Although the link between exercise and heart health is well-known, researchers are only now starting to piece together what happens to our most complex organ - the brain - when we work up a sweat. For nearly a century, scientists have been exploring how physical activity affects brain function ,but it wasn’t until the 1970s that researchers were able to prove a strong link. It all started with psychomotor functioning, which controls how quickly we react to a situation. Through a series of studies, scientists started noticing that older people who take up regular exercise had improved hand-eye coordination and performed better on reaction-time tests over their sedentary counterparts. Then the tech boom came along: neuroimaging techniques such as MRI tests bridged the gap between human and animal studies, and researchers finally got a closer glimpse at the mechanisms at play. The idea that we could physically train to improve not only our bodies, but also our brain function, at any age, started to gain momentum.
So what is it about exercise that affects our brain at the cellular level? This is where neuroplasticity comes in. The brain has the incredible ability to grow, change and develop based on our environment and experiences, and it’s this changing structure of the brain — its plasticity —that has allowed humans to survive for thousands of years.Professor Anthony Hannan, head of the Neural PlasticityLaboratory at The FloreyInstitute of Neuroscience andMental Health in Melbourne, says that physical activity has the ability to strengthen the connection between neurons, which help transmit messages around our mind and body.“Physical activity is good for every organ in your body. Your Brain doesn’t sit up there in your skull in an ivory tower; it's in constant bi-directional talk across your body with all the other systems,” he explains.“Exercise boosts neurogenesis, which is the birth of new neurons in the adult brain…it can also impact on synaptic plasticity, which is basically the use it or lose it’ concept. ”Most changes occur overtime, and research shows individuals who are active often and for longer periods, usually with cardio, tend to perform better in brain tests. A decade ago, Professor Hannan and his team at The Florey were the first to show that long-term voluntary activity, where mice could freely exercise on the wheel at any time, reduced the late onset ofHuntington’s disease — which is an inherited neurological condition that causes damage to the brain.They were also able to show that regular exercise reduces depression — the most common psychiatric symptom of Huntington’s disease. There’s also an immediate effect from physical activity on the brain. In one 2014 study involving 25 healthy adults who rode on stationary bikes at different intensities for varying durations, researchers found even a single bout of aerobic exercise can promote neuroplasticity. They discovered that simply cycling at low-intensity for 30 minutes encouraged short-term rewiring and neuroplasticity in the brain, with the effect seen right through to the region that controls hand muscles, even though cycling only involves the legs.
Epigenetics — the study of how the environment can influence our genes — provides further insight. ProfessorHannan elaborates: “We’re all dealt a deck of ‘genetic cards’ at conception and you have them your whole life.While the environment can't change the letters of DNA, the sequence, itcan change which genes are turned on and off in particular cells throughout your lifetime.”Combining physical activity with our unique genetic code is one way of controlling our risk of developing specific diseases such as Alzheimer’s, dementia and other age-related brain disorders, according toProfessor Hannan. With such promising results, it’s no wonder the international medical community has re-focused its attention to harnessing the power of exercise to keep the brain healthy and strong. Here are some other science-backed ways proving the benefits of exercise on our body and mind.
Regular Exercise boosts memory, improves cognitive performance and physically expands the brain to make room for new connections between neurons. One of the largest longitudinal studies to prove this was the CARDIA study, which found that individuals who maintained higher levels of cardiorespiratory fitness between their mid 20s and early 50s scored higher on the verbal memory and psychomotor tests, compared to the lower level fitness groups.
The amino acid glutamate is responsible for sending signals between the cells in our brain. But in some people, especially those withMND/ALS, epilepsy or Huntington's Disease, glutamate is overproduced, causing blockages that may lead to toxicity in the brain. A 2016 study published in Applied Physiology,Nutrition, and Metabolism found that exercise directs glutamate into “spring clean” mode by sweeping out excess amounts of the amino acid, in turn reducing the severity of the disease.
Physical activity boosts the neurotransmitter pathways in our brains, which helps to regulate our emotional health. Regular physical activity, including simply walking or cycling instead of driving and taking the stairs at work, can contribute to brain health. Physical activity may reduce the negative effects of chronic stress and have an antidepressant effect.
Everyone’s at risk of the effects of ageing and the associated decline in cognitive function, but the two don’t have to go hand-in-hand.People who regularly exercise in earlier life, and continue doing so in older age, possess higher memory retention, and are at reduced risk of Alzheimer's Disease and other forms of dementia.