When temperatures rise, the body works harder to maintain a normal temperature. Sweating helps cool the body, but the loss of water and salts can lead to fatigue, dizziness, cramps, dehydration, and heat-related illnesses.
The risk increases when you spend long periods in the sun, do physical work, exercise in the heat, do not drink enough fluids, or spend too much time in a hot and poorly ventilated environment. Even days that do not seem exceptionally hot can be dangerous for more vulnerable people.
Drink fluids regularly
Do not wait until you are very thirsty. Drink water throughout the day, especially when you sweat, work outdoors, or do physical activity.
Avoid the hottest hours
Limit going outside and strenuous activity during the hottest part of the day. When you need to go out, seek shade and take frequent breaks.
Stay in cool places
Use shade, ventilation, or cooler indoor spaces. Close curtains when direct sunlight enters and ventilate the home when the air outside is cooler.
Dress lightly
Choose loose, lightweight clothing that allows airflow. Outdoors, wear a wide-brimmed hat and protect your skin from direct exposure.
Do not wait for the body to show strong warning signs
Thirst, fatigue, headache, and dizziness can be early signs that the heat is affecting the body. Stop the activity, move to a cool place, and drink fluids before the condition gets worse.
Do a simple check
A little preparation can make the day safer. Check the conditions, adjust your activity, and take with you the things that help you stay cool.
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Check the weather forecast and heat warnings
Check the temperature, humidity, and local heat alerts before work, travel, or physical activity.
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Take water with you
Do not rely only on the possibility of finding water somewhere along the way. Keep a bottle nearby and drink at regular intervals.
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Plan for shade and rest
Decide in advance where you can rest, cool down, or enter a cooler environment.
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Tell someone when you are working alone
When working or exercising alone in the heat, inform another person and keep a way to communicate.
Heat does not affect everyone in the same way
Some people have more difficulty regulating their body temperature, recognizing thirst, or moving away on their own from a hot environment. They should be checked on and helped more often during hot days.
Children depend on adults for water, clothing, and cooling. Never leave them alone in a parked vehicle, even when the windows are open or the stop seems brief.
Check on them regularly, especially when they do not have air conditioning, have limited mobility, or find it difficult to access water and a cool environment.
Heart, lung, and kidney problems, diabetes, and some mental health conditions can worsen in the heat. Some medications can affect sweating, hydration, or the body's response to heat.
Workers, athletes, and people doing strenuous activity should increase their workload gradually, take frequent breaks, and have continuous access to water and shade.
What can heat exhaustion look like?
Heat exhaustion can develop gradually. The person may still be conscious and sweating heavily, but needs to stop the activity and cool down immediately.
Heavy sweating
Clothes may become soaked quickly and the person may be very thirsty or have a dry mouth.
Dizziness and weakness
The person may feel unsteady, very tired, weak, or close to fainting.
Headache and nausea
Headache, loss of appetite, nausea, or vomiting may occur.
Rapid pulse
The heart may beat faster and breathing may become quicker than usual.
Muscle cramps
Pain or tightening may occur in the legs, arms, or abdomen, especially after heavy sweating.
Cool, clammy, and pale skin
The skin may feel cool or damp even though the environment is very hot.
What should you do when someone feels unwell from the heat?
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Move them to a cool place
Move them away from the sun or hot environment and help them sit or lie down.
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Remove unnecessary clothing
Loosen tight clothing and remove jackets, shoes, or layers that prevent cooling.
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Cool the skin
Use cool water, wet towels, a fan, or cool air. You can place cool compresses on the neck and under the armpits.
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Give fluids when the person is conscious
Give cool water in small sips. A rehydration solution or isotonic drink may also be used when there has been heavy sweating.
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Stay nearby and monitor their condition
Do not leave them alone. If they do not improve quickly, their condition worsens, or signs of heatstroke appear, seek medical help immediately.
Know the signs of heatstroke
Heatstroke is the most severe form of heat-related illness. The body can no longer control its temperature, and organs can be damaged quickly.
Confusion, disorientation, unusual behavior, difficulty speaking, loss of coordination, seizures, or loss of consciousness are warning signs.
The person's body may be very hot, with rapid breathing and a strong or fast pulse. The skin may be hot and dry, but sweating may also occur.
Heatstroke requires emergency medical help. Call emergency services and begin cooling the person while waiting for help. Do not give anything to drink to a person who is unconscious, very confused, or unable to swallow safely.
Reduce indoor heat
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Block direct sunlight
Close curtains, blinds, or shutters on windows exposed to sunlight, especially during the hottest part of the day.
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Ventilate at the right time
Open windows when the air outside is cooler, usually in the evening, during the night, or early in the morning.
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Reduce sources of heat
Limit the use of the oven, stove, and appliances that produce a lot of heat during the hottest hours.
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Spend time in a cooler place
When the home remains very hot, spend a few hours in a cool or air-conditioned environment when possible.
Seek medical help immediately if the person is confused, does not respond normally, loses consciousness, has a seizure, difficulty breathing, a very high temperature, very hot skin, or does not improve after cooling. Heatstroke is an emergency and should not be expected to pass on its own.
References
- Centers for Disease Control and Prevention. (2026, March 3). Heat-related illnesses.
- Centers for Disease Control and Prevention. (n.d.). Heat illnesses. Travelers’ Health.
- National Health Service. (n.d.). Heat exhaustion and heatstroke.
- National Health Service. (2026, June 12). Heatwave: How to cope in hot weather.
- World Health Organization. (2026). Heat and health.
- World Health Organization Regional Office for Europe. (2026, June 8). #KeepCool in the heat.
