Heat waves and how they impact children

Heat stress caused by extreme temperatures is putting more children at risk each year.

Climate change is raising global temperatures and causing historic heat waves. More countries are facing hotter days more frequently, with more intensity and for longer periods.

The heat stress caused by exposure to heat waves can negatively affect health and well-being, especially for infants and young children.

A third of the world's children experience 4-5 heat waves per year, on average. This means exposure to at least one of the following high-heat conditions:

• Temperatures over 35°C for 83.54 or more days per year;
• A heatwave that lasts at least 4.7 days or longer; or
• Temperatures 2°C or more above the local 15-day average.

By 2050 almost every child in the world - nearly 2.2 billion children - will be exposed to frequent heat waves.

Heat waves: Fast facts

What is a heat wave?

A heat wave is any period of three days or more during which the maximum temperature is higher than normal (in the top 10 per cent of the local 15-day average. Humidity can add to the temperature causing it to feel much hotter.

What is heat stress?

Heat stress is the stress caused to the body when it is unable to remove excess heat.

Exposure to high temperatures and humidity, which when intensified by physical exertion, overwhelms the body's ability to cool itself. This can lead to heat-related illnesses which can range from mild, like heat rashes in infants, to more serious life-threatening outcomes, like heatstroke and a high risk of organ failure.

Why are children more at risk?

Children are more vulnerable to the short- and long-term effects of heat stress.

Children sweat less per kilogram than adults and have a higher metabolism, which means they get hot quicker.

They also spend more time outdoors than adults for play, sports and other activities, putting them at greater risk for heat exposure and injury.

While playing or exercising, children are less likely to rehydrate, which can be dangerous and even fatal especially when it is excessively hot outside.

How do heat waves impact infants and babies?

Infants and young children cannot regulate their body temperature as well as adults because their bodies have more internal heat to begin with and absorb more heat from the environment.

Babies' immune systems are still developing, making them less capable of fighting off the symptoms of heat stress.

Heat stress in pregnancy can put the baby at risk of low birthweight, early birth and even stillbirth. It can also cause health problems for mothers.

How extreme heat affects children

Extreme heat poses unique risks at different stages of childhood. For example, babies and young children under age 5 are the most at risk of increased heat-related mortality and morbidity, while adolescents are more likely to experience exertional heat-related injuries.

Extreme heat can have serious effects on children's health, mental well-being, education and even nutrition.

Health

Heat stress can lead to heat strokes and diarrhoea caused by dehydration. It can lead to an increased risk of chronic respiratory conditions, organ dysfunction like kidney failure, and chronic issues due to congenital defects.

Nutrition

Heat waves make droughts worse, adding to crop failure and threatening children's access to food and water. Food insecurity caused by heat waves has severe impacts on child nutrition.

Education

Heat waves are linked to lower school attendance. High air temperatures and lower hydration are known to affect children's ability to concentrate. These can impact overall school achievements.

Mental health

High temperatures are linked to increases in mental health problems in children and adolescents. Heat can lead to high stress and poor sleep. These in turn can make episodes of depression and post-traumatic stress disorder more likely to occur.

How to keep children safe from heat stress

Recognizing early signs of heat-related illness and prevention are key

Here are some ways to keep children safe and comfortable during a heat wave:

• Keep a close eye on their activities even if they are playing indoors.
• Monitor for early signs and symptoms of heat illness.
• Avoid the outdoors during the hot midday and afternoon hours.
• Help them to slowly adjust into exercise or any physical activity.
• Encourage them to rest and cool off in shade when they start to feel hot.
• Remind children to drink water frequently to maintain hydration.

Infants and babies

• Create cooler places for infants and children.
• Consider bundling infants loosely during the hot season to allow them to cool off naturally.
• Lactating mothers should continue breastfeeding throughout the hot season; breastfed infants should not be supplemented with water during this time.
• Pregnant women should always stay well- hydrated.

What needs to happen

UNICEF calls on governments and partners to take urgent action

As heat waves become more frequent and last longer, the need for urgent action grows stronger. Preparedness can protect vulnerable populations, especially children.

UNICEF and partners are calling on governments to ensure that:

1. Frontline health workers are educated in recognizing the symptoms of heat stress and how they vary among infants, small children, pregnant women and the general population.
2. Health facilities are equipped with the proper equipment to rapidly cool heat victims - sufficient ice, chilled fluids, ventilators and more.
3. Healthcare systems are connected to meteorological services in high-heat regions. This will allow for health systems to receive advance notice on the next heat wave and prepare staff and vital equipment for a potential surge of patients.
4. Health facilities have cool public spaces where people can remain safely during a heat wave and without increasing the risk of spread of infection.