How much water should we be drinking in a day?

A majority of the human body is made up of water, which is why staying hydrated so important.

It can be confusing to determine how much the average person should drink in a day, especially in situations like when it’s hot outside or when you’re exercising. There are even consequences to not drinking the right amount of water, such as dehydration or overhydration.

The National Health Service (NHS) typically recommends drinking between six to eight glasses of fluid, including water, every day. But the US National Academies of Sciences, Engineering, and Medicine has determined that an adequate daily fluid intake is 15.5 cups (3.7 litres) per day for men and 11.5 cups (2.7 litres) per day for women. However, this fluid intake accounts for drinking plain water as well as other beverages and food that contain water, like fruits and vegetables.

The amount of water one should be drinking each day can also vary depending on the situation. According to the Mayo Clinic, those who are working out should be drinking extra water before, during, and after a period of exercise. This especially goes for any activity that makes you sweat, because drinking water helps replenish the fluid your body lost.

People in hot or humid weather should be drinking more water than usual because of how much they’re sweating, which contributes to fluid loss. Meanwhile, in areas with higher altitudes like the mountains, dehydration can become more common.

The Mayo Clinic suggests that people lose bodily fluids when they have a fever, are vomiting, or have diarrhoea. As such, it’s important that people are consuming extra water when they’re sick. Other conditions that might require increased fluid intake include bladder infections and urinary tract stones.

Feeling thirsty and passing dark-coloured, strong-smelling urine are some of the initial signs that you could be dehydrated. Other symptoms include feeling sluggish, feeling light headed, or having a dry mouth.

Drinking milk, water, and fruit juice is also a good way to maintain hydration. However, people should bear in mind the amount of sugar that can be contained in sweetened drinks. Tea and coffee may also help with hydration, though people should try to keep track of how much caffeine they’re consuming.

While it’s important to know whether you’re drinking enough water, the Mayo Clinic suggests it’s likely that nothing is wrong with someone’s water intake if they rarely feel thirsty and their urine is clear, or a light yellow colour.

It is possible to drink too much, however, it’s rarely a problem for someone with healthy kidneys. Still, overhydration can occur when the body retains or collects too much water. Some athletes who participate in endurance events, especially marathon runners, can be prone to taking on too much fluid. This can lead to water intoxication and dangerously low sodium levels, which is referred to as hyponatraemia. In order to help the body to relieve itself of excess water, as well as relieve pressure on the heart and other organs, doctors may prescribe diuretics or water tablets that promote the production of urine.