Dehydration alone is rarely life-threatening, but it becomes relevant in combination with hyperthermia and stimulants. In clubs, the rule of thumb is roughly 250–500 ml of water per hour of dancing, ideally with an electrolyte component (broth, lightly salted water, isotonic drinks).
The transition to hyponatremia (too much water, too little sodium) is a real risk of confusion — especially with MDMA, which has an antidiuretic effect and blocks water excretion. Signs of hyponatremia rather than dehydration:
- Headache, nausea, vomiting
- Confusion
- Watery appearance, bloating
- Seizures (late sign)
If unclear: no more water without salt or electrolytes, sit the person down, observe, and when in doubt call 112.