Staying hydrated is big business these days – from the Stanley water bottles that have taken up residence on Gen Z nightstands to the “smart” waters lining the shelves in your local Sainsbury’s. And while for a very long time “drink eight glasses of water a day” was the rule of thumb, dietician, author and King’s College London scientist, Dr Emily Leeming, points out that this is essentially an arbitrary number, and not a benchmark based on any real evidence.
“We each have different fluid needs based on the size of our bodies, and our own needs can change day to day too,” she explains. “That can include how hot the weather is, how much salty food you’ve eaten and how much exercise you’ve done.” During the summer, when temperatures rise, you’ll need to drink more water than on a similar day during winter. In the UK, 60 per cent of people drink less than a single glass of water a day while 75 per cent of Americans are chronically dehydrated. Whatever your personal metrics, that isn’t enough.
How much water should you drink a day?
While eight glasses a day might be a “quasi” fact, drinking more than one glass a day is obviously the goal. A more accurate guideline is to aim for 1.5 to 2 litres a day, a recommendation backed up by the British Dietetic Association. This number changes if you are pregnant, active or spending time in warm or hot weather.
A simple way to keep tabs on how much water you’re drinking is with a reusable water bottle marked with a millilitre volume indicator. It’s straightforward enough to figure out how many refills will get you to the 1.5 to 2 litre mark. The popular Stanley Quencher Tumbler holds 1.8 litres of liquid, making it an easy, one-and-done option.
Signs of dehydration
Signs that you’re dehydrated include headaches, thirst and difficulty focusing – even a two per cent loss in hydration can make you feel tired and sluggish – but Dr Leeming says the best way to assess is by looking at the colour of your urine. “When you’re hydrated, your wee will be the colour of translucent, pale lemonade,” she explains. “When you need to drink more, it will be dark yellow – apple juice colour or darker. And when you’re drinking too much water, it will be completely clear.”
Signs of mild dehydration include:
- Extreme thirst
- Dry or sticky mouth
- Tiredness
- Headache
- Dizziness
- Less frequent urination
- Dark urine
Signs of severe dehydration include:
- Extreme dizziness
- Confusion
- Little to no sweat
- Low blood pressure
- Rapid heart rate
- Sunken eyes
If you are experiencing any of these symptoms, seek immediate help.
How to increase your water intake
Instead of counting your glasses, commit to keeping tabs on your urine and acting accordingly. “Hydration doesn’t have to come in the form of just water, either – coffee and tea count too,” she adds. “When it’s hot, you can add herbal teas to cold iced water instead of hot, for a cool flavoured drink.” Other ways to add interest to your water include adding slices of lemon, cucumber, mint or basil, or try Artah’s Cellular Hydration, which is packed with electrolytes to supercharge your hydration status, or Ancient & Brave’s True Hydration. (Electrolyte supplements work by replenishing minerals lost through sweat that help to regulate fluid balance within the body.)
Another easy hydration hack is to concentrate on eating water-rich foods. Cucumber, lettuce, tomatoes and radishes all contain a high percentage of water, making them secret hydration heroes. In hot weather, loading up meals with a variety of high-water-content foods can make hitting your daily quota less of a chore. They come with the added benefit of containing antioxidants, fibre and a range of vitamins, minerals and micronutrients. Cucumber, for example, is made up of 96 per cent water, as well as containing vitamin C.