Is exercise really that good for our brain? Research suggests that exercise will enhance our brain activity and increase our memory capacity. We’ve all seen the headlines – “Boost your Brain Power with exercise!” and “Exercise Protects Brain from Ageing!”. Yet getting on this bandwagon seems to be difficult for most people. We are taught to question everything from a young age and that we have. How much exercise is too much? Which types of exercise are good for our brains? Can it really help stave off dementia? Exercise and diet companies are generally some of the highest profit grossing businesses in the western world. While there is a large body of evidence out there to suggest it does aid in improving our cognitive abilities (i.e. brain power) the following study suggests there may be more at play than simple exercise routines when it comes to keeping our brains “fit”.
In a study by Wagner et al., (2017) they set out to determine if participating in an intense exercise program for a short duration can actually improve the size of our hippocampus (the part of our brain involved with memory). The hippocampus is known to decrease in size with age and this group of researchers suggested that this high intensity exercise program will increase the size. They measured the size based on fMRI scans and also by using what are called brain-derived neurotrophic factors or BDNF for short. These biomolecules are mainly made up of proteins which are involved in helping to grow new neurons (brain cells). They wanted to test whether “exercise induced brain-derived neurotrophic factors” could account for increases in hippocampal activation. Recent studies show just how “plastic” our brains can be. This involves changing over time due to our environment or different contexts. The idea is exciting for many researchers and scientists alike because it suggests we actually DO have control over our bodily and mental functions as it was once thought the brain developed to a certain degree and then stopped and went on a steady decline until death. Not so uplifting.
The researchers recruited a group of 34 healthy male participants who were assigned to either an experimental group (EG) or a control group (CG). Seventeen of the participants in the experimental group were assigned based on age, gender, body mass index (BMI), and their amount of oxygen intake. The remaining seventeen participants were assigned to the control group where they did not partake in the exercise program. The program consisted of one week of pre-testing, to determine their physical abilities, followed by 6 weeks of intense physical activity using a test stationary bike. Brain scans were completed, and blood was taken prior to the program and again after the program. They used the blood samples to measure the difference in the amount of BDNF’s to determine if there was an increase in these neuron enhancing/stabilizing proteins. They also used a verbal-learning and memory task, and paired-associates task after the EG completed the program. This task is widely used to assess the subjects verbal and learning as well as memory functions. They even factored in a practice effect and used two forms of the VLMT test, one pre-experiment and one post. The researchers even controlled for dehydration effects when looking at brain scans by having a 24-hr grace period after the exercise programs were completed to conduct the fMRI’s. With all of these factors taken into consideration one would assume this was a sound study and would have some significant results. While a few of the findings were significant such as “a significant exercise-induced increase was observed in the left anterior hippocampus, in the right thalamus, in the posterior (PCC) and anterior cingulate cortex (ACC), in the pre- frontal regions as well as in the temporal cortex”, (basically an increase all over the brain). However, the study did not find any increase in the BDNF in the blood samples taken before and after and actually found a decrease in the experimental group.
Wagner at al. (2017) did point out that their sample size was relatively small and they also didn’t take into account the fact that the entire group of participants were healthy fit males. So, do we discount the fact that exercise is good for our brains based on this study? Absolutely not. This just adds to the growing body of evidence which will help us one day to determine the exact effects exercise has on our brains.
Wagner, G., Herbsleb, M., de la Cruz, F., Schumann, A., Köhler, S., Puta, C., Gabriel, H., Reichenbach, J.R., Bar, K., (2017). Changes in fMRI activation in anterior hippocampus and motor cortex during memory retrieval after an intense exercise intervention. Biological Psychology, 124. 65-78. http://doi.org/10.1016/j.biopsycho.2017.01.003.
