day," she says. "So for someone who weighs 200 lbs, a first target would be 2.5 litres. If that person is only drinking 600ml of fluid per day, each week you would need to increase to around 250-300ml per week, slowly but surely. Because if you hydrate too quickly, you can feel really waterlogged."
Other helpful tips Scott suggests: Experiment with drinking the water ice cold or adding sliced fruit to flavor it. Use smaller water bottles and refill them rather than filling a huge jug for the whole day, which can seem daunting. Break your day into chunks and give yourself a mini-goal in each section. This way you maintain a constant flow of hydration instead of trying to swallow it all at once.