Recently, many researchers have been focusing on the effects of exercise on both physical and mental health. Unfortunately, much of the developed world is plagued by obesity and many people do not exercise as much as they should. Many people realize that exercise is crucial for maintaining a healthy BMI, but what most people do not realize is that exercise affects the brain in such a way that memory and even mental health can be improved.
A study recently published in Biology of Sport indicates that exercise can initiate neurogenesis in the subventricular zone of rats. The function of the subventricular zone has not been studied extensively in humans, but in rats, it is a major source of neural stem cells used in adult neurogenesis. Rats were divided into a control group and an exercise group (5 days of swimming exercise, for 8 weeks). Afterwards, the researchers measured neurogenesis in the subventricular zone, and levels of nerve growth factor and synapsin (a protein involved in neurotransmitter release), in the olfactory bulb. After analyzing the brains of the rats, they found that the swimming exercise group had significantly higher neurogenesis in the SVZ than the control group.
Because neurogenesis is expected to play a role in psychiatric illnesses, including depression, anxiety, and schizophrenia, the results indicate that exercise is more important for mental health than previously believed. What I am curious about is if the exercise itself is the only factor in increasing neurogenesis. Stress and disrupted sleep are also known to decrease neurogenesis, and affect not only a person’s happiness but their cognitive functioning as well. Many people exercise to reduce their stress, so could the increase in neurogenesis due to exercise be due to multiple factors?
A study done by Koehl et al. (2008) found that the endorphins released during exercise can also increase cell proliferation in vitro. This indicates that the endorphins released during exercise either have multiple effects, or that the cell proliferation that they cause is helping to contribute to the elevated mood that exercise is known to cause. Because neurogenesis is a highly researched topic and is thought to be involved in many neurological and psychological disorders, I expect that there will be much more research on its connection to health in the near future.
Chae, C., Jung, S., An, S., Park, B., Kim, T., Wang, S., … Kim, H. (2014). Swimming exercise stimulates neurogenesis in the subventricular zone via increase in synapsin I and nerve growth factor levels. Biology of Sport, 31(4), 309-314.
Koehl, M., Meerlo, P., Gonzales, D., Rontal, A., Turek, F., & Abrous, D. (2008). Exercise-induced promotion of hippocampal cell proliferation requires beta-endorphin. The Journal of the Federation of American Societies for Experimental Biology, 22(7), 2253-2262.