Extreme heat is one of the most underestimated weather hazards. A heatwave can push the body past its ability to cool itself, leading to heat exhaustion or the medical emergency of heatstroke. The risks rise quickly and quietly, so knowing the warning signs and a few simple precautions can be genuinely protective during a hot spell.
Who is most at risk
- Older adults, especially those living alone or with limited mobility.
- Babies and young children, who heat up faster than adults.
- People with heart, lung, kidney, or mental health conditions, or diabetes.
- Anyone taking certain medicines that affect hydration or temperature regulation.
- People who work or exercise outdoors, and those without access to cooling.
Practical ways to stay cool
- Drink water regularly throughout the day, before you feel thirsty, and limit alcohol and very sugary drinks.
- Stay out of the sun during the hottest hours, often late morning to mid afternoon.
- Keep your home cool: close curtains on sun-facing windows by day, open up when it's cooler at night.
- Wear loose, light, breathable clothing and use cool showers, damp cloths, or fans wisely.
- Never leave children, vulnerable adults, or pets in a parked vehicle, even briefly.
Check on others
Many heat-related illnesses happen to people who are alone. Check on older neighbors, relatives, and anyone with health conditions at least once a day during a heatwave.
Spotting heat exhaustion
Heat exhaustion is the warning stage. Signs include heavy sweating, tiredness, dizziness, headache, nausea, muscle cramps, fast breathing or heartbeat, and intense thirst. If you act early, it is usually reversible. Move the person to a cool place, help them lie down with legs slightly raised, give sips of water or an oral rehydration drink, and cool the skin with water and fans. They should start to feel better within about 30 minutes.
Heatstroke is a medical emergency
If someone is confused, agitated, not making sense, has stopped sweating despite the heat, has very hot skin, a rapid or weak pulse, seizures, or loses consciousness, treat it as heatstroke. Call 911 (US/CA), 999 (UK), or 112 (EU) immediately. While waiting, move them somewhere cool and cool them aggressively with water and fanning. Do not give fluids to someone who is not fully alert.
Heat, medicines, and chronic conditions
Some medicines need to be stored below a certain temperature and may be affected by extreme heat, and a few can change how your body handles heat and fluids. Do not stop any prescribed medicine on your own. Ask a pharmacist or doctor how to store your medicines safely in hot weather and whether any of them increase your heat risk.
When to seek advice
If you have a chronic condition, care for someone vulnerable, or feel unwell during a heatwave but aren't sure how serious it is, get advice rather than waiting. A verified doctor on iHealix can help you assess symptoms, review how your medicines and conditions interact with extreme heat, and tell you whether you need urgent in-person care. This article is for general information and does not replace personalized medical advice.