Dehydration is a loss of water and ions. Heatstroke is an emergency: the body cannot regulate its temperature. Confusing the two costs time. This article first separates the signs, then covers recovery after exertion in the heat.
Hydration for training (when to use an isotonic drink): training without electrolytes. An everyday overview of ions: electrolytes.
Signs — from thirst to emergency
- Mild dehydration — thirst, dark urine, fatigue, headache.
- Heat exhaustion — heavy sweating, weakness, nausea, dizziness, cold clammy skin; consciousness preserved.
- Heatstroke — confusion, fainting, hot dry or paradoxically moist skin, sweating stops, seizures. Emergency help. Cool them down while you wait.
Don’t give a drink to a person who is not conscious. Don’t put them in an ice bath without supervision if they are confused — cool the armpits, neck and groin, move them into the shade, remove extra clothing.
Prevention in the heat
- Exertion in the morning or early evening, not at 14h.
- Light-colored clothing, a hat, breaks in the shade.
- Water according to thirst + salt in your meal; not liters of distilled water on an empty stomach.
- Alcohol and a heavy lunch before outdoor work — a bad combination.
- Medicines (diuretics, some psychiatric ones) — ask your doctor about the heat.
Recovery after exertion — when it’s not urgent
- Shade, lukewarm water on the skin, legs slightly raised if you feel dizzy.
- Fluids in small sips. If the session was long and salty, ions — ISO Max is one option, used according to the label.
- A meal with potassium and protein within the next hour (potatoes, yogurt, banana, meat).
- Don’t jump straight into a second workout “to sweat more.”
Magnesium as a daily base, not as first aid: magnesium citrate. Sports: fitness and active living.
Children, older adults, the chronically ill
Less thirst, faster decompensation. Don’t wait for them to ask for water. Diabetes, heart, kidneys — the threshold for seeing a doctor is lower.
After a hot workday, write down how much you drank, whether there was salt in your meal and what your urine looked like. That’s better than buying a third powder. If you work outdoors, arrange shade and breaks with your coworkers before it becomes urgent — prevention is a team effort, not a heroic one.
Frequently asked questions
- How do I know it’s not just fatigue?
- Confusion, sweating stops, collapse — this is not fatigue. Call for help.
- Should I drink only water after a half marathon?
- After long exertion, water plus ions and a meal. Plain water by the liter risks hyponatremia.
- Does coffee help with heatstroke?
- No. Caffeine is not a therapy. Cooling and emergency help.
- Can I go back to work the same day?
- After mild dehydration — yes, slowly. After exhaustion — rest. After heatstroke — only once a doctor has seen you.
- Does an isotonic drink treat heatstroke?
- No. Supplements are not emergency medicine.
This article is for informational purposes and does not replace emergency medical care. If you suspect heatstroke, see a doctor immediately. Food supplements are not medicines. Results vary from person to person.
