Our brains on running
What effect does running have on the brain, how good is it for us? Georgia Mills spoke to Henriette van Praag, an Associate Professor of Biomedical Sciences at the Brain Institute at Florida University...
Henriette - Well running has extensive effects on the brain. In humans overall the effects are very beneficial. What we see is that there's benefits for our ability to think, manage time, pay attention, plan. We also see benefits for our ability to remember events, places, people and how they are linked together.
In addition to that we see actual changes in brain structure with exercise. So there is an increase in what we call the grey matter, the part of the brain that contains the neurons, and also white matter which consists of the external pathways that connect cells to each other. And we see also an increase in particular, in the size of the brain area that's very important for learning and memory, called the hippocampus. Incidentally this is the same brain area that is often affected in neurodegenerative conditions such as Alzheimer's disease.
And what happens with exercise is that there is an increase in the volume of the hippocampus and we also see up-regulation of blood flow in that area and in other areas of the brain. And then if we talk about things such as mood or anxiety is that with exercise there's a reduction in anxiety. There's improvement in sleep quality, reduction in stress hormone levels. So these are the kind of the things we know in humans.
Georgia - Why do we think you get these benefits in the brain?
Henriette - With exercise there are neurochemical changes in the brain. So there are changes in neurotransmitters and some of these neurotransmitters are called monoamines and they include dopamine, serotonin norepinephrine, and that family of neurotransmitters is strongly implicated. Exercise up-regulates the level of monoamines. In addition exercise will also up-regulate a protein called Brain-derived Neurotrophic Factor or BDNF.
This is a very important growth factor in the brain which is important for survival, growth of neurons. It influences their complexity, it also influences the ability of neurons to communicate with each other. So it's been shown that if levels of BDNF are low there can be increased anxiety and there can also be learning and memory problems. But other things we can see in terms of measures of anxieties, for example stress hormone levels, such as cortisol in the bloodstream, those also go down with exercise over time and may lead to a reduction in anxiety and depression.
Georgia - But Henriette and her team had an idea. Perhaps not all of these changes were originating inside the brain
Henriette - Not just the brain is running, your whole body is running, you are recruiting you know your heart, bloodstream and of course skeletal muscle. So one of the things that we are very interested in is what is released out of skeletal muscle that might influence brain function.
Georgia - Henriette and isolated muscle cells and treated them with compounds to activate energy pathways, basically engineering exercise in a dish. They took the metabolic soup that came out of the cells, found the compound of interest inside and then added it to brain cells to see what the effect was.
Henriette - You can see an increase in endurance if you give these kind of compounds and you can also see improvement in memory function, suggesting that this kind of pathway of activation may be one of the sources of the effects of exercise on the brain.
Georgia - Right so something that sort of leaks out of our muscles while we exercise makes its way into the brain and we think could be potentially causing some of those benefits?
Henriette - Yes, or at least setting a cascade of events in motion that links to all this plethora of effects that I just described.
Georgia - Does this mean that we could, if we know that factor, could we sort of bottle up exercise and put it in a pill, for maybe those of us who on able to go?
Henriette - Oh no, no, no, no. That would be extremely dangerous! Good try but unfortunately those kind of factors are very tied to our physiology and if you have too much it could be detrimental, too little it’s also not good. That said, it's not completely out of the realm of possible that if we learned more about these factors and know how to potentially modify them, let's say chop off a little bit of the sequences that are potentially involved in detrimental effects, that we could harness them. But then I would probably think only say in cases where you know somebody is incapacitated, cannot walk well, and help to kind of transition back to an active lifestyle. But it would definitely not replace the complete package of the benefits of exercise on our brains, on memory function and on mood.