According to the Centers for Disease Control and Prevention, falls are the leading cause of injury for adults aged 65 and older in the United States every year. These falls often lead to injuries that can be debilitating and even fatal.
Researchers have long known that these injuries are preventable, but new research out of Syracuse University looks at ways to combat nerve deterioration — instead of bone and muscle loss — that puts seniors at risk of injuries from falls and other accidents.
Postdoctoral researcher JoCarol Shields and exercise science professor Jason DeFreitas believe simple resistance training could be the answer.
According to a press release from Syracuse University, the nerves that control our muscles naturally degrade and become slower as we age. This is called denervation.
“For people in their 70s and 80s, it’s about preserving what you have,” Shields, who is working in the Neural Health Research Laboratory, said. “The aging process is going to happen no matter what, but can we slow it down.”
Denervation is especially problematic in people who are sedentary, meaning even just integrating some simple exercise can help seniors maintain their independence and quality of life longer.
To study this, the researchers charted the effects of resistance training on nerve conduction velocity, a measure of how quickly electrical signals travel along a nerve.
With 48 subjects ranging from 18 to 84 years old, the researchers recorded NCV in the forearm, as well as each subject’s maximal strength, or the greatest amount of force a muscle can generate in a single contraction.
They tested these metrics before and after four weeks of handgrip resistance training in both arms.
The results? Every senior showed improvement in their nerve conduction after four weeks of resistance training.
This is a significant finding, especially for the implications of denervation.
As the researchers explain, a nerve contains both fast and slow motor neurons, with the fast neurons being the first to deteriorate. This typically manifests as the nerve disconnecting from the muscle and becoming inactive with age.
“When you lose fast neurons, you also lose the fast muscle fibers that are activated by them, and then your power, or the speed at which you can produce force, decreases,” DeFreitas explained.
They hypothesized that the training helped reactivate these fast neurons in older participants.
“If you can reactivate those lost neurons, you can produce force faster again, and that has practical implications so that a slip or a trip doesn’t become a terrible fall,” he added.
The researchers’ work was published in the journal “Medicine & Science in Sports & Exercise” earlier this month. The journal’s editor-in-chief, Andrew Jones, praised their findings.
“Research on the adaptations to resistance training has historically been focused on muscle and bone, with very little known regarding the adaptability of the nerves,” Jones wrote.
“Because nerve health and function deteriorate with both age and prolonged sedentary lifestyles, it is important to know if resistance training is an effective countermeasure to combat this degradation.”
He went on to add that the research shows that nerve function in older adults is trainable and could hold further implications for nerve health, motor function, independence, and quality of life.
“This work could stimulate investigations into whether resistance training is an effective countermeasure for other, non-age related sources of nerve degradation (for example, nervous system disorders),” he added.
The researchers hope to conduct additional studies to determine the role that exercise may play in mitigating age-related nerve deterioration, and if the reactivation of fast neurons can be translated to other parts of the body (this study only documented nerves in the arms).
“If we’re reactivating those neurons that started to die, that can play a significant role in the preservation of strength and avoiding disability with aging,” DeFreitas said.
“That to me is the likely hypothesis, so that’s the premise of the follow-up work we’re conducting.”
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