“Water is life.” You’ve probably heard this statement at least once. But as much as it’s almost certain that you’ve heard it, it’s also quite certain that you haven’t stopped to really think about what those three words actually mean, especially when it comes to healthy living.
You see, there’s a whole lot that water does beyond just quenching our thirst. That’s why health professionals so often remind us to drink enough water. And, admittedly, it can sometimes sound like the same boring advice repeated over and over again. But there’s a reason hydration gets so much attention: there’s a reason water is considered so important to our health, and that’s what we want to talk about.
In this article, we’ll look at the role of water in our daily health, how much fluid people actually need, and how our hydration needs can differ by age and activity level. We’ll also consider where drinks such as coffee, juice, and soda fit in the whole hydration conversation. Let’s dive right in!
What Does Water Actually Do for Our Body?
Here’s a quick perspective shift before we actually get into the different roles water plays in our bodies. Think about how long the average person can survive without food and without water? The answer should give you a slightly different perspective on just how important hydration is.
Well, science suggests that a normally nourished person can survive for several weeks without food. Some sources put it at around 3 weeks, and some at 8 weeks. It depends on the individual and circumstances.
However, severe dehydration can become life-threatening within days. Some sources even say a person can generally survive for only about 3–5 days without water. The exact timeframe also varies depending on factors such as temperature, physical activity, illness, and how much fluid the person is losing.
Now, this isn’t to say that water is more important than food, because we need both. But it helps to create a perspective shift on how really important water is, and the fact that it plays other key roles in our survival beyond the fact we usually just use it to quench our thirst or drink it alongside a meal.
Here are some of the key roles that water plays in the body:
Water Helps Regulate Body Temperature
Water plays a role in regulating the body temperature. When you get hot, particularly during exercise or in warm weather, your body produces sweat. As that sweat evaporates from your skin, it helps carry heat away from the body and cool you down.
This is why staying hydrated is particularly important when you’re sweating heavily. Losing too much fluid without replacing it can interfere with your body’s ability to regulate its temperature and, in severe cases, contribute to dangerous heat-related illnesses.
Water Helps Transport Nutrients and Oxygen
The blood is made up of roughly 50% to 55% water, which helps it remain fluid enough to circulate around the body. Through this circulation, blood can transport oxygen and nutrients to cells and tissues that need them. In other words, water in your blood stream supports the circulation of nutrients and oxygen around the body.
Water Supports Digestion
Water also plays an important role in digestion. Your body needs fluids to help break down and process the food you eat. In other words, what you eat is important. But regardless of what you eat, your body needs enough water to process and move that food through the digestive system.
Water Helps Your Body Get Rid of Waste
The body is constantly producing waste that needs to be removed, and water plays an important part in that process. Specifically, the kidneys filter the blood and produce urine, which helps remove waste and excess substances from the body. Adequate hydration supports this process by providing the fluid your kidneys need to do their job.
Water also helps keep your bowel movements regular by making your stools softer and easier to pass.
Water Helps Keep Your Joints and Tissues Working
Water also contributes to the normal function of the joints. Specifically, water helps lubricate your joints, allowing them to move smoothly. It also helps cushion and protect sensitive structures, including the brain and spinal cord.
What Happens When You Don’t Drink Enough Water (Hydrate Properly)
The body is constantly losing water. You lose fluids when you urinate, sweat, breathe, and have bowel movements. On a normal day, these losses are simply part of how the body works, and you replace them by drinking fluids and getting some water from the foods you eat.
However, when fluid losses become greater than the amount you replace, your body can become dehydrated. This can happen after heavy exercise, prolonged exposure to heat, or during illnesses involving vomiting, diarrhea, or fever.
So, what happens when you continually lose more fluid than you replace?
Here’s an outline of how dehydration can progress, starting with the earliest and mildest signs and gradually moving toward more severe complications:
- Thirst: Your body’s first and most obvious signal that it needs more fluid is often an increased feeling of thirst.
- Dry mouth and darker urine: As your body tries to conserve water, you may notice a dry mouth and produce less urine. Your urine may also become darker and more concentrated.
- Tiredness and weakness: As dehydration progresses, you may begin to feel unusually tired, weak, sluggish, or less able to concentrate.
- Headache and dizziness: Losing more fluid can affect circulation and blood pressure, which may leave you feeling dizzy or lightheaded and can sometimes contribute to headaches.
- Reduced physical and mental performance: More significant dehydration can make it harder to think clearly, concentrate, exercise, or perform normal physical activities.
- Low blood pressure and rapid heartbeat: With substantial fluid loss, the amount of blood circulating through your body can fall. Your heart may then beat faster to help maintain circulation, while blood pressure can drop.
- Electrolyte imbalance: Continued fluid loss can disturb the balance of minerals such as sodium and potassium. This can affect muscles, nerves, and other essential body functions.
- Kidney problems: Severe dehydration reduces blood flow to the kidneys and, if left untreated, can contribute to acute kidney injury.
- Confusion and loss of consciousness: As dehydration becomes severe, reduced blood flow and electrolyte disturbances can affect brain function, potentially causing confusion, extreme drowsiness, or loss of consciousness.
- Shock, organ failure, and death: At its most severe, dehydration can cause dangerously low blood pressure and shock. Without urgent treatment, this can lead to organ failure and can ultimately be fatal.
And these bring us back to where we started. Water may seem like the simplest thing we consume each day, but its role inside the body is anything but simple. It helps regulate temperature, transport important substances, support digestion, remove waste, and keep numerous tissues and organs functioning properly.
So when someone tells you to “drink more water,” they’re not just giving you another piece of generic healthy-living advice. They’re reminding you to replenish something your body is constantly using and losing.
How Much Water Do You Actually Need Each Day?
Now that we’ve established the roles water plays in the body and how important it is to continuously stay hydrated, that is, to drink enough fluids, the next most logical question is probably: How much should I actually drink?
Over the years, there have been all kinds of recommendations and advice about how much water people should consume. You may have heard someone say you should drink a certain number of litres every day. Someone else may also tell you to drink eight glasses.
The truth, however, is that there isn’t necessarily one universal rule that works for everyone. How much fluid you need can vary from person to person and depends on several factors, including your age, how physically active you are, the weather and climate around you, and your current health.
Hydration Needs by Age
Our bodies and lifestyles change as we move through different stages of life, and so can our hydration needs. This is why the required level of hydration we need varies from children to adults.
- Children: Children aged 4-8 generally need around 1.6 litres of total water per day, while those aged 9-13 may need roughly 1.9-2.1 litres. This includes water from food and beverages. And actual needs can vary with body size, activity, weather, and diet.
- Teenagers: Teenagers aged 14-17 generally need around 2.0-2.5 litres of total water daily. Active teenagers who play sports or exercise regularly may need more because of increased fluid loss through sweat.
- Adults: Adult women generally need around 2.0 litres, while adult men need around 2.5 litres of total water per day. However, body size, physical activity, climate, diet, and health can all affect individual needs.
- Older adults: Older adults generally have similar fluid needs to other adults, around 2.0-2.5 litres of total water daily. But as thirst perception lessens with age, seniors have to be mindful to drink regularly.
Physical Activity
Exercise increases fluid loss through sweating, so active people may need more than their usual daily amount. Someone doing light activity may need little adjustment, while someone exercising intensely or for long periods may need significantly more. How much more depends on factors such as exercise intensity, duration, temperature, and individual sweat rate.
Weather and Climate Matter
Your environment can also change how much fluid your body needs. Hot and humid conditions can increase fluid needs because the body loses more water through sweating. Someone working or exercising outdoors in hot weather may therefore need more than the usual 2-2.5 litres of total water per day. The exact amount depends on the temperature, humidity, activity level, and how much they sweat.
Health and Illness
Your hydration needs can also change when you’re unwell. For example, illnesses involving vomiting, diarrhea, or fever can increase fluid losses and therefore increase hydration needs. There isn’t a fixed amount that applies to everyone in these situations; the amount needed depends on how much fluid is being lost and the severity of the illness.
So, How Much Should You Drink?
By now, you can probably see why there isn’t a simple “everyone should drink X litres of water every day” answer.
There are general recommendations that can provide a useful starting point. But your actual needs can be higher or lower depending on age, activity, weather, diet, and health. For most healthy people, thirst is a useful everyday signal, but during intense exercise, hot weather, or illness, you may need to pay closer attention to your fluid intake.
So, rather than obsessing over a particular number, think of hydration as something you maintain throughout the day.
Does Everything You Drink Count Toward Hydration?
When we talk about staying hydrated, it’s easy to assume that only plain water counts. As mentioned earlier, that’s not quite how hydration works. Your body gets fluids from a variety of drinks, and even some of the foods you eat contribute to your daily fluid intake.
So, where do some of our everyday drinks, like coffee and tea, Juice, and soda, fit into the picture?
Coffee and Tea
Yes, coffee and tea contribute to overall fluid intake. Their caffeine content doesn’t automatically cancel out the water they contain or mean that they will dehydrate you.
However, caffeine can have a mild diuretic effect, that is, it can make you urinate more frequently and cause your body to lose some fluid, particularly in larger amounts. That doesn’t mean you need to avoid coffee or tea to stay hydrated, but moderation still makes sense, especially if you’re consuming several caffeinated drinks throughout the day.
Juice
Juice also contributes to fluid, but it doesn’t mean they are a great alternative. This is because they also contain substantial amounts of sugar. Drinking large amounts regularly can therefore add a significant amount of sugar and calories to your diet.
Whole fruit, on the other hand, gives you water along with fiber and other nutrients. So while a glass of juice can contribute to hydration, it doesn’t necessarily offer all the nutritional benefits of eating the fruit itself.
Soda
Soda contains plenty of water, so technically, it contributes to your fluid intake too. But that doesn’t necessarily make it the best everyday hydration choice, either.
Regular soda also contains a lot of added sugar, meaning you may be taking in considerable amounts of sugar and calories while trying to quench your thirst.
So, What Should You Drink Most Often?
The simple answer is that water is an excellent go-to choice. It’s readily available, contains no added sugar or calories, and provides the hydration your body needs.
That doesn’t mean coffee, tea, juice, or even soda suddenly stop counting toward your fluid intake. They can all contribute to hydration. The bigger picture is that what you drink affects more than just your hydration, so water is generally the simplest choice to make most of your everyday fluid intake.
How Can You Tell If You’re Not Drinking Enough?
Your body will give you several clues, and here are some of the common signs to pay attention to:
- Thirst
- Dark yellow (concentrated) urine
- Dry mouth
- Unusual tiredness or sluggishness
- Headache
- Dizziness or lightheadedness
- Reduced urination
Keep in mind that these symptoms don’t automatically mean you’re dehydrated, as they can have many other causes. However, if several occur together, particularly after heavy sweating, exercise, vomiting, diarrhea, or prolonged exposure to heat, it’s worth paying closer attention to your fluid intake.
Simple Ways to Stay Hydrated Throughout the Day
Staying hydrated doesn’t have to be complicated. Here are a few simple habits that can make it easier to get enough fluids throughout the day:
- Keep water within reach
- Drink regularly instead of waiting until you’re very thirsty
- Have a glass of water with meals
- Carry a reusable water bottle
- Drink more during exercise or hot weather
- Include water-rich foods such as fruits and vegetables in your diet
- Choose water more often instead of sugary drinks
Why What You Drink Matters Too
The statement “Water is life” may sound like a cliché, but as we’ve seen, there’s a good reason behind that statement. Water does far more than quench your thirst. It helps regulate body temperature, transport nutrients, support digestion, remove waste, and keep various parts of the body functioning properly.
So at the end of the day, healthy living isn’t just what you put on your plate. It’s also about what you put in your glass.