How much water should you drink a day? - goal-water

How much water should you drink a day?

A commonly cited statistic is that 75% of adults may suffer from chronic dehydration.

Many of us overlook hydration when trying to pursue a healthy lifestyle. We place an overemphasis on diet and exercise, the symptoms of dehydration are subtle and easily mistaken for hunger or fatigue, and we see water as bland compared to other (often sugary) beverages.

Without a structured approach and plan to drink water, hydration tends to fall by the wayside.


Why do we need water?

About 60% of your body weight is water. It is not merely a dietary requirement but a fundamental necessity for maintaining the intricate machinery of life. It is the medium in which all cellular processes occur, including the transport and biochemical reactions of nutrients. It is imperative for the digestion and absorption of food. It flushes out toxins, cushions your joints, and regulates your temperature - the list goes on and on.

With only a 1-2% water deficit, you can become dehydrated. Severe cases of dehydration can cause dizziness, confusion, and even seizures.


Glass of clear water on table


What are the benefits of drinking water?

Water can improve many areas of your health:

  • Optimal brain function: proper hydration enhances the ability to concentrate, maintain attention, and support short-term and working memory. Additionally, it can positively influence mood by preventing anxiety, irritability, and stress. Conversely, dehydration is a known trigger for headaches and migraines.
  • Enhanced physical performance and endurance: the American College of Sports Medicine reported that athletes experiencing fluid loss equivalent to 2% of their body weight had diminished aerobic capacity and stamina. Also, hydration facilitates thermoregulation, enabling athletes to maintain core temperature and optimise performance.
  • Improved weight management: a study published in the Journal of Clinical Endocrinology and Metabolism observed a 30% increase in metabolic rate following the consumption of 500 ml of water. Additionally, individuals who consume two cups of water before meals experience greater weight loss, as water makes you feel full.
  • Improved skin health: adequate hydration contributes to maintaining moisture, elasticity, and a youthful appearance of the skin, while also playing a role in reducing skin problems and enhancing healing processes. A study in the International Journey of Cosmetic Science found that drinking 2.25 litres of water per day for four weeks altered skin density and thickness, leading to improved skin hydration.
  • Reduced constipation and improved digestion: adequate water intake keeps the gastrointestinal tract moving by aiding in the breakdown and passage of food, which can help prevent constipation. Water is also a necessary component of digestive juices that help digest and absorb nutrients from the food we eat.
  • Detoxification and renal function: the risk of kidney stones decreases with increased water consumption; it is reported in the Journal of the American Society of Nephrology that individuals drinking more than 2.5 litres of water per day had a 40% reduced risk of stone formation compared to those consuming less than 1.2 litres.
  • Joint lubrication and cushioning: staying well-hydrated is thought to contribute to overall joint mobility and to help alleviate joint pain through the maintenance of synovial fluid. Even mild dehydration could potentially affect this balance, leading to joint pain or exacerbating conditions such as arthritis.


How much water should you drink a day?

Calculating the amount of water you should drink a day is more complicated than you may think. That’s because hydration needs are far from one-size-fits-all.

In general, the US Institute of Medicine suggest the following:


Age Recommended fluid intake/day
Adult male 18+ 3.7 litres
Adult female 18+ 2.7 litres
Boys 14-18 3.3 litres
Girls 14-18 2.3 litres
Boys 9-13 2.4 litres
Girls 9-13 2.1 litres
4-8 years 1.7 litres
1-3 years 0.9 litres
Pregnant women 18+ As above +0.3 litres
Breastfeeding women 18+ As above +1.1 litres


Typically, 80% of people's total water comes from drinking water and beverages and the other 20% is derived from food. Hence, it is important to interpret the above numbers accordingly.

However, to be more accurate you can adjust your suggested fluid intake by considering various factors:

  • Body weight: people with more body surface area and muscle mass require more water intake.
  • Diet: certain foods have a high water content such as fruits, vegetables and soups. Hence, a lower intake from water and beverage is needed.
  • Activity level: if you are active during the day or walk or stand a lot, you’ll need more water than someone who’s sitting at a desk. When you exercise you lose water through sweat and therefore should increase your water intake to cover the water loss.
  • Age: as we age, our bodies may require more water to combat the natural decrease in kidney efficiency and changes in body composition.
  • Environment: hot or humid weather can make you sweat more, necessitating additional fluid intake. High altitudes may also increase your need for water.
  • Overall health and medications: if you have an infection or a fever, or if you lose fluids through vomiting or diarrhoea, you will need to drink more water. If you have a health condition like diabetes or are taking diuretics, you will also need more water. However, it is 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 nonsteroidal anti-inflammatory drugs (NSAIDs), opiate pain medications, and some antidepressants. If you have health conditions or are on certain medication you should consult your doctor about your recommended water intake.
  • Pregnancy or breastfeeding: higher water intake is required to maintain amniotic fluid levels and for milk production. Your body is doing the work for two (or more), after all.



How to calculate how much to drink per day?

To accurately assess how much water you should drink per day use this hydration calculator.

Follow 3 easy steps to see whether you are drinking enough water. “Your hydration status” will tell you how much water you should be drinking per day to balance the water you lose and the water you get from foods.


Do liquids other than water count?

Water is not your only choice when it comes to hydration. All beverages containing water contribute toward your daily needs, but they often can be high in sugar and calories:

  • Coffee and tea: have water but also contain caffeine, which may have a mild diuretic effect causing the loss of water through urine. Caffeine can also make you feel jittery.
  • Alcoholic drinks: have water, too. But like caffeine, they can cause you to lose water through your urine.
  • Soft/fizzy drinks: are typically high in sugars and calories with can lead to weight gain, diabetes and heart disease.
  • Sports drinks: bottled sports drinks and powders have a high water content. They also contain carbohydrates and electrolytes, which can help you absorb water and keep your energy levels up. During intense workouts, they help to replace salt lost through sweat. But be careful: many also contain lots of extra calories, sugar, and salt – hence you should limit the amount you drink.
  • Energy drinks: they contain sugar, high calories as well as caffeine - often in high doses. Many doctors recommend that children and teens avoid them.

Of course, there are many reasons why water is still the better choice – it is healthy, free, and readily available. But many of us find plain water tasteless and therefore don’t drink enough.

We think that elevating your water with tasty GOAL water hydration tablets is the perfect solution to achieve your target water intake. After all, they have delicious taste, are easy to carry around, have zero calories and are sugar-free.



When should you drink during the day?

  • First thing in the morning: you’re fasting the entire time that you’re asleep - and, often, for a few hours before sleep. So your stomach is empty and you’re dehydrated when you first wake up. Drinking water first thing in the morning helps your body recover from its nightly dehydration. Your body absorbs water faster when your stomach is empty. In Japan, there’s a tradition of drinking water on an empty stomach for good health.
  • At regular intervals such as every hour: thirst is actually a sign of dehydration, so if you feel thirsty, you have some catching up to do! In other words, it is important to pre-hydrate - drink before you start feeling thirsty, or before you do an activity.
  • Before, during and after exercise: as your body need to be hydrated for optimal performance and to cover the water losses from sweating. Here are some basic guidelines from the American Council on Exercise:
    • 2-3 hours before exercise: drink 400-500ml of water to ensure you are adequately hydrated.
    • Immediately before or during your warm up: 500ml of water.
    • During exercise: drink 200-300ml of water every 10 to 20 minutes during exercise.
    • Within 30 minutes after exercise: drink 300ml ounces of water no more than 30 minutes after you exercise.

Athletes may want to measure how much fluid they lose during exercise to get a more specific measurement of how much water to drink. For intense exercise over long periods or in hot weather, electrolyte solutions to replace lost salts are recommended.


How to know if you are dehydrated?

Thirst, passing dark-coloured urine and less frequent urination are key signs that you may be dehydrated, as well as feeling lethargic, weak as well as having a dry mouth and lips. Dizziness, headaches, rapid heartbeat and confusion are late symptoms of dehydration – if you experience these you should increase your water intake quickly.

Note that babies, children and the elderly are most at risk of dehydration.

The most practical way to know if you are dehydrated is to monitor your urine. If you are adequately hydrated, you should be urinating about once every two to four hours, and your urine should be colourless or a very pale yellow (the colour of hay or lighter). If it is darker than that, you haven’t had enough fluid. See the chart below for reference:



What are some practical tips to drink more water?

There are some small changes you can make to your routine that will have a big impact of your water intake:

  • Carry a water bottle: always have a water bottle with you, whether you're at home, at work, or on the go. This makes it easier to drink water throughout the day.
  • Set reminders: use your phone or smartwatch to set reminders to take a sip of water every hour or so; alternatively, there are apps available to track and record your water intake.
  • Flavour your water: if you find plain water unappealing, try adding a hint of flavour with GOAL water tablets.
  • Drink before every meal: make it a habit to drink a glass of water before each meal. This not only helps with hydration but can also aid in digestion and satiety.
  • Eat water-rich foods: include fruits and vegetables with high water content in your diet, like watermelon, cucumber, oranges, and lettuce.
  • Replace other drinks with water: try to substitute sugary or caffeinated beverages for water.
  • Drink water after bathroom breaks: rehydrate after using the bathroom to replenish your fluids.
  • Start and end your day with water: make it a routine to drink a glass of water when you wake up and before you go to bed.
  • Drink more during exercise: always hydrate before, during, and after exercise to replace fluids lost through sweating.



Can you drink too much water?

It is possible to drink too much water, a condition known as water intoxication or hyponatremia (low sodium in the blood). This occurs when the balance of electrolytes in your body is disrupted by a large intake of water. The symptoms can include headache, confusion, nausea, vomiting, fatigue, muscle weakness, cramps and seizures.

Listening to your body's thirst signals and being mindful of your total fluid intake, especially during high-intensity activities and in extreme heat, is key. If you suspect that you or someone else is experiencing symptoms of hyponatremia, seek medical attention immediately. 

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