Children’s fitness and activity levels have declined worldwide. Photo / 123RF
Children today are less fit than those of previous generations, which will not serve them well as adults in a warmer world. By Nicky Pellegrino.
The heat wave which persisted during the European summer
harmed people’s health. Extreme heat can trigger a range of stressful conditions, such as heatstroke, and as the body works very hard to maintain its core temperature at normal levels, this puts pressure on the heart, lungs and kidneys.
High temperatures increase the risk of heart disease and death, and studies have shown that the burden of heat-related heart attacks is likely to increase with global warming of 2-3°C. So, as the planet warms, future generations will need to be physically fit and maintain optimal cardiovascular health if they are to thrive.
Unfortunately, the opposite is happening, says cardiovascular and environmental physiologist Shawnda Morrison. Morrison earned her PhD at the University of Otago and is now based in Slovenia, where she is involved in SLOfit, a longitudinal study of children’s physical and motor fitness.
“Every Slovenian schoolchild is tested once a year in April,” she says. “They do a battery of fitness tests in their physical education classes, so we have a lot of data.”
Children’s fitness and activity levels have declined worldwide, with a 2018 WHO report finding that 80% of children aged 11-17 are not physically active enough. Evidence from SLOfit showed that this decline accelerated during the Covid-19 shutdowns.
“We found the greatest decrease in children’s fitness in the 30 years of record of this longitudinal monitoring, and it was in all areas – aerobic fitness, musculoskeletal flexibility, reaction time: all the different components.”
Families may have gone out for walks together in their neighborhoods during the shutdowns, but the intensity of the exercise the children were doing was not high enough to maintain their physical fitness compared to the workouts that the classes school physical education or organized sports would have provided.
Morrison, who is based at the University of Ljubljana’s Faculty of Sports, wanted to delve deeper into fitness as global temperatures rise. In a review of more than 150 studies, published in the journal Temperature, she found that the aerobic capacity of children is 30% lower than that of their parents at the same age.
In the research, she highlights a study of 457 primary school-aged boys in Thailand, which found that overweight youngsters were more than twice as likely to have difficulty regulating their body temperature when they exercise outdoors than those of normal weight.
Children have a slightly different thermoregulation from adults. They sweat less and instead lose heat by increasing blood flow to the skin, a process that can make the heart work harder. When they’re physically fit, their heart is stronger and able to pump more blood per beat, and so their blood vessels will be more responsive and efficient, Morrison says. Additionally, they are more likely to grow into fit, active adults who will be better able to tolerate higher temperatures.
“Yet as the world heats up, children are the least fit they’ve ever been.”
How do we turn things around? Morrison has some ideas.
“We have to build our society around the concept that we have to move our bodies,” she says. “This includes mandatory physical education lessons in every school taught by physical education teachers. Parents have a huge role to play, especially with children aged 3 to 10. We need to do physical literacy a priority. If you know how to catch, run, jump, swim and do the basic movements, then you will enjoy moving. If you don’t feel confident, then you could be sedentary all your life.
She advises no more than an hour of recreational screen time a day — and that means any screen — and practices what she preaches. Morrison doesn’t own a smartphone and even on the hot days this summer, her two young children had the opportunity to run around in the relative cool of the evening, providing them with plenty of water to stave off dehydration.
New Zealand, with its wide open spaces, is well placed to make a positive difference to the fitness and future health of our children, she says.
“But parents have to be extremely diligent in modeling correct behavior. And kids shouldn’t have smartphones.”