Exercise, specifically cardiovascular and strength training, can improve your heart, lungs, muscles, bones, peripheral nervous and other systems in your body.
But how much effect does it have on the brain?
As we age, the normal activities of living that many of us take for granted can become more difficult. With dementia, as the structure of brain tissue degenerates and shrinks, the function also becomes impaired. Not only does the motor ability to retain balance and coordination decrease, but the ability to think, remember, plan, decide, perceive, reason and learn all can become progressively impaired.
It is predicted that by the year 2050, 135 million people will be affected by dementia. It is therefore important that we do all we can to try to limit the effects of dementia, including the erosion of cognitive abilities, known as executive function’, as much as possible.
In the 1990s, researchers in California first discovered that exercise can have a positive effect on the brain. In these important experiments, the mice that ran produced far more cells in an area of the brain that is involved with memory function than mice that didn’t run. The exercised animals then performed better on memory tests than their sedentary counter-parts, which showed that a change in structure caused a change in function.
These studies were replicated in 2012, but added a resistance training component. In this study, the weight trainers produced higher levels of one particular brain protein (insulin-like growth factor), which initiates cell growth and maintenance, and the runners’ brains displayed higher levels of another protein (BDNF, or brain-derived neurotrophic factor), which helps grow new brain cells and nourish existing ones. Having more of either protein is desirable for brain health, so it would appear that performing both aerobic and resistance exercise would create more of both substances.
There have been many human studies just in the past decade, and some of the most recent have focused on resistance training in particular. A 24-week study was published in 2007 and showed an improvement in cognition in 62 sedentary men between 65 and 75 years old who performed high and moderate intensity resistance training. The resulting increase in mental ability was hypothesized to come from the increase in the same insulin-like growth factor (IGF-1).
Another six month study done at UBC in 2012, involving 86 women with mild cognitive impairment, ranging in age from 70 to 80 years old, split the group into weight training, aerobic walking and balance groups. Despite positive changes in brain function (memory, problem solving, and attention) from all groups, the one that had the most impact was the strength training group.
The researchers posit that this may be due to deeper, more diverse brain involvement with the higher levels of intensity and effort that come with strength training.
Researchers still don’t know the exact mechanisms by which exercise helps brain structure and function, but exercise, and in particular strength training, is showing positive effects in delaying the onset of dementia in those with mild cognitive impairment.
