Kids who get plenty of exercise are not only healthier, they are also smarter. And the benefits are lifelong. New research tells us why.
Dona Suri
To write The History of Sedentary America we don’t have to go back very far.
- By 1955, half of American homes had a TV set; by 2022 the percentage rose to 96% with many homes having multiple television sets.
- In 1984, only 8 percent of households had a computer; by 2000, about half of all households (51 percent) them.
- Computers in schools for instructional purposes really took off in 1991 and it is now universal.
- In 1996/97 mobile phones were at the very start of their upward trajectory: ownership stood at 16% of households; by 2006/7 the figure was 80%. That includes children: at present 42 percent of kids have a phone by age 10; by age 12, it’s 71 percent and by 14, it’s 91 percent. Today, less than 3 per cent of Americans do not own some type of mobile phone. Most of this 3 per cent is comprised of individuals who are in prisons or mental institutions.
- In 2013, Microsoft launched the first X-Box.
A considerable amount of daily exercise was simply built-in to the lives of persons born before 1963.
For Generation X – roughly defined as persons born between 1965 and 1975, exercise time started to decline thanks to television and the computer.
The mobile phone, a device that often renders people im-mobile, had its foot in the door by the time the Millennials came along.
And from the first decade of the 2000s to the present, gaming (and the X-Box) is ubiquitous.
So, within the short space of only about four decades, we have gone from a situation when the routine of daily life involved exercise as a matter of course, to a time when whether to get exercise or continue sitting on the ever-broadening backside involves choice, motivation and finding time.
For adults, the U.S. Department of Health and Human Services recommends a minimum of 150 minutes of moderate-intensity aerobic physical activity each week, as well muscle-strengthening activities. That’s only 20 minutes of exercise a day, but look at the statistics from the Centers for Disease Control and the National Institutes of Health. …
- About 79.7 per cent of Americans report that they cannot find either the time or the motivation to undertake any kind of exercise. Not even walking.
- Of the 19.3 percent who do exercise, out of every ten persons who exercise or play some sport, three will be men and only two will be women. The DHHS recommends that children get an hour of physical activity every day, but less than 25 percent meet that target.
- Lack of exercise shows up clearly in America’s obesity epidemic; today more than four out of ten Americans qualify as obese, with one in ten making it to the severely obese category. Data from 2017-2020 for persons between 2 and 19 years of age the prevalence of obesity was 19.7%.
The physical and psychological benefits of exercise are undisputed. It’s not that people don’t know. One would like to say “Alright, forget about all the couch-potato adults; let’s provide every exercise and sports opportunity to children and adolescents. When they are in school, the exercise habit can be built into the curriculum. There is a good chance that the kids will retain that habit as adults.”
The more medical researchers investigate the effects of exercise on young people, the more reasons we find to promote it – strongly.
The most obvious benefit is healthy weight. Obese children and adolescents not only have health issues, psychological issues are also part of the package. Over the past ten years, medical research has found some not-so-obvious benefits of young-age exercise.
Back in 2010 Swedish doctors at the Sahlgrenska University Hospital (University of Gothenburg) conducted a huge study (1.2 million Swedish men doing military service who were born between 1950 and 1976; results of both physical and IQ tests when the men enrolled were analyzed). They found a clear link between good physical fitness and cognition. The strongest links are for logical thinking and verbal comprehension. But it is only fitness that plays a role in the results for the IQ test, and not strength. The study also found that the young men who improved their physical fitness between the ages of 15 and 18 also increased their cognitive performance. The doctors concluded that physical activity at a young age improved cardio-respiratory fitness which in turn affected the structure and function of the developing brain, especially regions such as the hippocampus, which is involved in memory, and the prefrontal cortex which is involved in our ability to think, reason and commit purposeful action based on thought and not impulse. The prefrontal cortex does not complete its formation until the early 20s. Exercise increases metabolic demand and, in response, the brain increases angiogenesis – building more capillary beds to transport blood and oxygen to different regions. It also increases the formation of synapses between neurons, increasing the ability of different parts of the brain to talk to each other.
And it’s a lasting benefit: the neuro-protective qualities of exercise are present throughout life, with individuals in their 60s and 70s who exercise having a lower risk factor of developing Alzheimer’s disease.
It’s a lifelong benefit in another respect too. People who have grown up doing regular exercise are more motivated to get out there and exercise as adults. Chalk it up to brain chemistry. Anybody who has ever followed a regular exercise routine knows that using the muscles and raising the heart and respiratory rate increases the levels of neurotransmitters such as dopamine and serotonin. These chemicals are “rewards” that keep people coming back for that feel-good exercise high.
A surprising benefit came to light in 2017. Researchers, led by molecular geneticist Dr Justin O’Sullivan, at the Liggins Institute at the University of Auckland, were investigating bone health and metabolism. The research team compared the bone health and metabolism of rats across different diet and exercise conditions, zeroing in on messenger molecules that signal the activity of genes in bone marrow. They took three groups of young rats: one group got a high-fat diet and an exercise wheel in their cage, one group got a high-fat diet but no wheel, and one group got a regular diet and no wheel.
In the high-fat-and-wheel group the early extra physical activity caused inflammation-linked genes to be turned down. Exercise altered the way the rats’ bones metabolised energy from food, changing energy pathways that disrupted the body’s response to a high-calorie diet.
(High-fat diets early in life are known to turn up, or increase the activity of other genes that cause inflammation. Inflammation is the body’s natural self-protective response to acute infection or injury, but the ongoing, low-grade inflammation linked to high-fat diets can harm cells and tissues and raise the risk of obesity, heart disease, cancer and other diseases.)
“What was remarkable was that these changes lasted long after the rats stopped doing that extra exercise – into their mid-life. The bone marrow carried a ‘memory’ of the effects of exercise. This is the first demonstration of a long-lasting effect of exercise past puberty. The rats still got fat, but that early extra exercise basically set them up so that even though they put on weight they didn’t have the same profile of negative effects that is common with a high fat diet. It also strongly emphasises the health benefits of exercise for children.”
The rat study prompted researchers to start investigating children who begin intense exercise very early in life. They found persistent changes in gene expression and big differences in their bone mass, density and mineral content compared to those who had not been involved in exercise. Even if the exercise ceases in adulthood, these differences persist for 10 years or more, especially if the exercise began before puberty.
As well as making those individuals less prone in later life to bone diseases such as osteoporosis, these changes also have implications on the way food is processed, in particular, high-fat diets. Our bones are far more involved in energy metabolism than we might think, and the gene expression changes induced by early-life exercise affect a variety of pathways that alter the body’s inflammatory response to a high-calorie diet. These changes are retained in the bone marrow into adulthood, making those children less susceptible to inflammatory-related diseases such as diabetes and cancer when adult.
The next step down this path of investigation is to evaluate what happens to children in the womb when their mothers exercise. The doctors reason that since the mother shares her circulation with the unborn child, all kinds of changes are passed on in terms of hormone levels or blood lipid levels, all of which affect energy storage, oxygen capacity and muscle health of the child at birth. Results of this study are awaited.
If a mother-to-be can set her child up for lifelong health by exercising, it really emphasizes that when it comes to exercise, there’s no such thing as too young. And it certainly fits in with what we might call “Nature’s Plan”. Here’s some more statistics (from a study at Duke University) to explain what we mean by that …
Infants between the ages of 9 and 15 months expend a stunning 50 percent more energy in one day than adults do, adjusted for body size. They use up energy even faster than pregnant women and teenage boys.
Where is all that energy going? Lean tissue in organs uses more energy than fat, and children’s energetically expensive organs take up more of their body mass than in adults. When the scientists plotted metabolic rates across life span, they found infants are born with the same metabolic rates as their mothers, when adjusted for their smaller body size. Then, between 9 and 15 months, they rev up their cells to burn energy very fast.
The key energy sucker is the growing brain, although other organs and the immune system are also high consumers. Brains of young children consume a stunning 43 percent of all energy used by their bodies. Children’s metabolic rates stay high until age 5, but the rate slowly begins to glide down until it plateaus around age 20.
Moral of story:
If children are to grow up smart and healthy, they need plenty of exercise along with plenty of good food.