-Johnathon D. Anderson, PhD, Assistant Professor, University of California Davis Medical Center and Adviser to: Nature’s Lab Preschool
Does your child's daily routine encourage physical activity? Or are they stuck in a rut, or even in a school system, that leaves them very little time for exercise?
A study of 122,000 people was just reported in the prestigious Journal of the American Medical Association, which found that not exercising is worse for you than taking up smoking (Mandsager 2018).
Physical activity is a potent remedy for poor health, but exercise for children is important for other reasons too. Exercise enhances brain growth and boosts cognitive performance (Woost 2018). It helps kids focus and learn (Cotman 2007). So unfortunately when we create environments that prevent kids from being active, we are undermining their health, and making it harder for kids to succeed in school and in life.
One early study from the 1990’s compared sedentary mice with mice that ran each night on a running wheel (van Pragg 1999). The mice who were allowed to exercise showed substantial brain growth compared to the mice not allowed free access to exercise equipment. The region most effect in their brains was the hippocampus, which is crucial for learning and memory. The physically fit mice also had neurons in their brains that were measured to be considerably more efficient at communication and they performed much better on spatial learning tasks (finding their way through a maze).
We now know from human studies as well that exercise tells your body to make a variety of growth factors (eg IGF, VEGF) and neurotrophic factors (eg BDNF) that are similar to fertilizer for the brain allowing it to grow bigger, stronger and run more efficiently (Cotman 2007). Numerous studies have now verified these findings and we now know that physical exercise increases neurogenesis, synaptogenesis, and long-term potentiation (LTP). Moreover, exercise-evokes increases in cerebral blood volume. However, neurogenesis only partially explains exercise-induced effects on brain structure and function. Changes in tissue density and myelination (critical to brain function) are additional candidate mechanisms that underlie exercise related beneficial changes to brain physiology.
Some studies also suggest that exercise can make children more focused and less impulsive. When kids have been challenged with cognitive tasks that require lots of concentration and attentional control, individuals with higher aerobic fitness have performed with more accuracy, and sometimes faster reaction times, too (Moore 2013; Wu 2011; Voss 2011; Hillman 2005; Hillman 2009; Raine 2016). For example, school children were asked to view some images of animals and make quick judgments about them ("Is it a cat or a dog?"), physically fit kids had faster reaction times, and their brains showed evidence of more extensive processing during the task (Hillman 2005). Other brain research suggests that fit kids are better at filtering out task-irrelevant information (Kamijo 2015).
Studies also indicate that fit children tend to have greater brain volume in the hippocampus, a brain region associated with memory (Chaddock-Heyman 2014), and these kids show signs of enhanced long-term retention. Kids memorized new places on a map equally well, regardless of their fitness levels. But when they were tested on their retention the following day, the higher fitness children performed better (Raine 2013).
In one recent experiment, kids who ordinarily performed poorly on attention tasks improved their accuracy when tested shortly after "moderate acute exercise" -- 20 minutes of walking on a treadmill (Drollette 2014). Another experiment randomly assigned kids to one of three morning school sessions: 1.) sitting all morning, 2.) getting a 20-minutes of physical activity, or 3.) getting two 20-minute rounds physical activity bout.
The kids who got two bouts of morning exercise performed better on test of attention, and this was true even after the researchers adjusted for baseline differences in attention and children's involvement in sports (Altenburg 2015). When researchers tested the effects of short-term exercise on kids diagnosed with ADHD, they found that aerobic activity gave these kids a special boost, altering their brain activity in ways that might enhance self-discipline (Pontifex 2013). These studies address immediate, short-term responses to exercise, and lend support the idea that school recess periods -- breaks for play and physical activity -- can enhance attention in the classroom. But there are also studies that address long-term benefits of exercise for children.
For instance, what happens if you enroll previously sedentary kids in a program of daily physical exercise? One randomized, controlled study of overweight children found that 40 minutes a day of aerobic exercise improved executive function, that aspect of intelligence that helps us pay attention, plan, and resist distractions (Davis 2007). Another experiment replicated these results, and found that 13 weeks of aerobic exercise was also linked with improved math skills and increased activity in the bilateral prefrontal cortex, a brain region associated with executive function (Davis 2011). Another recent study of more than 220 school children found that kids assigned to engage in 60 minutes of daily, after-school aerobic activities performed better on tests of focus and cognitive flexibility-- switching between tasks while maintaining speed/accuracy (Hillman 2014). One experiment found that a 20 minute session of walking boosted children's subsequent performance on tests of reading, spelling, and arithmetic(Hillman 2009). Another study found that kids who exercised 10-20 minutes prior to a math test outperformed kids in sedentary control group (Howie 2015).
After four months of weekly high intensity exercise, these kids performed better than other kids on tests of cognitive ability and earned higher grades at school (Ardoy 2014). Adolescents assigned to less intense exercise workouts showed no showed no cognitive improvements over kids in the control group (Ardoy 2014). Recently, kids who were assigned a daily schedule with more physical activity breaks outperformed their control-group peers in mathematics and reading (Tomporowski 2016). When researchers conducted a meta-analysis of 59 studies published over the previous 60 years, they found that physical activity has a decidedly positive effect on children's achievement and cognitive outcomes (Fedewa 2011).
So school policies aimed to cutting recess or PE -- in order to make more time for academics -- are misguided. We've got nothing to lose by encouraging kids to exercise, and much to gain. But there’s a catch: Exercise should be fun. In fact, play--like exercise--is good for the brain. The most effective forms of exercise for children combine both high levels of physical activity and elements of play and this stretches children to grow both physically, cognitively and emotionally. For all these scientific reasons Nature's Lab has created fun, and ample spaces, full of opportunities for all children to engage and excel in all developmental areas.
Stay tuned for more articles
References
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