It is no secret that exercise is essential for a healthy body. Adequate physical activity has been linked to improved cardiovascular health, weight management, enhanced sleep and better mental health, among other things.

Perhaps not as well known is the link between exercise and cognitive ability. The benefits of aerobic exercise for a healthy mind are increasingly evident.

Research is uncovering how it can help to improve memory – something all students want! A 2018 study, for example, found that just 10 minutes of mild exertion resulted in improved cognitive ability in healthy young adults.

Exercising your way to a healthier mind – how exercise improves memory

The study, published in Proceedings of the National Academy of Sciences, used functional magnetic resonance imaging to look at the brains of 36 young people shortly after 10 minutes of very light cycling on a recumbent exercise bike. They found heightened activity in the hippocampus and surrounding brain regions, plus better connectivity between the hippocampus and cortical areas that are linked to detailed memory processing.

“The hippocampus is critical for the creation of new memories; it’s one of the first regions of the brain to deteriorate as we get older,” project co-leader Michael Yassa told Science Daily. “Improving the function of the hippocampus holds much promise for improving memory in everyday settings.”

The University of California neuroscientist added that these changes may positively affect the brain long-term, but even 10-minute periods of exercise showed immediate results.

They also found that the participants who exercised performed better afterwards on a difficult memory test.

One way that exercise may improve memory is through triggering a protein that boosts brain cell growth. A study published in the journal Cell Metabolism in 2016 discovered that when muscles are exercised, they produce a protein called cathepsin B. It travels to the brain and triggers nerve cell growth in the hippocampus.

Part of the study involved putting previously inactive students through four months of regular aerobic exercise. Researchers found that as the “couch potatoes” became fit, the more cathepsin B they had in their blood and the better they performed on memory tests.

“Overall, the message is that a consistently healthy lifestyle pays off,” senior author Dr Henriette van Praag, a neuroscientist at the US National Institute on Aging told the UK Telegraph. “Moreover, in humans who exercise consistently for four months, better performance on complex recall tasks, such as drawing from memory, is correlated with increased cathepsin B levels.”

She added that their study supports the theory that more substantial memory changes occur with maintaining an exercise program long-term.

Similar results have been found in school children. A study published in Brain Research used MRI to compare the brains of higher- and lower-fit 9- and 10-year-olds. The scientists found that children with higher levels of fitness had larger hippocampi and performed better on relational memory tasks compared to less fit children.

Physical activity and school performance

In addition to improving memory, exercise has other performance-boosting benefits for cognitive ability, such as enhancing focus and concentration.

For example, a 2016 study examined the attention of Dutch children aged 10-13 years during a morning at school. They compared attention across three groups: one that sat all morning; a second that completed a 20-minute bout of physical activity after 90 minutes; and a third that completed two 20-minute physical activity bouts – one each at the start and after 90 minutes.

The children who performed the two bouts of moderate-intensity physical activity had significantly better attention scores compared to the other groups.

Another large randomised controlled trial published in the journal Pediatrics looked at the effects of daily sports classes in 221 children aged seven to nine. They were randomly assigned to a nine month after school physical activity program or a wait-list control.

Aside from improved physical fitness, the activity group had enhanced cognitive performance and brain function during tasks requiring greater executive control (the ability to use complex mental processes and cognitive abilities, such as working memory and impulse inhibition). They got better at ignoring distractions, maintaining attention, multitasking, and manipulating information mentally.

Several other studies have linked cognitive ability with aerobic exercise, possibly through the action of a substance called brain-derived neurotrophic factor, which stimulates the growth of nerve cells.

Importantly, the exercise doesn’t need to be exhausting to be beneficial. In fact, a UK study involving more than 11,000 school students found that their best responses to tests occurred after physical activity that was set at their own pace, rather than exhaustive exercise.

How exercise reduces anxiety and depression and improves mental health and mood

Naturally, you want your children to have good mental as well as physical health. Exercise can help here, too. Evidence linking physical activity and mental health Is less well documented for children and adolescents but is increasing.

A systematic review published in May 2019 looked at 42 studies from 2010 to 2017 that explored the link between physical activity and depression, self-esteem, and cognitive function.

The findings confirmed the association between higher or improved fitness and physical activity and cognitive performance. They also found partial evidence for a causal association between physical activity and depression in young people.

An interesting related area is the association between screen time and mental health. For example, young people who spend seven hours or more per day on screens are more than twice as likely to be diagnosed with depression or anxiety than those using them for an hour per day, according to a study published in the journal Preventive Medicine Reports in 2018.

This research involved more than 40,000 young people aged 2 to 17 years. Scientists took measures of screen time (including mobile phones, computers, electronic devices, electronic games, and TV) and an array of psychological well being measurements.

They found that anything more than one hour per day of screen time was associated with lower psychological well being, including less curiosity, lower self-control, more distractibility, greater difficulty making friends, less emotional stability, being more difficult to care for, and inability to finish tasks.

In 14- to 17-year-olds, those using screens for seven or more hours per day were more than twice as likely to have been diagnosed with depression or anxiety than low users. They were also twice as likely to have been treated by a mental health professional or taken medication for a psychological or behavioural issue in the last 12 months.

Moderate screen time of four hours per day was also associated with lower psychological well being. Furthermore, children under ten having four or more hours of portable electronic device screen time daily are twice as likely to get insufficient sleep.

Some scientists even suggest that excessive screen time could cause permanent damage to children’s developing brains. “The ability to focus, to concentrate, to lend attention, to sense other people’s attitudes and communicate with them, to build a large vocabulary—all those abilities are harmed,” Dr. Aric Sigman, a Fellow of Britain’s Royal Society of Medicine, told Psychology Today.

How reducing screen time results in a more active lifestyle

Reducing screen time would therefore seem to be a no-brainer for a healthier mind and body. A 2018 study, for example, suggested that reducing screen time was important for helping adolescents to maintain a healthy weight.

While devices can be a great tool, the evidence for an active lifestyle as an educational strategy keeps stacking up. Current Australian guidelines recommend children aged 5-12 years should accumulate at least 60 minutes of moderate to vigorous physical activity every day, including various aerobic activities. Exercise that strengthens muscle and bone should be included at least three days per week.

They also recommend that use of electronic media for entertainment should be no more than two hours per day.

For further information, the Australian Government has developed guidelines to help young people establish healthy habits 24/7, including recommendations around physical activity, sedentary behaviour and sleep.