As we age one thing becomes clear: we just don't function as well as we used to. We lose muscle, coordination, flexibility, and most importantly brain function. As we age the pathways through our brain that control movement, memory, and cognitive function begin to deteriorate. However, much like exercise helps our physical bodies slow the effects of aging, it also helps our brains to retain function as we age, but how?
Exercise increases the concentration of a protein called Brain Derived Neurotropic Factor (BDNF). Neurotropic factors promote nerve cell growth, maturation, and maintenance; BDNF works more specifically in the synapses of these neurons. Synapses are the communication points between nerve cells, and as we age synaptic function declines potentially affecting both muscular contraction and cognition. Synaptic pathways act as the highway system for our nervous impulses, the lanes are the different potential pathways that have been created for learned movements like running, jumping, writing, and speaking. When a synapse no longer sends or receives signals it functions like a roadblock on the highway; one lane goes down but traffic can still move along, though at a slower rate than before. When multiple synapses lose the ability to transmit signals a complete block of the highways becomes possible. When this happens signals can still get to their destinations, however they are forced to use back road routes which take longer and have a higher potential for the signal to get lost. It is the job of the neurotropic factors to create and maintain these highways over the course of a person’s life; BDNF affects neurons in the hippocampus, the cortex, and the basal forebrain which are vital to learning, memory, and higher thinking.
In neurodegenerative diseases (Alzheiemer’s, Parkinsons’s, Huntington’s, etc.) levels of these neurotropic factors are consistently lower. This defecit leads to the common trait amongst these diseases: decreased synaptic communication. However, BDNF production can be stimulated through exercise; which provides an avenue to retrain and maintain some of those lost neural pathways. The brain’s ability to reorganize itself and create new pathways is called neuroplasticity, and BDNF is capable of improving neuroplasticity. A group called Delay the Disease has been treating Parkinson’s patients with BDNF therapy. They accomplish this by having Parkinson’s patients exercise at high intensity for a few minutes, in order to spike their heart rate, and then have the patient perform specific movements, such as getting in and out of a car or handwriting. The patient could also do a complicated multitasking movement with an agility ladder in order to further train Parkinson’s patients brains. Other neurotropic proteins are also being studied as potential treatments for neurodegenerative disease. Finding ways to work around and delay neurodegeneration before it can severely affect an individual’s motor and mental function, would allow us to give them a sense of control over their life that their disease would have taken away.
ging may decrease our physical and functional capacities, but it isn’t the end for progress throughout life. Through proteins like Brain Derived Neurotropic Factor the brain can continue to adapt to the situations presented to it, and even a disease that breaks down our brain’s functional capacity beyond that of aging can be mitigated.