How many litres of water do you drink in a day? One? Two? Barely a glass? According to the NHS, we should all aim to drink 6 to 8 cups or glasses of fluid a day – and water, lower-fat milk and sugar-free drinks, including tea and coffee, all count.

But the answer to ‘How much water should you drink each day?’ isn’t that simple, and like everything nutrition-related, there isn’t one rule fits all – we all need varying amounts of water depending on our health, how active we are and where we live.

Here, then, is what you need to keep in mind when it comes to staying hydrated – ps. it’s not just about the quantity and quality of what you're sipping on....

How many litres of water should I drink a day?

So, how much water should we actually drink? Dr Joshua Berkowitz, founder of IVBoost Clinic, recommends drinking at least two litres, but also listening to your body.

‘Adults should be drinking at least 2 litres (8 glasses) a day, and up to 3 litres when the weather is hot and our body has to regulate the temperature. But various factors such as diet, climate, exercise levels and the state of health can all affect the amount of water and fluids we need to be drinking a day,’ he says.

You may need to drink more fluids if you’re:

  • pregnant or breastfeeding
  • in a hot environment – hot or humid weather can make you sweat more and requires additional fluid.
  • physically active for long periods – if you do any form of exercise or activity that makes you sweat, you need to drink extra water to cover the fluid loss.
  • ill or recovering from illness – your body loses fluids when you have a fever, vomiting or diarrhoea, which you'll need to replace.

Does this include fizzy water?

As mentioned, NHS guidance says that lower-fat milk and sugar-free drinks – including tea or coffee – count towards your recommended daily fluid intake. Sparkling water is included in this, which is just as hydrating as still water, however not all of the variations of the fizz-fuelled alternative are created equally. BANT registered nutritionist Eva Humphries explains that drinking sparkling or ‘fizzy’ water isn’t always the healthiest option.

‘Some natural sparkling mineral waters may be useful for rehydration since the minerals within them may act as electrolytes. Electrolytes are useful minerals that are crucial for fluid balance. On the other end of the spectrum, heavily carbonated water may cause gas and bloating in susceptible individuals,’ she says.

What happens if I don’t drink enough in a day?

Not drinking enough water leads to dehydration, which we all know about, but some people may be confused as to what it actually is. Dr Berkowitz explains that acute dehydration, from prolonged physical activity or heat exposure, can be cured with rest and rehydration, but dehydration can have serious effects.

‘Dehydration can have a huge impact on our health and organs. Signs you’re dehydrated include excessive thirst, dark strong-coloured urine, muscle tiredness, dizziness and light-headedness, dry mouth, lips, and eyes, passing urine less than four times a day or fatigue,’ he says. In extreme cases, dehydration can lead to seizures, kidney failure or brain swelling.

Is it possible to drink too much water?

With water being dubbed the healthiest drink for its purity, it’s easy to think that you can never have too much of it. However, overhydration can also have dire consequences, including brain swelling.

‘Apart from constantly needing the toilet, drinking excessive amounts of water, beyond what the body needs to function properly, can lead to a depletion in electrolytes. Over prolonged periods it can dilute the amount of sodium in the blood, impair kidney function and cause swelling of the cells,’ says Dr Berkowitz, as the kidneys can only remove 0.8 to 1 litres of water per hour. He recommends going to your doctor if you have a prolonged unquenchable thirst to ensure that there isn’t an underlying condition.

Professor Courtney Kipps, Consultant in Sports and Exercise Medicine, emphasises that overhydration can be a ‘medical emergency’ in some cases.

‘There is a potential risk of what’s called ‘hyponatraemia’ which means low sodium concentration as a result of the excess fluid diluting your blood sodium levels. It has been seen in athletes who have drunk too much during exercise, and in people who have taken illegal drugs which have caused them to become extremely thirsty,’ he explains.

How do I know if I'm drinking enough?

You know you’re drinking enough water if:

  • You rarely feel thirsty
  • Your urine is colourless or a very pale yellow

When should I drink water?

Believe it or not, there are ways to time your water drinking to have the best effect.

‘Typically, I tend to advise my nutrition clients to grab a glass of water first thing in the morning and drink water regularly throughout the day,’ says Humphries.

‘Studies indicate that drinking some water first thing in the morning may boost brain function and improve energy. There are no specific times that are outlined as the best to drink water, but finding a pattern that works for you is the most important thing you can do.’

For people who particularly struggle with drinking enough water, Humphries recommends ‘carrying a water bottle around as a visual cue. Paying attention to urine colour or the absence of urination may also be a good cue for drinking water.'

Adding to this, Professor Kipps highlights that water is still most likely the healthiest alternative to other drinks. ‘Sports drinks have similar risks as water and are not ‘better than water’ other than their carbohydrates which can be useful after prolonged exercise,’ he says.

The bottom line? To prevent dehydration and make sure your body has the fluids it needs, it's a good idea to drink a glass of water:

  • With each meal and between meals
  • Before, during and after exercise
  • If you feel thirsty

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2023-07-14T14:12:17Z dg43tfdfdgfd