Can muscle strength slow down cellular ageing?
The relationship between muscle weakness and cellular ageing
Some researchers have suggested that muscle weakness is almost as dangerous as smoking. At risk of sounding like a click-bait blog site, here’s what one research actually said…
“Muscle weakness is an important indicator of disability, chronic disease, and early mortality.” (Duchowny et al, 2017)
And here’s what another study said: “sitting has frequently been equated with smoking, with some sources even suggesting that smoking is safer than sitting.” (Vallance et al, 2018)
Oof, that’s pretty bleak huh.
Muscle size, strength and cellular ageing
Scientists set out to find out whether muscle weakness and ageing on a “cellular level” were connected, turns out they are.
Using DNA methylation (DNAm), here’s what they found…
Researchers measured cellular ageing by using 3 biological clocks as a prediction:
DunedinPACE uses a DNA Methylation algorithm to assess a person’s celluar age through blood samples.
Phenoage runs 9 blood tests to establish whether you are older or younger than your actual chronological age.
GrimAge (what a depressing marker name by the way) uses DNAm to predict your health outcome or your life expectancy
Grip strength measurement
It wasn’t exactly feasible to ask every single person involved in the study to test their 1 rep max squat given that the average age of participants was 70 by the time the study was completed, so scientists had to use grip strength as a marker of muscle strength.
The results were pretty compelling….
Participants with a stronger grip were ageing slower on a celluar level than those with a weaker grip.
Now if that’s not bleak enough here’s what they also found…
The Foundation of National Institue of Health (FNIH) categorised 5% of men and 15% of women as “weak” defined by grip strength below 26kg for men and 16kg for women.
It’s important to note here that different institutes categorised their definition of “weak” using different values. The Health and Retirement Study (HRS) for example categorised men with a grip strength below 39kg as below average and placed women who had a grip strength of below 22kg into the same category.
Using this measurement, they placed 55% of men and 45% of women into the “weak category.
In both of the assessments, they found that weaker grip strength was also associated with a slower walking pace and more mobility challenges.
Takeaways
While it’s totally cool to have body goals (most of us do and that is a perfectly valid goal) in order to have a subjectively “nice” physique, you need to build some muscle, and spending the majority of your adult life in a deficit isn’t going to help.
So besides muscle mass actually looking cool (again subjectively), there are clearly many benefits to building more.
For specific information on how to eat and train for muscle gain, check out this blog here where I cover training for size vs training for strength and why they aren’t necessarily the same things.
Resources
Jeff K. Vallance, Paul A. Gardiner, Brigid M. Lynch, Adrijana D’Silva, Terry Boyle, Lorian M. Taylor, Steven T. Johnson, Matthew P. Buman, and Neville Owen, 2018: Evaluating the Evidence on Sitting, Smoking, and Health: Is Sitting Really the New Smoking? American Journal of Public Health 108, 1478_1482, https://doi.org/10.2105/AJPH.2018.304649
Kate A. Duchowny, MPH, Mark D. Peterson, PhD, MS, Philippa J. Clarke, PhD, Cut Points for Clinical Muscle Weakness Among Older Americans. American Journal of Preventative Medicine, 2017DOI:https://doi.org/10.1016/j.amepre.2016.12.022
Dawn E. Alley, Michelle D. Shardell, Katherine W. Peters, Robert R. McLean, Thuy-Tien L. Dam, Anne M. Kenny, Maren S. Fragala, Tamara B. Harris, Douglas P. Kiel, Jack M. Guralnik, Luigi Ferrucci, Stephen B. Kritchevsky, Stephanie A. Studenski, Maria T. Vassileva, Peggy M. Cawthon, Grip Strength Cutpoints for the Identification of Clinically Relevant Weakness, The Journals of Gerontology: Series A, Volume 69, Issue 5, May 2014, Pages 559–566, https://doi.org/10.1093/gerona/glu011
