Hydration and Wellness: How Much Water Do You Actually Need?
Beyond the old '8 glasses' rule — practical guidance on how much to drink, electrolytes, and how to make water more interesting.
Hydration touches everything — mood, focus, blood pressure, digestion, even your skin. But the famous '8 glasses a day' rule has no real scientific basis; what you actually need depends on your body size, activity, climate and diet.
A reasonable target
For most adults, about 30–35 mL per kg of body weight per day, including what you get from food. A 70 kg adult lands at around 2.5 L in total.
Eat your water
Cucumber, watermelon, citrus, soup and yogurt are all 80–95% water — and they bring electrolytes along with them.
Add a little salt
A pinch of sea salt and a squeeze of lemon in your first glass of the morning supports the adrenal response and electrolyte balance.
Coffee and tea count
Their diuretic effect is modest, so caffeinated drinks still count toward your daily hydration.
Signs you're under-hydrated
Headache, low energy, dry lips, dark yellow urine, dizziness on standing.
Frequently asked questions
+Can I drink too much water?
Yes — it's rare but possible (hyponatremia). Match your intake to your thirst, climate and activity, and don't force liters.
Sources & references
Background reading
- The Nutrition Source — Harvard T.H. Chan School of Public Health