With an aging population now a reality in many Western nations, how well we age is becoming as much of a focus as longevity itself. A new study emerging from the Manchester Metropolitan University, published in the Journal of Physiology, is throwing new light on this topic and it is news that nervous system and health enthusiasts will welcome. It appears that the muscle loss many have accepted as “inevitable” in old age is actually a nerve issue.
The study took 143 men, aged either 18-40 or 65-90 years old and living independently, and used MRI and EMG data to view the state of their muscles.. They were looking at generally healthy young and older men to examine age-related loss of muscle, and low muscle mass known as sarcopenia.
One of the study’s authors, Professor Jamie McPhee, stated that “There was a dramatic loss of nerves controlling the muscles – a 30-50% loss – which means they waste away. The muscles need to receive a proper signal from the nervous system to tell them to contract, so we can move around [1].” While the first part of that remark wouldn’t surprise anyone in health-related fields, the second part (which indicates the role of the nervous system) is a laden with possibilities for nervous system and health related fields.
While this research did offer up some good news in that healthy muscles can send out new branches from surviving nerves to “rescue” muscles and stop them wasting away, it is more likely to happen in fit people with large, healthy muscles [1].
The study found that “the age-related loss of muscle mass is related to the loss of innervating motor neurons and denervation of muscle fibres [2].” However, this didn’t necessarily mean that all muscle fibres were degraded. “Some may be reinnervated by an adjacent surviving neuron, which expands the innervating motor unit proportional to the number of fibres rescued,” the study stated [2]. “These findings suggest that healthy older men reinnervate large numbers of muscle fibres to compensate for declining motor neuron numbers, but a failure to do so contributes to muscle loss in sarcopenic men.”
It is a generally accepted ‘fact’ that people become weaker in their later years (in most cases), often leading to disability and falls [3]. This study shows that general health and muscle mass in younger years matters greatly when it comes to maintaining muscle mass in older adulthood. It also shows the vital role of the nervous system in maintaining muscle mass over time.
It’s a study that builds on earlier, more muscle-group specific data. One of the study’s lead authors, Dr Mathew Piasecki, remarked [3]:
“One of the earliest attempts at research similar to ours showed results from a small group of older people who apparently had just a couple of surviving nerves feeding into a foot muscle.
“We were very sceptical of the old data, however, now that we have tested a couple of hundred men we think the early observation was probably correct. We have also observed some very old muscles with just a few dozen nerves left, where young and healthy adults have hundreds.”
What next?
Manchester Metropolitan University has indicated that researchers are currently looking at “whether regular exercise in middle and older-age slows the process of muscles becoming disconnected from the nervous system, or improves the success of nerve branching to rescue detached muscle fibres.” They further stated that “the goal is to identify the best type of exercise – strength training or endurance – and to understand the physiology of why the nerve-muscle changes occur as we get older [4].”
Obviously this research did not look at the impact chiropractic care could have on muscle mass. However, we do have research indicating the impact of chiropractic care on the brains ability to drive the muscles [5,6,7, 8]. As time and research marches on, we are seeing more and more evidence to back this up. We hope that in time, chiropractic research will reveal the impact of subluxation-based care on maintaining muscle mass, as well as other impacts it could have on healthy aging.
All in all, research that indicates a nervous-system role in maintaining muscle mass is good news for chiropractors indeed.
References
[1] Staff Writer, 2018, “Muscle loss in old age linked to fewer nerve signals”, BBC Online, https://www.bbc.com/news/health-43347409 retrieved 7 June 2018
[2] Piasecki M, Ireland A, Piasecki J, Stashuk D, Swiecicka A, Rutter M, Jones, D and Mcphee J (2018), “Failure to expand the motor unit size to compensate for declining motor unit numbers distinguishes sarcopenic from non-sarcopenic older men,” The Journal of Physiology, https://doi.org/10.113/JP275520 retrieved 7 June 2018
[3] Knapton S, 2018, “Inevitable wasting of muscle in old age could be stopped scientists believe,” The Telegraph, https://www.telegraph.co.uk/science/2018/03/12/inevitable-muscle-wasting-old-age-could-stopped-scientists-believe/ retrieved 7 June 2018
[4] Staff Writer, 2018, “Old age muscle loss linked to drop in nerve signals,” Manchester Metropolitan University, https://www2.mmu.ac.uk/news-and-events/news/story/7387/ retrieved 7 June 2018
[5] Haavik H, Ozyurt M, Niazi I, Holt K, Nedergaard R, Yilmaz G, Turker K (2018), “Chiropractic Manipulation Increases Maximal Bite Force in Healthy Individuals,” Brian Sciences, 2018, 8, 76; doi:10.3390/brainsci8050076
[6] Haavik, H.; Niazi, I.K.; Jochumsen, M.; Sherwin, D.; Flavel, S.; Türker, K.S. Impact of spinal manipulation on cortical drive to upper and lower limb muscles. Brain Sci. 2017, 7, 2
[7] Christiansen, T.; Niazi, I.; Holt, K.; Nederggard, R.; Duehr, J.; Schlupp, V.; Marshal, P.; Türker, K.S.; Hartvigsen, J.; Haavik, H. The effects of a single session of spinal manipulation on strength and cortical drive in athletes
[8] Niazi, I.; Türker, K.S.; Flavel, S.; Kinget, M.; Duehr, J.; Haavik, H. Changes in h-reflex and v waves following spinal manipulation Exp. Brain Res. 2015, 233, 1165–1173.
