Are You Hydrating… or Just Peeing? The Big Mistake of Water Without Electrolytes

1. Summer, sunshine… and the dehydration you didn’t see coming

Meet Clara. 36 years old, mother of two, weekend runner and green smoothie lover. This summer, she spent a few days on the Costa Brava. Gorgeous sun, coffee for breakfast, beach walks… and a glass of white wine on the terrace. All good until one morning, she went out for a run and stopped after 10 minutes: dizzy, heart racing, legs like jelly.

“I don’t get it. I’ve been drinking water all day,” she said. What Clara didn’t know is that water alone wasn’t enough. She was missing electrolytes. Our bodies are 60% water... but we also need sodium, potassium, magnesium and other minerals to function properly. That’s the key.

2. Dehydration or “volume depletion”? Not the same

Many people confuse the two, but they’re different (though they can overlap).

• Dehydration: water loss without losing electrolytes. Think: sweating out just water without sodium.
• Volume depletion: water + electrolyte loss (mostly sodium). This throws your entire system off balance.

Your body regulates water based on blood salt concentration (osmolarity). If you lose only water → concentration increases. If you lose both water and salts → everything goes out of sync.

3. How do we lose water (and electrolytes)?

• Urine: a natural process, but increased by caffeine or alcohol.
• Sweat: the main route during exercise or heat.
• Breathing: yes, we also lose water when we breathe—especially in airplanes or dry environments.

Factors that accelerate fluid loss:

• Flights (cabin air is extremely dry)
• Caffeine (makes you pee more)
• Alcohol (blocks vasopressin, increases water loss)
• Fasting (no food = no sodium intake)
• Extreme heat + poor clothing choices

4. How to fix it? ELECTROLYTES (not just water)

The most common mistake: thinking more water will fix it. ❌ Wrong.

You need to replace what you lose: water + sodium (and a bit of potassium and magnesium). Sodium is the most important. Magnesium is best taken separately as a supplement, and too much potassium can be dangerous.

Proper electrolytes help you:

• Rehydrate efficiently
• Prevent cramps, fatigue, and dizziness
• Improve fluid absorption
• Maintain cellular balance

When should you take electrolytes?

• When exercising > 1 hour
• When sweating a lot
• When fasting
• When traveling or exposed to extreme heat

Avoid sugar-loaded drinks like Gatorade. Opt for hypotonic or isotonic solutions with real sodium and minimal sugar.

5. The exercise case: what happens if you don’t replenish properly

If you exercise regularly, this matters even more. Real example: endurance cyclists. Losing just 2% of body weight in water causes:

• ???? +1ºC increase in body temperature
• ❤️ +15 beats per minute
• ???? +15% perceived exertion
• ⏳ +15% more time to complete the race
• ⚡ -10% drop in power output

Sound familiar—feeling exhausted too soon? It may not have been poor fitness… but silent sodium-free dehydration.

Even worse: taking gels or sugary drinks without enough water = poor absorption → more fatigue, worse performance.

6. Conclusion: This summer, hydrate wisely (with electrolytes)

Your body doesn’t just need water. It needs balance. And that balance comes from sodium.

Drinking only water when you sweat or fast can backfire. The solution? Add electrolytes to your routine, especially if you exercise, travel, or face heat stress.

See you at the beach… with your bottle fully loaded.