The useful points to carry forward
- Review the forecast and official heat alerts.
- Plan water, shade, rest and transport before going out.
- Never leave a person or animal in a parked vehicle.
- Ask a clinician whether illness or medicines change heat risk.
Heat affects more than comfort
During unusually hot days and nights, the body works harder to keep its internal temperature stable. Heat can worsen cardiovascular, respiratory, kidney, metabolic and mental-health conditions. It may also increase fatigue, reduce concentration and raise the chance of accidents at work, during travel or while exercising.
Risk depends on temperature, humidity, duration, activity, housing and access to cooling. Older adults, infants, pregnant people, outdoor workers, people living alone and those with some chronic conditions or medicines may be more vulnerable. A person can be at risk even if they do not feel extremely thirsty.
Reduce exposure before symptoms begin
Official weather and heat alerts can guide plans. When possible, strenuous tasks can be moved away from the hottest part of the day, and time can be spent in shade or a cooler place. Light, loose clothing and regular access to water also support the body's cooling processes.
Homes may stay cooler when direct sun is blocked during the day and cooler night air is used when conditions allow. Fans are not enough in every temperature or for every person, so local public-health guidance matters. Checking on someone who is older, unwell or living alone can reveal problems early.
- Review the forecast and official heat alerts.
- Plan water, shade, rest and transport before going out.
- Never leave a person or animal in a parked vehicle.
- Ask a clinician whether illness or medicines change heat risk.
Know when heat becomes urgent
Heavy sweating, weakness, headache, dizziness, nausea or cramps can signal heat illness. Confusion, collapse, seizures or very hot skin can indicate a medical emergency. Rapid cooling and urgent professional assessment are important; follow the emergency-care guidance where you are.
This article is general education, not a diagnosis or a personal fluid plan. Some people with heart or kidney conditions have prescribed fluid limits, so generic hydration targets may be unsafe for them. A healthcare professional can provide advice based on health conditions and medicines.
Guidance can change. This source was last checked for this article on 24 April 2026. See the editorial policy.