The 'Eight Glasses a Day' rule is finally being rewritten

The hydration breaks at this summer's World Cup sparked plenty of debate online, but they also highlighted a much bigger shift happening in health… 

The internet had plenty to say about this summer's World Cup. As soaring temperatures swept across the host cities in the US, mandatory hydration breaks became a regular feature of matches. Social media quickly filled with jokes about football becoming "too soft" or players needing a water break every few minutes. But beneath the swathes of memes was a serious reminder: hydration shouldn’t be a luxury.

In football, it can be framed as a performance strategy, and a personalised one at that. For years, many of us have grown up believing the same rule… drink eight glasses of water a day. It's as simple as that, right?

Well, as it turns out, not particularly scientific. In reality, there has never been a universal amount of water that works for everybody. Your hydration needs depend on everything from your age, body size, and activity levels to the temperature, humidity, and even what you've eaten that day. But don’t fret, it isnt as intimidating as it sounds.

Experts are beginning to move away from blanket advice and towards personalised hydration strategies for the masses, making it easier for us all to track how we hydrate on a daily basis. The European Food Safety Authority recommends an adequate daily water intake of around 2 litres for women and 2.5 litres for men, but stresses that this includes water from both drinks and food. On top of that, anyone exercising, working outdoors, or spending prolonged periods in the heat will need significantly more fluid to replace what is lost through sweat.

And that's where electrolytes come into the conversation. As temperatures rise in the UK, it is vital to know how we replace the water lost through sweat. When we sweat, we don't just lose water, but also essential minerals including sodium, potassium, and magnesium. These minerals help regulate fluid balance, nerve signalling, and normal muscle function in our bodies. Replacing water without replacing electrolytes after prolonged sweating can make it harder for the body to retain fluid effectively, particularly during endurance exercise or periods of extreme heat.

Research from the American College of Sports Medicine suggests that losing as little as 2% of body weight through dehydration can impair endurance, concentration, and physical performance. Studies have also shown dehydration can affect reaction time, mood and decision-making, which are factors that matter just as much in an office 9 to 5 as they do on a football pitch or in the gym.

Whether it's Wimbledon players carefully replacing fluids between changeovers or footballers using cooling and hydration breaks during extreme temperatures, recovery for athletes begins months in advance. Sports scientists now tailor hydration plans based on sweat rate, sodium losses, and environmental conditions rather than relying on generic recommendations like the ‘eight glasses a day’ advice.

The rest of us may not have access to a team of performance nutritionists (we wish), but the principles remain the same. If you're exercising in hot weather, heading out for a long run, spending time dancing at a festival, or simply commuting on the bus during a heatwave, your body is working harder to stay cool. Waiting until you feel thirsty may not always be the best indicator either, as thirst often lags behind the body's actual fluid needs during prolonged activity.

Instead of obsessing over hitting an arbitrary water target, experts recommend paying attention to your own routine. Consider how much you're sweating, the weather, the intensity of your activity, and how you feel before, during, and afterwards. Pale straw-coloured urine, stable energy levels, and recovering well after exercise are all useful indicators that your hydration strategy is working.

Think of hydration in the same way you think about clothing. You wouldn't wear the same outfit in January as you would during a July heatwave, so why expect your hydration needs to stay the same? The amount you drink (and whether you need electrolytes) should adapt to your environment, your activity levels, and your body's demands.

So we can discuss hydration breaks until we are blue in the face and call the England team “soft”, but they are vital for our bodies. Far from being a sign of weakness, they're evidence that sports science is finally evolving and that performance is no longer about ultimate endurance. Hydration isn't simply about drinking more water, but about understanding what your body needs, when it needs it, and recognising that one-size-fits-all advice in wellness and sport no longer reflects what the science tells us.