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The biggest hydration myths busted – from caffeine to #WaterTok
Written byAmy Bonifas
Reviewed byLeila Weller-Kis
Does flavouring your water help you drink more? Is bloating caused by drinking too much? Our nutritionist gives us every last drop about staying hydrated
Summary
1Myth: Everyone needs eight glasses of water a day
“While the general guidelines suggest six to eight glasses, the exact amount of water varies...
2Myth: Darker pee means you're not drinking enough
Yes, the colour of your pee is a great indicator of whether you’re dehydrated or not...
3Myth: You can't drink too much water
“It’s rare, but it can happen,” says Leila. Glugging too much water can cause overhydration...
In an age where our water bottles are big and our thirst for health hacks is even bigger, it can be hard to get to the source.
While some people religiously track their drinking in apps or journals, many of us still don’t drink enough. According to a recent survey by flavoured water bottle brand Air Up, 45% of Brits drink only one glass of water daily.
“Water's key in converting food into energy, managing blood sugar, flushing out toxins – and it also impacts things like concentration and memory,” begins nutritionist Leila Weller-Kis.
With so much misinformation around how to hydrate, Leila dives into the ocean of water myths to come up with the truth.
“Listen to your body – it usually tells you when you’re thirsty and what you need”
Myth 1: Everyone needs eight glasses of water a day
There actually isn’t a one-size-fits-all approach. “While the general guidelines1 suggest six to eight glasses, the exact amount of water varies from person to person. It can depend on your sex, age, body composition and activity levels, which can vary day by day.
“Women might need to drink a little less and men a bit more,” says Leila. “On days when you’re exercising or training, you’ll want to drink more to stay hydrated. Just listen to your body – it usually tells you when you’re thirsty and what you need.”
Myth 2: Tea and coffee count towards your recommended daily fluid intake
Yes, the NHS2 says that tea and coffee count towards your quota, but Leila suggests being mindful of caffeine. Because it’s a mild diuretic, it could increase wee production.
“I recommend having a glass of water with your cup of coffee. In Italy, you’re always offered a glass of water with your espresso for that reason.” On hotter days, adding extra ice to your iced coffee might have a similar benefit.
Myth 3: If your pee is dark-yellow, you’re not drinking enough
Yes, the colour of your pee is a great indicator of whether you’re dehydrated or not. “If you’re properly hydrated, your wee should be a pale yellow,” says Leila. Dark orange or amber means you might need to level up on the H2O.
However, taking supplements containing B vitamins can also turn your wee a brighter or darker shade of yellow. Dark yellow pee might also indicate an underlying issue. “If you’re drinking enough water or not taking any supplements or medications, get it checked out with your GP,” advises Leila.
Myth 4: Too much water causes bloating
This only happens if you drink large amounts of water in one go. When the body can’t get rid of excess water, cells swell to accommodate it. As a result, you might feel puffy or bloated until you slow your water intake and your kidneys catch up.
And while the water itself shouldn’t cause bloating, the way you drink it might. Drinking and eating too fast at the same time, or drinking through a straw or from a bottle, can cause you to swallow more air than normal, according to Leila. “Try to focus on sipping water with your meal.”
Some believe drinking less helps you avoid water retention. Again, the science here is often misunderstood. “People think that to avoid this, they should drink less water, but it really depends on the cause,” says Leila.
Common causes of water retention include circulatory, kidney, lymphatic, and hormonal issues, and it can also happen when you’re pregnant. “Restricting water won’t usually help and staying hydrated is more important.” Speak to your doctor if you are experiencing any symptoms related to the above to rule out anything serious.
“If you’re working out regularly, you could also top up with electrolyte drinks”
Myth 5: Only water counts towards your fluid intake
Water is a healthy and cheap choice to keep you hydrated, but other drinks can also count towards your fluid intake. We also get some fluids from the foods we eat.
While water does a very good job of quickly hydrating your body, one study3 found that milk might be more hydrating. Researchers think drinks with a little sugar, fat or protein could help keep you hydrated for longer. “It also contains calcium and electrolyte minerals sodium and potassium,” says Leila. These carry an electric charge through the blood and body fluids, keeping hydration at a healthy level.
“If you’re working out regularly, you could also top up with electrolyte drinks. Coconut water is also very high in natural electrolytes.”
Myth 6: Drinking water before bed staves off a hangover
If you’ve had a heavy night, no amount of water will prevent the hangover the next day. “This is mainly thanks to a toxin in alcohol called acetaldehyde,” says Leila. “The effects of acetaldehyde produced during alcohol metabolism can persist well into your hangover and might be responsible for the nausea and vomiting some unlucky people experience.”
Leila’s advice is to keep hydrated while drinking alcohol. Try having a glass of water between every couple of drinks, and this might reduce the severity of your hangover – helping to reduce things like headaches caused by pure dehydration. “Rehydration tablets can also help to replace all the lost salts and sugars due to the extra alcohol,” says Leila. But again, it won’t curb the hangover completely.
Myth 7: There's no such thing as drinking too much water
“It’s rare, but it can happen,” says Leila. Glugging too much water can cause overhydration, leading to water toxicity.4 When your body’s water level becomes too high for your kidneys to excrete, the electrolytes in your body become diluted – fluid can then move inside your cells and cause inflammation. The kidneys can process about 800ml - one litre of fluid an hour,5 so more than that over a number of hours could be risky.
Thankfully, new research shows that – when working efficiently – our brains prevent us from drinking too much. “One study6 found that people swallowed water a lot easier after exercise when dehydrated, compared to when they’d already drank an excess amount of water,” says Leila. Experts think that the brain activates a ‘swallowing inhibition’ after you’ve drunk excess liquid, helping to balance levels of water in the body.
Stress, busy days and distractions can cause you to forget to drink, so reminder apps and water bottles can help. Ironically, if you’re stuck in meetings all day – “The more you talk, the more you need water,” says Leila. Pausing and listening to your body’s signals can help. “Once you start thinking about how thirsty you are, it’s difficult to ignore – it’s happening to me right now!” laughs Leila.
“You don’t have to drink every hour if you don’t feel like it, but try not to wait to drink until you’re really thirsty as chances are you’re already dehydrated.”
Myth 8: You don’t need to drink more when you travel
The opposite is true, especially if you’re flying, as you can dehydrate more easily. “Because of the lower oxygen pressure and the lower humidity, dehydration can happen quicker,” says Leila. “We lose water as you exhale more and as you talk, but the low humidity also causes a higher level of water loss throughout the body.” 7,8
Leila recommends drinking regular sips of water for every hour of your flight. “You could also use electrolyte sachets on the plane,” she suggests. “This will keep you topped up with essential minerals.” And go easy on the alcohol as this is very dehydrating.
The final say
Healthy hydration is a bit more complex than most people think. But Leila’s overall advice is to listen to your body and keep things simple.
If in doubt, we have experts on hand who can provide trusted, in-depth advice on which hydrating products are worth it and help you make the healthiest decisions.
The advice in this article is for information only and some of the information reflects the opinion of our in-house nutritionist and should not replace medical care. Please check with your GP or healthcare professional before trying any supplements, treatments or remedies. Food supplements must not be used as a substitute for a varied and balanced diet and a healthy lifestyle.
1. NHS. The Eatwell Guide [Internet]. NHS. 2022. Available from: https://www.nhs.uk/live-well/eat-well/food-guidelines-and-food-labels/the-eatwell-guide/
2. National Health Service. Water, Drinks and Your Health [Internet]. nhs.uk. 2023. Available from: https://www.nhs.uk/live-well/eat-well/food-guidelines-and-food-labels/water-drinks-nutrition/
3. Rj M, P W, Pa C, Np W, Sj O, A D, et al. A Randomized Trial to Assess the Potential of Different Beverages to Affect Hydration Status: Development of a Beverage Hydration Index [Internet]. The American journal of clinical nutrition. 2016. Available from: https://pubmed.ncbi.nlm.nih.gov/26702122/
4. Peechakara BV, Gupta M. Water Toxicity [Internet]. Nih.gov. StatPearls Publishing; 2019. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537231/
5. Can You Drink Too Much Water? [Internet]. www.uhhospitals.org. 2024. Available from: https://www.uhhospitals.org/blog/articles/2024/01/can-you-drink-too-much-water
6. Monash University. Study Challenges Idea of Mandatory Water Intake | Newswise [Internet]. Newswise.com. Newswise; 2016 [cited 2024 Nov 18]. Available from: https://d.newswise.com/articles/study-challenges-idea-of-mandatory-water-intake
7. Zieliński J, Przybylski J. [How much water is lost during breathing?]. Pneumonologia I Alergologia Polska [Internet]. 2012;80(4):339–42. Available from: https://pubmed.ncbi.nlm.nih.gov/22714078/
8. Skin Water Loss - an overview | ScienceDirect Topics [Internet]. www.sciencedirect.com. Available from: https://www.sciencedirect.com/topics/medicine-and-dentistry/skin-water-loss
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