So, to answer last week’s question, what are the reasons that exercise is such a powerful tool, and how does it work? There are four main reasons that make it such a powerful tool:
- Serotonin (a neurotransmitter which regulates our mood)
- BDNF (a protein belonging to the family of growth factors)
- Dopamine (a neurotransmitter responsible for the sensation of pleasure)
- Endorphins (a neurotransmitters in the brain that alleviates both physical and mental pain)
Exercise increases the rate and frequency at which serotonin is “fired” within the brain, resulting in an increase in both the release and synthesis of it. Secondly, regular exercise increases the level of tryptophan in the brain (an amino acid used to manufacture serotonin). The exact mechanism is not clearly understood; however, it is clear that aerobic exercise improves mood through increasing brain serotonin levels.
Apart from its obvious health benefits and its mood enhancing capabilities exercise plays a significant role in the process of neurogenesis (the creation of new brain cells). BDNF is responsible for neurogenesis in the hippocampus, which we know from previous posts is responsible for: learning and memory. The exact mechanism behind neurogenesis is still not completely understood but it is believed that the mild stress generated by exercise stimulates the creation of BDNF proteins that act to promote neurogenesis. BDNF acts not only to generate new neurons, but also to protect existing neurons and to promote neuroplasticity. This is particularly relevant because the brain starts to lose nerve tissue beginning at age 30. Aerobic exercise reinforces neural connections by increasing the number of dendrite connections between neurons, creating a denser network, which is then better able to process and store information. This suggests possible preventative and therapeutic effects for diseases such as Alzheimer’s and Parkinson’s that progress via the loss of neurons. In addition, exercise has been shown to decrease the loss of dopamine-containing neurons in mice with Parkinson’s.
It has also been shown that physically active people recover from mild depression more quickly, and physical activity is strongly correlated with good mental health as people age. Depression is related to low levels of certain neurotransmitters like serotonin and norepinephrine. Exercise increases concentrations of these neurotransmitters. In addition, serotonin has a reciprocal relationship with BDNF, i.e. BDNF boosts serotonin production and serotonergic signaling stimulates BDNF expression. Since exercise also increases BDNF production directly, there is a reinforcement of the serotonin-BDNF loop, indicating exercise’s significant potential as a mood-enhancer.
Finally, exercise produces the release of Endorphins which interfere with the transmission of pain impulses to the brain. Thus, endorphins tend to minimize the discomfort of exercise and are even associated with a feeling of euphoria.
So, to sum up exercising (in particular aerobic exercise) is much more beneficial to us than simply getting into good shape. We know that exercise can be used as a preventative tool against Alzheimer’s, to increase memory capabilities, and reduce anxiety and depression. In fact, recent research demonstrates that regular exercise over a 4 week period is almost as effective as antidepressants.
However, individuals often struggle to maintain an aerobic exercise regime, such as jogging. The trick is to gradually work your way up to at least 30 minutes of continuous aerobic exercise because the release of endorphins usually takes about 30 minutes from the start of continuous moderate activity (65 percent of your maximum heartrate, which is 220 minus your age)
Hope you enjoyed this four part series on neurogenesis and that you’ll be motivated to take advantage of all the benefits exercise has to offer!
Until next week, Stay tuned!