YOUR BRAIN ON EXERCISE
One of our favourite books at Lift and a highly recommended read is Brain Rules by John Medina. Dr Medina is a developmental molecular biologist focused on the genes involved in human brain development, and his book outlines the seven rules of boosting brain health as shown by scientific research. Unsurprisingly at Rule #1: “Exercise boosts brain power!”
There are many mechanisms through which exercise improves the health of the brain, and there are many areas of cognitive function that are improved by exercise. Scientists categorise some of these brain functions with names such as “executive function”, “visuo-spatial function” and “reaction speed”.
UPGRADE YOUR PROCESSING POWER!
The long and short of it is that exercise shows huge improvements in every aspect of brain function, including things that might be called in layman’s terms as processing speed, problem solving, planning, memory recall, spatial awareness and protection against disease such as Alzheimer’s. In other words, every aspect of your life is affected, because the brain is the portal through which we interpret and interact with the world around us.
YOU’RE ONLY AS OLD AS YOU THINK
There’s no age limit to this either! Studies have been conducted on young and old alike that show a direct effect of exercise on brain performance. Meta-analyses (the gold standard of scientific research that examines all the applicable studies in a particular area) of brain function on older populations have shown the marked improvements in all the areas mentioned above, but as Dr Medina points out in Brain Rules, young people benefit too: “Among 27 year-olds, a 12-week exercise program was begun. Brain function rose. Exercise was stopped. Brain function fell.”
Just check out the graph!
GETTING DOWN TO IT: HOW EXERCISE WORKS FOR BRAIN POWER
There are two main reasons for this improvement in brain health, each of which have a variety of mechanisms behind them.
Firstly, exercise increases the flow of oxygen through the brain. There is an interesting association in the scientific literature between oxygen saturation in the brain and mental quickness. This is mainly mediated by a reduction in free radicals in brain tissues
Secondly, exercise literally changes the structure of brain tissue. It has been shown to increase the genesis of neurons, to improve their resistance to stress and disease and also to create and maintain structural links between those neurons.
GAINS FOR BRAINS?
While most studies have looked at the benefits of aerobic training on brain health, some have examined the effects of a varied exercise regime. One study in particular found that performing a highly familiar and repetitive task such as cycling or running at a moderate intensity produced more alpha-wave activity in the brain – this is associated with a relaxed but alert state.
Interestingly, however, more complex tasks or those requiring higher levels of force production require greater signalling from the neural cortex in order to accurately respond to a dynamic and varied set of demands on the body. Then there are the hormonal implications of training.
ALL IN YOUR HEAD
In his book Spark, Dr John Ratey MD describes how “exercise unleashes a cascade of neurochemicals and growth factors that physically bolster the brain’s infrastructure”.
Exercise increases levels of neurotransmitters involved in the formation of thoughts and emotions such as serotonin, norepinephrine, and dopamine. Dr Ratey prescribes exercise as a treatment for mental illnesses such as depression and anxiety for this very reason.
For example, one study done on rats showed that exercise-induced elevation of IGF-1, a hormone produced in high amounts by more strenuous training modalities, increases neuron survival and plasticity (ability to adapt and change in response to demands on the brain). IGF-1 elevations are best produced by training that requires a high level of force production from the working muscles, such as moderate to heavy resistance training.
Another recent study found that endurance exercise leads to release of a hormone called irisin that promotes the development of new nerves and synapses.
PROGRAM YOUR BRAIN
Interestingly, correctly programmed high intensity exercise leads to similar aerobic adaptations in shorter durations of exercise – meaning that you can still reap the same benefits of aerobic training whilst improving strength, preserving lean body tissues such as muscle and challenging the brain with greater variety of movements.
Whilst aerobic adaptations are also important, long-duration exercise can increase levels of the stress hormone cortisol, which has negative implications for brain health when chronically elevated.
Therefore, it is advisable to include training of varied modalities to optimise brain function by challenging neurological systems, activating different brain pathways such as those responsible for spatial awareness or muscular motor unit recruitment, and producing an optimal hormonal response to encourage neuron growth and reduce inflammatory chemicals in the brain.
Chang, H., Yang, Y., et al. IGF-1 Signaling for Brain Recovery and Exercise Ability in Brain Ischemic Rats. Medicine and Science in Sports and Exercise. May 2011.
Colcombe, S and Kramer, AF (2003) Fitness effects on the cognitive function of older adults: a meta-analytic study Psych Sci 14: 125 – 130
Harada, T. et al (2004) Jogging improved performance of a behavioral branching task: implications for prefrontal activation Neuroscience Research 49: 325 – 337
Nagamatsu, L., et al. Physical activity improves verbal and spatial memory in older adults with probable mild cognitive impairment: a 6-month randomized controlled trial. Journal of Aging Research. 2013. 2013, 861893.
Meckel, Y., Nemet, D., Bar-Sela, S., Radom-Aizik, S. Hormonal and Inflammatory Responses to Different Types of Sprint Interval Training. Journal of Strength and Conditioning Research. 2011. 25(8), 2161-2169.
Medina, John. (2009). Brain Rules: Pears Press.
Ratey, John. (2013). Spark: Little, Brown and Company.
Tanner, A., Nielsen, B., et al. Salivary Steroid Hormone Response in Trained Men to Running and Circuit Training Sessions. British Journal of Sports Medicine. December 2011. 45(15), A6.