Climate change is bringing more frequent periods of hot weather that are expected to become longer and more intense. This has important implications for the health and well-being of the population. Prolonged periods of heat are expected to place a substantially greater strain on the human body. The extent of these effects depends on a number of factors, including age, underlying health conditions, general physical fitness, and the duration and nature of heat exposure. As these changes are relatively new, there is limited evidence and practical experience regarding their full impact. Therefore, preparing for periods of hot weather is more important than ever.
During periods of hot weather, everyone should plan their daily activities in a way that allows them to follow as many hot weather guidance as possible. Particular attention should be paid to keeping homes and workplaces as cool as possible. Prevent warm air from entering indoor spaces by keeping windows closed during the hottest part of the day and shading them with external sun-blocking devices such as shutters or blinds.
It is also advisable to implement heat-protection measures at the community level. In addition to providing green spaces with adequate shade, it is important to ensure access to publicly available air-conditioned facilities, such as libraries, sports centres, schools, or other suitable buildings, wherever these are available. This is especially important in areas affected by the urban heat island effect and for communities with a high proportion of vulnerable residents.
Who is most affected by hot weather?
Hot weather can affect everyone. However, some population groups are particularly vulnerable:
- Older adults, infants and young children, and pregnant women.
- People with underlying health conditions. Those at greater risk include individuals with medical conditions that affect the body’s ability to regulate temperature, mobility, or judgement. These include people with cardiovascular or respiratory diseases, diabetes, kidney disease, disabilities or reduced mobility, as well as those experiencing diarrhoea, vomiting, or fever. The use of certain medications may also impair the body’s ability to regulate heat.
- People exposed to environmental risk factors. This includes individuals exposed to air pollution or living in poor housing conditions, such as top-floor or attic apartments, poorly ventilated or overcrowded dwellings, or homes without air conditioning.
- Outdoor workers. People working outdoors or in workplaces that become hot because of industrial processes or building characteristics are at increased risk. Recreational athletes and travellers may also be more vulnerable.
- People experiencing socioeconomic disadvantage. People with low incomes, homeless people, socially isolated people, and refugees may have more limited access to cool environments and healthcare services.
- Urban residents. Heatwaves are often more intense in cities because vegetation has been replaced by asphalt and concrete, which absorb and retain heat while reducing surface moisture. The complex geometry of streets and buildings also alters airflow, and additional heat generated by human activities further increases temperatures. Together, these factors create the urban heat island effect, whereby urban areas absorb heat during the day and release it slowly at night. As a result, night-time temperatures remain higher, limiting the body’s ability to recover from daytime heat exposure. This effect may become even more pronounced during prolonged heatwaves.
How can hot weather affect your health?
Prolonged periods of hot weather can lead to a range of health problems and may cause the body to overheat, including:
- Discomfort and reduced well-being that do not yet pose a serious health risk.
- Worsening of existing medical conditions.
- Heat rash.
- Heat cramps.
- Heat exhaustion.
- Fainting (syncope) – a brief loss of consciousness.
- Heat stroke.
How can we prevent health-related health problems?
The body can overheat both outdoors and in excessively hot indoor environments. Heat-related problems can be prevented by reducing heat exposure and helping the body cool down in various ways described below.
Reduce heat exposure:
- Cool your home and yourself.
- Move to shaded areas or cooler places. Keep indoor spaces cool by ventilating them at night, early in the morning, and in the evening, and limiting ventilation during the hottest part of the day. Use external shading devices that reflect sunlight and significantly reduce indoor heat gain. Switch off electrical appliances that are not needed, as they generate heat even when in standby mode and can further warm up indoor spaces.
- If these measures are not sufficient, use fans and air conditioning. However, be aware that these devices consume energy and may generate additional heat. Fans can help cool the body when air temperatures are up to 35 ° Air conditioning systems are effective for cooling indoor spaces. Whenever possible, spend time in cool, air-conditioned environments. If your home or workplace is too hot, seek out publicly accessible cool spaces. Spending even a few hours a day in a cooled environment can help reduce the strain that heat places on the body. If possible, leave urban areas and spend time in nature, in the shade of trees. You can also cool down by taking a cool shower or bath or by applying cool damp cloths to the head, neck, hands, or feet.
Reduce heat production in the body:
- Limit physical activity, as the body generates heat during exercise and other physical exertion. Outdoor physical activity should be limited to the morning and evening hours.
- Eat light meals and choose smaller portions.
Help the body release the heat:
- Choose appropriate clothing. Wear lightweight, loose-fitting clothes.
- Drink enough fluids. This helps replace the fluids lost through sweating in hot conditions. Sweating is essential for cooling the body during exposure to high environmental temperatures and during physical activity (work, sports, play, etc.). Choose non-alcoholic drinks, preferably cool water – tap water temperature is suitable. Avoid drinks containing caffeine, alcohol, or high amount of sugar, as these can increase fluid loss from the body. Avoid ice-cold drinks, as they may irritate the digestive system. Drink fluids even if you do not yet feel thirsty. The amount of fluid needed depends on metabolism, food intake, environmental conditions (temperature, humidity, etc.), physical activity, sweating, health status, and other factors. Fluid requirements increase substantially during increased physical activity. For adults, the usual daily fluid intake from beverages is approximately 1.5 litres; during hot weather, requirements are higher, at around 2 litres per day, and even more during physical exertion. The body signals its hydration status through thirst, the frequency of urination, and urine colour. Urinating infrequently and having darker urine are important signs that more fluids should be consumed. Warning: If your doctor has advised you to limit your fluid intake, or if you are taking diuretics, consult your doctor about how much fluid you should drink during hot weather. Drink more fluids during physical activity. During prolonged or strenuous exercise, use rehydration drinks to replace electrolytes lost through sweating.
Help others:
- Some people are at greater risk. Pay particular attention to signs of heat-related illness in infants and young children, older adults, pregnant women, people with disabilities, and people with chronic conditions, especially those with heart disease or high blood pressure. Call or visit people who live alone and may need assistance.
- Never leave anyone in a parked, enclosed vehicle.
- If someone becomes overheated, move them to a cooler place (into the shade or an air-conditioned or cool indoor space). In case of heat stroke, seek medical help immediately and continue cooling the person while waiting for assistance. If the person is unconscious, do not give them fluids.
- Consult a doctor if you experience unusual symptoms that do not improve or that become worse.
Remember:
- Protect yourself from the sun. During the hours when the sun is strongest (between 10 a.m. and 5 p.m.), seek shade whenever possible. Protect yourself with sunglasses, a hat or other head cover, suitable clothing, and broad-spectrum sunscreen (protecting against UVA and UVB rays) with a sun protection factor (SPF) of at least 30. The SPF number indicates the level of UVB protection, while the UVA symbol indicates protection against UVA rays. Apply sunscreen to exposed skin that is not covered by clothing (e.g. the face, ears, and backs of the hands).
- Pay attention to food safety. In hot weather, food spoils more quickly, increasing the risk of infection and food poisoning. Store food in the refrigerator. Take particular care with meat, perishable meat products, and food containing eggs or milk proteins. Wash fruit and vegetables thoroughly.
- Store medicines at the appropriate temperature in accordance with the manufacturer’s and pharmacist’s instructions. Follow your doctor’s advice.
- Follow weather forecasts and warnings through public information channels.
