Dehydration by severity.
- • Thirst — your body's first signal (often already too late)
- • Dry mouth and slightly sticky saliva
- • Dark yellow urine — should be pale straw yellow
- • Reduced urine frequency (less than 4× per day)
- • Mild headache
- • Slight fatigue
Moderate (3–5% fluid loss)
- • Strong, persistent headache
- • Significant fatigue and reduced exercise performance
- • Difficulty concentrating and brain fog
- • Rapid heartbeat (tachycardia)
- • Reduced sweating in hot conditions
- • Muscle cramps
- • Nausea
Severe (>5% fluid loss) — Seek medical help
- • Extreme thirst
- • Very dark or no urine output
- • Sunken eyes
- • Rapid, weak pulse
- • Confusion or delirium
- • Loss of skin elasticity (poor skin turgor)
- • Fainting or loss of consciousness
How to rehydrate quickly.
1. Drink water immediately
Start with 500ml of cool (not ice cold) water. Cold water is absorbed faster than warm water.
2. Add electrolytes for moderate dehydration
For fluid loss from exercise or heat, add electrolytes (sodium, potassium) via sports drink or electrolyte tablets.
3. Eat water-rich foods
Cucumber (96% water), watermelon (92%), strawberries (91%), and celery (95%) accelerate rehydration alongside drinking.
4. Avoid diuretics temporarily
Limit coffee, alcohol, and energy drinks until rehydrated. These compounds increase urine output and worsen dehydration.
5. Rest in a cool environment
Reduce sweat rate by moving out of heat. Cooling your body reduces further fluid loss while you rehydrate.
⚕️ Medical note: This page describes general signs of dehydration for educational purposes only. If you or someone else experiences severe symptoms such as confusion, rapid heartbeat, or loss of consciousness, seek emergency medical care immediately. This content is not a substitute for professional medical advice.
Prevention is better than cure.
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