ThirstyBotYou become dehydrated when you lose more water (sweat, urine, diarrhoea, vomiting) than you drink. Most cases are mild and clear up once you drink enough. What matters is spotting it early and knowing when not to manage it at home.
Mild dehydration
- Thirst and a dry mouth.
- Tiredness, poor focus, a mild headache.
- Light-headedness when you stand up, a fast heartbeat.
- Muscle cramps.
- Peeing less, with dark yellow urine. On the 8-colour urine chart, levels 1–3 (almost clear to straw yellow) mean you are hydrated, and level 4 and above mean drink more.
What to do: rest somewhere cool and sip steadily over the next few hours rather than downing a large amount at once. Healthy kidneys clear only about 0.8–1 litre of water an hour, so drinking faster than that does not help and can dilute your blood sodium.
Serious signs: get medical help now
Seek care or call your local emergency number if you notice any of these:
- Lethargy, confusion or unconsciousness.
- Sunken eyes, or being unable to drink.
- A skin pinch on the belly that takes 2 seconds or more to flatten.
- A severe headache, repeated vomiting, seizures, fainting or worsening breathlessness.
Young children, older adults and people with heart or kidney disease dehydrate faster and notice it later. Do not wait for serious signs in these groups.
After diarrhoea or vomiting
Plain water does not replace the salts you have lost. WHO recommends oral rehydration solution (ORS) mixed exactly as the packet says. If you take diuretics or are on a low-salt diet, ask a doctor before using a lot of ORS.
Preventing dehydration on hot days
- Drink on a schedule instead of waiting for thirst. For outdoor work in the heat, NIOSH advises about 1 cup every 15–20 minutes.
- Drink more on hot days and workout days.
- Check your urine colour through the day. Pale straw yellow is the target.
To find your own daily goal, try the water intake calculator. It uses the same formula as the ThirstyBot app, based on your weight, age and activity.
ThirstyBot does not replace medical advice. If you have a medical condition, ask your doctor how much water is right for you.
