Also, I’m not sure anybody actually knows what “intelligence” is…
While I’m afraid nobody can realistically work on 4 week timescale, there is a simple (and free) way to help you think, learn and remember more effectively. Evidence is mounting, which suggests that both children and adults can improve their cognition simply by increasing their levels of activity.
The idea that exercise improves cognitive performance has been around for a while, but hasn’t really taken hold as much as you’d expect. In general, until recently, studies on the effects of exercise and cognitive performance have focused on adults. This is quite surprising, as certain areas of the brain associated with cognition continue to develop throughout childhood and adolescence. Therefore, the greatest capacity for change happens during this time. In fact, one key area, the pre-frontal cortex, doesn’t reach full (and largely final) function until your early 20s.
One aspect of cognition that has been studied with respect to exercise in both children and adults is “executive control”. Executive control involves:
- Inhibition (the ability to maintain focus and ignore irrelevant stimuli).
- Working (short-term) memory.
- Cognitive “flexibility” (the ability to change perspective and focus of attention).
Levels of executive control correlate better with academic performance than traditional IQ tests. Executive control has been shown to be higher in fitter children, as well as lower in children with higher body fat levels. As children in the Western world become more sedentary and overweight, we are seeing a parallel decrease in cognition and overall academic performance. Because of this, many areas of research are focused toward developing a picture of how activity might change the way we think.
To build on the above information, two studies investigating fitness and cognition in children have been published recently. Both of them suggest that fitter children will learn better and perform better academically.
The first study took children aged 9-10 and investigated how their fitness might affect their ability to first learn, and then remember. “Fitness” was assessed with a treadmill test measuring VO2max, as is done in athletes. The more oxygen your body can use when exercising at full effort, the higher your VO2max, and the fitter you tend to be. Forty-eight children were studied, half of which had above-average fitness for their age group, with the other half below-average. Over subsequent days, the children were asked to learn the names of regions on a fictional map, either by just studying the names, or using a system where they were tested during the learning period (which makes learning easier). They were then assessed by being asked to remember the regions they learned with either free-recall (harder), or with some prompting (easier).
Previous work has suggested that fitter children tend to have better memories, but this particular study found that the main difference between the two groups was that fitter children performed better when the test was at its hardest – remembering the map without any prompting, after learning the regions by studying only. They found that fitness had no effect on performance in the two different types of recall test (with or without prompting), which suggests that:
Fitter children learn (process and store) information better than unfit children, particularly in more challenging situations.
Unsurprisingly, all of the eight studies included in the analysis showed that physical activity was beneficial. Overall, they found that:
- There was even an increase in academic achievement when physical activity was increased at school by reassigning up to 25% of curriculum time away from the classroom!
- Fitter children showed better ability to control their attention and focus.
- Physical activity reduced depression and increased self-esteem.
The ways in which studies increased physical activity did differ greatly, including randomising children to receive 150% extra physical activity at school, with sports such as gymnastics and swimming. Another study changed regular physical education (“PE”) classes to a more structured programme of basketball, volleyball and jogging, for a total of 90 minutes per week.
The authors of the study then discussed in their conclusion that more rigorous studies are essential in order to determine the type of exercise, as well as intensity and duration of that exercise, which will provide the best benefit in the cognitive performance in children.
While further studies will no doubt take place, I would argue that it doesn’t matter!
In this meta-analysis, as little as 45 minutes of physical activity per week showed some cognitive benefit (not to mention many associated health benefits)! As so many different types of exercise “intervention” have been shown to work, there is only one essential take-home fact:
Getting children to move more, in any way, will make them think better and be happier!
Teaching old rats new tricks
OK, so you’re not in your teens anymore.... Does that mean you’ve peaked, and are destined to slowly, inexorably, lose your marbles over the coming years?
It is a sad fact that, as you get older, your hippocampi (you have one hippocampus on each side of the brain) shrink. Smaller hippocampi are associated with worsening memory, as well as a decrease in the ability to learn new tasks.
Contrary to what many of us were told as children, you are not born with a fixed number of brain cells, which then slowly die off as we subject them to television, beer and contact sports. Certain areas of the brain can continue to produce new neurons (also known as neurogenesis) almost indefinitely. However, we need to keep providing a stimulus to make sure that neurogenesis continues into old age.
Simple things like sleeping more can help prevent cognitive decline but, regardless of age, aerobic exercise will also improve memory and cognitive function.
Over the years, we have learned a lot about memory and cognition from animal studies. Giving rats and mice access to exercise equipment and increasing their physical activity allows us to then test their memory, as well as study changes in the brain. From work in “aged” animals, we know that:
- Fitter rodents learn better and have improved memory.
- Exercise increases the number of “growth factors” in the brain, which stimulates neurogenesis, and growth of new blood vessels.
- Exercise not only produces more neurons, but also increases the strength of connections between neurons, meaning they can communicate (and you can think) better.
More sweat = More hippocampus
Whilst data from rodents is interesting, the reason we do those experiments is to try and learn about what might be happening in our brains as we get older. Luckily for us, we see very similar results in humans.
A recent study took 120 adults in their 60s and randomised them to either aerobic exercise, or a light stretching session, three times per week for a year. At the end of the trial period, the study found that:
- Those in the aerobic exercise group had a 2% increase in the size of their hippocampi (measured on MRI).
- Over the same time, the stretching group saw a 1.4% decrease in hippocampal size.
- As hippocampal size increased or decreased, this correlated with an improvement or decline, respectively, in memory function.
Some say that “size doesn’t matter”. They’re lying. If you want your brain to stay fighting fit for as long as possible, you need a huge, pulsating, pair of hippocampi.
The effect of aerobic exercise was the equivalent of reversing 1-2 years of age-related decline in memory. Being fitter also protects your cognitive function. In the stretching group, those who were fitter to start with (as measured in a similar way to the treadmill test above), saw better retention of memory function over the year of the study.
In agreement with this, a study of older adults showed that those who exercised through life had less brain atrophy compared to those who had never regularly taken part in physical activity. Another study found that increased fitness in older adults is also associated with better performance in tests of learning, memory and executive function.
The best bit is that you don’t need to go running three times per week to see these benefits. After a gentle increase over the first two months, the exercise group simply performed 40 minutes of brisk walking, three times per week.
Similar improvements are seen in older adults who already show early signs of dementia. Sufferers of Alzheimer’s disease tend to have:
- Smaller hippocampi.
- Decreased blood flow to the areas of the brain associated with learning and memory.
- Lower levels of the “growth-factors” that promote neurogenesis.
As moderate-intensity exercise (such as brisk walking) increases blood-flow to the brain, as well as levels of these pro-neuron growth-factors, exercise could be an important way to prevent and slow the progression of dementia.
In fact, exercise provides a better improvement in cognition than traditional “brain-training” type games and puzzles. A meta-analysis published this year showed that doing brain training games makes you better at brain training games, but so far they show little carry-over to other aspects of brain function.
The brain can often be ignored in favour of the more “obvious” organs that become diseased with age, as you can accommodate a lot of damage and neuronal loss before you notice a difference.
Though most of the brain is more or less finalised by your late 20s, all of these studies suggest that we can still have a huge influence on the areas of the brain that are involved with learning and memory as we age. Something simple like walking for a couple of hours per week appears to be enough to prevent most of the age-related decline in cognition. It’s also probably not a coincidence that keeping up this level of activity will reduce your risk of obesity, diabetes, heart disease, strokes and cancer.
As we enter the winter months, this is the perfect time to wrap-up warm and enjoy some long walks.
No matter how old or young you are when you start, doing so will keep your brain firing for many more years to come.
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