Record obesity puts children at greater risk in increasingly hotter weather, study warns

Record numbers of obese children around the world are more likely to suffer heat-related health emergencies as global temperatures rise, a researcher has warned.

Children take about 30 per cent less aerobic exercise than their parents when they were their age, according to data cited by environmental exercise physiologist Dr Shawnda Morrison.

Obesity puts children at greater risk of dehydration, heat cramps, heat exhaustion, and heat stroke, she said after a new comprehensive review of more than 150 studies on the topic.

Generally, children sweat less than adults and their hearts work harder to regulate their core temperatures – and this process to cool down the body is more taxing on the organs of obese children, she said.

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One study in Thailand – of 457 boys aged five to 11 – found that overweight children have more than double the difficulty in regulating their body temperature while exercising outside compared to their peers with normal body weights.

Another study of data from hospital emergency departments in the US found that children’s admission numbers were higher on the hottest days.

The research by Dr Morrison, from the University of Ljubljana’s faculty of sport, in Slovenia, also found that most children are failing to engage in an average of 60 minutes of physical activity every day as advised by the World Health Organisation.

She found that physical inactivity increased, especially in Europe, when schools and sports clubs were closed during the Covid pandemic.

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Dr Morrison said current climate change policies fail to emphasise the importance of physical activity to improve children’s resilience to heat, which she said becomes more crucial as global temperatures rise.

She said: “Fitter adults are better able to tolerate higher temperatures, due to a combination of physiological, behavioural and psychological factors.

“Yet, as the world warms, children are the least fit they have ever been. It is imperative that children are encouraged to do daily physical activity to build up, and maintain, their fitness, so that they enjoy moving their bodies and it doesn’t feel like ‘work’ or ‘a chore’ to them.”

Her warning comes as many parts of the world – including North America and western Europe – suffered amid extreme heatwaves this summer, with the mercury hitting 40C in the UK for the first time since records began.

Dr Morrison noted that many parents are afraid to let their children exercise outside when the weather is very hot, but advised families to allow the youngsters to play outdoors, do sports, or go for walks during cooler times of the day.

Dr Morrison is an expert in adaptive and integrative human physiology in extreme environments, with more than 20 years of experience in investigating sport performance, particularly in hot environments.

Her findings have been published in the peer-reviewed journal Temperature.