Warming global temperatures — fueled by climate change — are making children less physically fit and more obese than ever before, a new study has found.

And it’s a two-way street: physical fitness is also key to tolerating higher temperatures.

A less active lifestyle caused by higher temperatures is putting kids at greater risk of suffering from heat-related health problems, including dehydration, heat cramps, heat exhaustion and heat stroke, according to the study, published in the journal Temperature on Friday.

“As the world warms, children are the least fit they have ever been,” author Shawnda Morrison, an environmental exercise physiologist at Slovenia’s University of Ljubljana, said in a statement.

“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,” she added.

Today’s climate change policies are failing to address child health needs, Morrison argued, stressing the critical nature of encouraging kids to make exercise an everyday part of their lives.

Morrison drew her conclusions by combing more than 150 scientific studies into how children maintain physical activity and cope with heat, as well as how the situation might change as global temperatures rise.

Among her principal findings was that children’s aerobic fitness is 30 percent lower than that of their parents at the same age. Meanwhile, most children are failing to meet the World Health Organization’s guidelines of partaking in about an hour of physical activity each day.

Physical inactivity grew worse, particularly in Europe, during the coronavirus pandemic, when schools and other institutions shut down, according to the study.

Morrison highlighted previous research indicating that emergency departments at children’s hospitals in the U.S. revealed higher attendance on hotter days. Younger children were especially likely to require care.

She also probed findings from a study of 457 primary schools in Thailand that determined that overweight students were more than twice as likely to encounter difficulties regulating body temperature when exercising outdoors as those of normal weight.

As temperatures climb around the world, Morrison warned that parents may increasingly decide that it’s “too hot to play” outside.

In turn, this could mean that unfit children could face greater difficulties meeting the minimum physical activity levels required to stay healthy, according to the study.

With changes in weather patterns expected to cause outbreaks of new diseases in the human population, movement restrictions aimed at containing such illnesses could also harm children’s fitness, the research found.

Morrison identified physical education classes to be the most cost-effective way to equip children with the tools they need to exercise throughout their lives. Families can also play a key role in encouraging such activity, according to the study.

“Do what you love to do, whether it’s a family bike ride or rollerblade, a stroll through the woods or walking the dog,” Morrison said.

“Try not to completely avoid the heat but choose times of the day that are less hot (mornings/evenings) to keep active, since we need to keep ourselves moving in this new warming world,” she added.