Exercise and brain fitness

"Exercise boosts brain power"

Learning changes the brain

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Cognitive exercises and everyday brain fitness

Source: Norman Doidge, Chapter 3, The Brain That Changes Itself (2007)

Experiences changes the brain, and we can take an active role in brain fitness. The brain has approximately 100 billion neurons. It "is not an inanimate vessel that we fill; rather it is more like a living creature with an appetite, one that can grow and change itself with proper nourishment and exercise." Studying a new subject, learning a new language or to play a musical instrument, enjoying hobbies that require us to think and reason are some of the everyday ways we use cognitive activities to challenge our brain and maintain brain fitness.

Programmed cognitive exercises cover a range of activities that promise to improve reaction time, visual and auditory processing, memory and recall, etc. When we are learning something new, acquiring a new skill, or even developing a negative behaviour pattern, we are changing the very structure of our brain. Brain maps are dynamic and the brain is constantly adapting itself. Hundreds of millions and possibly billions of synaptic connections between neurons that communicate with other neurons along pathways in our brain maps are being reorganized.

As brain maps are constantly changing, plasticity is competitive ("use it or lose it"). If we don't exercise the skills, abilities and behaviours we need to keep, their brain maps are taken over by the skills, abilities and behaviours we practice instead. The competitive nature of plasticity also explains why we have difficulty "unlearning" or breaking bad habits: "when we learn a bad habit, it takes over a brain map, and each time we repeat it, it claims more control of that map and prevents the use of that space for 'good' habits."

Cognitive exercises improve our brain when their design enables experiences "consistent with the laws that govern brain plasticity." Like physical exercise, cognitive exercises are most effective when they increase in difficulty and are maintained over a long period of time or incorporated in our lifestyle.

"The key in developing exercises is to give the brain the right stimuli in the right order with the right timing to drive plastic change." Exercises that work improve our ability to perceive and think more clearly and precisely, and to do more mental work with greater precision, speed and retention by training specific processing areas of our brain. They train our mental functions that apply to everyday life in the most efficient way. For PositScience, these include memory exercises, attention exercises, brain speed exercises, people skills exercises, intelligence exercises, and navigation exercises.

Physical exercise and the brain

Source: Sam Wang, The Neuroscience of Everyday Life (2010)

Sam Wang argues that, to boost brain fitness, physical exercise is a stronger intervention than cognitive exercises. He suggests that many of the benefits claimed for brain training software are not yet supported by strong scientific evidence. He believes that, with the exception of reaction time training, the benefits are small when training is specific to the tasks practiced, and that the benefits of cross-training are non-existent. "Some are inspired by science but not necessarily proven by science."

He concedes, however, that although the benefits of brain training exercises are relatively small, they are longer lasting because they involve "changes in synapses and neurons that are use-dependent and can last for a long time." The benefits of physical exercise are greater, but generally speaking, "typically last about as long as the exercise programs or up to some weeks afterwards . . . You have to keep on doing it."

Peer-reviewed scientific evidence has established that physical exercise significantly improves brain health and suggested that physical exercise can influence and slow down the effects of cognitive decline that accompanies aging, but exactly why is still not known. However, scientists generally agree that the benefits to brain health derive from increased blood flow to the brain and the secretion of neurochemicals that are beneficial to brain health and triggered by physical exercise.

So, although scientists have not yet worked out exactly how exercise works in the brain, several possibilities have consistently been indicated. (1) Exercise can increase the flow of blood to brain and improve brain function, just as it improves cardiovascular function. (2) Exercise triggers the secretion of BDNF (brain-derived neurotrophic factor), a growth factor that causes neurons to sprout new dendrites and create new synaptic connections. BDNF also promotes the growth of myelin, a thin fatty coat on the axons of neurons that speeds up the transmission of electrical signals. (3) Exercises can trigger biological changes in the brain - triggering naturally occurring brain chemicals like opiates and endorphins and changes in serotonin levels.

What's good for the heart is also good for the brain. Physical exercise, especially aerobic exercise, benefits all ages, ranging from children to the elderly. It improves cardiovascular function, reduces symptoms of anxiety and depression, and protects cognitive functions. Its effects on working memory, planning, and acting on those plans have been measured.

For adults 18 to 64 years of age, 2.5 hours weekly of moderate intensity exercise, or 75 minutes weekly of vigorous intensity aerobic exercise, or some equivalent combination of moderate and vigorous aerobic activity in episodes of at least 10 minutes spread throughout the week is recommended. Sam Wang suggests that 30 minutes at a time to get your heart rate up several times a week is enough exercise to protect your brain and reduce the risk of dementia, even if we start in middle age or later.

Everyday brain fitness

Cognitive exercises are big business and aren't all equally effective. Those that work are based on scientific research and experiments that have yielded consistent and measurable results after multiple testing. They must also have been verified by credible studies of different populations and conditions before and after individuals have practiced them.

Perhaps we may say the same about cognitive exercises as we could about the design, experience and effects of electronic games: they vary, some are better than others, and some people like them. There is little doubt, however, that a healthy skepticism is appropriate when our attention is drawn by advertisers offering science-based mental exercises to boost our brain power - especially when the the dollar cost is high.

It may also be worthwhile to note cognitive exercises are not defined or limited by computer software or electronic games. Activities and hobbies that require us to think and reason, and to engage our minds in active learning build and maintain brain fitness by changing our brain structures for lasting benefit. And even though scientists have not yet exactly explained the mechanism that enables physical exercise to benefit the brain, the health benefits of physical exercise are indisputable. If the health benefits of physical exercise last only as long as we keep exercising, what better reason can we have to introduce regular physical exercise into our everyday lives?

Seven tenets of neuroplasticity

(Source: The Brain Fitness Program DVD, PBS 2008)

1. Change can occur only when the brain is engaged and in the mood.

Be committed

Pay attention

Be alert, on the ball, ready for action

2. Repetition and change strengthen connections between neurons engaged at the same time.

The brain relates activities to past experience and makes predictions.

When you are working at something and learning, your brain selectively changes the combination of connections that contributed to "the good try."

Stored information rises in our memory successively in time.

3. Neurons that fire together wire together. Neurons that fire apart wire apart.

Repetition strengthens connections between neurons engaged at the same time.

Neurons fire when they are stimulated and become active.

They wire or connect, when they regularly fire together.

When neurons are not activated, or co-activated, those synaptic connections and neuronal networks are weakened, and eventually lost.

4. Initial changes are just temporary.

Things the brain judges to be important are stored in memory.

More lasting memory and brain change occur when you practice and repeat something over and over.

5. Brain plasticity is a two-way street - brain change can be positive or negative.

A brain that is malleable is a brain that is vulnerable.

Addictions and bad habits are based in plasticity.

6. Memory is crucial for learning.

Learning is stored as memory.

When we're engaged in learning something, the brain sets models of where learning is headed.

The brain is remembering from moment to moment how we're progressing toward developing our skill or ability.

It is also evaluating our progress against a model stored in memory.

7. Motivation is a key factor in brain plasticity.

The emotional brain - the limbic system - plays a key role in long-term learning and brain change.

Have a learning goal, but focus on the learning process.

Practice mindfulness and metacognition - remain actively aware of how brain changes occur, as well as proactive in managing the changes to your brain maps.