Children in hunter-gatherer societies have a completely different experience with physical activity than we do – and we should be taking notes, according to a new study, not yet peer-reviewed, from researchers in the UK.
There are many advantages to living in a developed region. TV, for example, is one; so is the internet; the high-tech smartphone you’re reading this on, and the indoor plumbing you’re likely utilizing as you do so.
But with affluence comes disease. It’s always been the case: in the 18th century, illnesses like gout were considered “rich man’s diseases”; today, the so-called “diseases of affluence” include diabetes, hypertension, heart disease – basically, any non-communicable disease caused by an overabundance of nutrition and an underabundance of exercise.
The trouble is, those conditions are virtually unavoidable for many of us. Four out of five jobs in the US involve sitting down for most of the day, and the average American has to drive for an hour a day to even get to work and back. Meanwhile, family time is often organized around sitting and eating; everybody’s tired; there’s a new season of Supernatural being teased – all in all, it’s no wonder that less than one in four of us are managing to also get the amount of aerobic and strength exercise recommended by health experts.
Unfortunately, living an almost entirely sedentary life is what medical professionals refer to as “a bad idea.” It’s estimated that up to one in eight early deaths can be attributed to physical inactivity; regular exercise, on the other hand, can increase your life expectancy by close to seven years. That leaves researchers with a dilemma: there’s currently “significant interest in examining the cultural factors driving increased activity,” the preprint explains, but the only people available to study are unsuited for the job.
“Research that has attempted to [study] this has largely done so using culturally similar, highly sedentary, high-income populations,” write the authors. “These populations represent a narrow fraction of human cultures, for whom daily calorie acquisition is decreasingly dependent on physical activity, with labor increasingly sedentary and foraging replaced with market-bought goods.”
To combat this lack of information, researchers have turned to modern hunter-gatherer societies, among others, to compare our post-industrial lifestyles. The Hadza people of Tanzania, for example, get close to 15 times the amount of moderate to vigorous physical activity as the average American; other hunter-gatherer communities are similar, and all “appear to have exceptionally low rates of non-communicable ‘diseases of modern life’, including low rates of obesity, type II diabetes, hypertension, and auto-immune disorders,” the team points out.
But previous studies have neglected something very important, they argue: children. “Hunter-gatherer childhoods are marked by learning of skills such as gathering wild plants, hunting animals, collecting honey and caterpillars, fishing, childcare and domestic activities,” the researchers explain, while in high-income populations, “up to 80 percent of children globally fail to meet recommended physical activity guidelines.” And, since the amount of exercise you get as a kid is a pretty good predictor of how active you are as an adult, it’s probably wise to take a look at what’s going on, and why.
There were three cohorts of children involved in the study: a US group, whose data came from the American National Health And Nutrition Examination Survey (NHANES); a UK group, which used information from the British Millennium Cohort Study (MCS); and a group from the BaYaka people in the Republic of Congo, who were monitored using wrist-worn accelerometers.
The results couldn’t have been more different. Not only were BaYaka children far more active than their UK and US peers – “the average day included over three hours of MVPA [moderate and vigorous physical activity],” the authors note, which is “a volume triple the WHO recommendations for children” – but they also showed the exact opposite trend in activity levels with age.
“Amongst the BaYaka, older children were more active than younger children,” the researchers discovered. “This is in stark contrast to children in the US sample presented here and other high-income populations where volumes of physical activity commonly peak in early childhood (ages 5 to 6) and decline from then, until reaching a low plateau in adulthood.”
The lesson? Well, apart from the obvious – that those of us in high-income nations have moved a long way away from our evolved niches, and our health is both benefiting from that change and suffering from it, too – it may be that Bart Simpson had it right all along. Perhaps school is making us sick.
“The observations in the BaYaka and the sampled high-income populations suggest that formal schooling may promote inactivity in children, limiting their autonomy by mandating long periods of sedentary activity,” suggest the researchers. “This schooling structure might contribute to increasing mental health problems and decreased child happiness observed in high-income populations.”
But what’s the alternative? Well, to be honest, it sounds rather nice.
“Without formal classrooms, BaYaka children choose their activities, with no imposed sedentary behavior,” the team point out. “Their daily activities, unlike American children’s regimented school schedules, are more variable and reflect an ecology of autonomous play, foraging, and rest […] Implementing BaYaka perspectives, like breaking up prolonged bouts of sedentary behavior as employed in forest-school and Udeskole (outdoor-school) programs has been observed to increase overall activity.”
The preprint can be found on BioArXiv.