How Much Water Should You Really Drink?

We've all heard the advice, "Drink eight glasses of water every day!" But is this one-size-fits-all rule supported by science? Is hydration more complex than we've been led to believe?

With so much contradicting information—from influencers promoting excessive water consumption to misunderstandings about dehydration—it's time to distinguish reality from fiction. How much water do you actually need? Let's get into the science of hydration.

The myth of the "8x8 rule"

The idea that everyone requires exactly eight 8-ounce glasses (about 2 litres) of water per day is not supported by strong scientific evidence.This recommendation is most likely based on a 1945 Food and Nutrition Board report, which suggested a daily water intake of about 2.5 liters—but it was important to note that the majority of this comes from food and beverages, not just plain water.

What Does Science Say?

Your hydration needs depend on a number of things, 

including:

• Body size and composition (larger people need more water)

• Activity level (exercise increases fluid loss)

• Climate (hot or dry weather increases sweat loss)

• Diet (water-rich foods like fruits and soups contribute to intake)

• Health conditions (pregnancy, illness, or kidney function affect needs)

The National Academies of Science, Engineering, and Medicine recommends:

• Men: around 3.7 litres (125 oz) of total water per day (including all beverages and food).

• Women: about 2.7 litres (91 oz) of total water per day.

But here's the thing: just approximately 80% of this needs to come from drinks; the rest comes from meals.

Do You Really Have to "Chug Water All Day"?

Contrary to popular opinion, you do not have to force yourself to drink water continually. Your body excels at controlling hydration through:

• Thirst (a reliable signal for most healthy people)

• Urine color (pale yellow = well-hydrated; dark yellow = drink more)

• Kidney function (they adjust water retention based on needs)

Can you drink too much water?

Yes! Overhydration (hyponatraemia) happens when too much water dilutes sodium levels in the blood, causing severe swelling in the brain. This is uncommon but can occur under extreme circumstances (for example, marathon runners drinking too much without electrolytes).

Hydration Beyond Water: Other Fluid Sources

You do not need to rely exclusively on simple water. Many foods and drinks promote hydration:

• Fruits and vegetables (watermelon, cucumber, oranges: 90%+ water)

• Milk, herbal tea, and broths (all hydrate well)

• Coffee and tea (moderate caffeine does not dehydrate you).

Practical Hydration Tips

1. Listen to your body – Drink when thirsty.
2. Check urine color – Aim for light yellow.
3. Adjust for activity – Drink extra before, during, and after exercise.
4. Eat water-rich foods – About 20% of intake comes from food.
5. Don’t overdo it – No need to guzzle water if you’re not thirsty.

Final Verdict: How Much Water Should You Drink?

There is no universal number. Instead than stressing about a specific amount, utilise these scientifically supported guidelines:

• Most people stay hydrated by drinking when they're thirsty and eating a well-balanced diet.

• Active people or those in hot climates may require more.

• Thirst signals weaken with age, so older adults may need reminders to drink.

Forget the myths—your body is smarter than you think. Stay hydrated, but don’t stress over hitting an arbitrary number. Cheers to that! 🚰💧