I was struck last week by a widely reported new health study1 out of Brazil that found a strong correlation between all-cause mortality (epidemiology’s fancy term for the general death rate) and just one physical test: the subject’s ability to balance on one leg for 10 seconds.
Over 12 years, 1702 people, adjusting for age, sex, etc., that test showed it could be used to predict positive and negative health outcomes.
Conclusions Within the limitations of uncontrolled variables such as recent history of falls and physical activity, the ability to successfully complete the 10-s one-legged stance is independently associated with all-cause mortality and adds relevant prognostic information beyond age, sex and several other anthropometric and clinical variables.
So what’s the takeaway for us non-Brazilians? It can’t just be Samba or die.
In fact that’s not too far off. But let’s back up a bit.
Muscles and Masters Athletes. Around the time I started my Ironman journey a study2 titled “Chronic exercise preserves lean muscle mass in masters athletes” was doing the rounds, mostly because of this set of images showing the MRI scans of different subjects’ quadriceps:
I’ll let you make your own conclusions about these, but for me it told me a lot about the different ways you can fill out a set of clothes. By relying on how my clothes fit I could be a wide range of fitness and fatness levels. Measuring body composition through techniques like pinch tests, calipers, bioelectric tools, and dexa scans are the effective ways to see which of those pictures we are closer to. We can lose muscle mass and gain fat and still fit in the same clothes, still kind of look the same to someone walking by.
What I missed (because I didn’t get past the pictures) is how the science had shown that it was simple to remain strong and have good musculature even late in life when most think of muscle loss as part of our inevitable decline with age.
Here are the authors’ conclusions:
The loss of lean muscle mass and the resulting subjective and objective weakness experienced with sedentary aging imposes significant but modifiable personal, societal, and economic burdens … This study, and those reviewed here, document the possibility to maintain muscle mass and strength across the ages via simple lifestyle changes.
Grip Strength. Several years ago I learned about another biomarker for longevity similar to the one-legged balance test: grip strength. Subjects are asked to squeeze a dynamometer several times with each hand to get an average measurement over both hands. What is wild about this measurement is that it can be used for more than just predicting all-cause mortality. It has been widely studied. Just look at the conclusions of this review3.
Based on the review it appears that there is adequate evidence to support the use of grip strength as an explanatory or predictive biomarker of specific outcomes such as generalized strength and function, bone mineral density, fractures, and falls, nutritional status, disease status and comorbidity load, cognition, depression, and sleep, hospital-related variables, and mortality.
Yeah, even cognition and depression.
That said, it’s important to remember that this is a biomarker, not a solution. This quote4 is useful:
“Just improving grip strength will not improve your overall health,” Gray says.
Cathleen Colon-Emeric, head of the geriatrics division and associate dean for research mentoring at Duke University School of Medicine, says that “We should consider grip strength as an overall biomarker of health, and improving it by itself will not lead to improved outcomes.”
“Instead, we should focus on maintaining or improving muscle mass, which greatly reduces the risk for many conditions,” she says.
The Centenarian Olympics. More recently I’ve been listening to Dr. Peter Attia on multiple different podcasts. He introduced the idea of a “Centenarian Olympics”, where he asked himself what needed to happen for the rest of his life to not just reach 100 years old but be able to perform certain physical tasks at that age. The main one was to be “able to drop into a squat position and pick up a child that weighs 30 pounds”. His thinking was that he’d like to be able to lift up his great grandkids and play with them.
You’ll note that to be able to perform that task you would probably need to score well on the tests performed in the 3 papers mentioned above: good balance, good grip, and a strong musculature.
Dr. Attia comments that our time spent sitting causes us to lose much of our stability and our ability to use our core muscles in lifting movements. It’s fascinating stuff and well worth reading or listening to.
Use your damn muscles. We can’t just eat healthy foods and reach the finish line: we’ll fall over and break a hip before we get there. Nor can we only focus on aerobic exercise. All those Blue Zones everyone studies - a Strong99 essay for another day - show that people in those communities are physically active doing chores throughout every day of their lives. It seems overly simplistic to say that we need muscle mass to support us but it is very much the truth. We maintain or build muscles by using them, and we can do it throughout our “age-related decline”.
I can attest to the fact that watching Netflix from the couch causes muscle atrophy: watching people samba is not the same as actual dancing.
Araujo CG, de Souza e Silva CG, Laukkanen JA, et al, ‘Successful 10-second one-legged stance performance predicts survival in middle-aged and older individuals’, British Journal of Sports Medicine Published Online First: 21 June 2022. doi: 10.1136/bjsports-2021-105360
Andrew P. Wroblewski, Francesca Amati, Mark A. Smiley, Bret Goodpaster & Vonda Wright (2011), "‘Chronic Exercise Preserves Lean Muscle Mass in Masters Athletes’, The Physician and Sportsmedicine, 39:3, 172-178, DOI: 10.3810/psm.2011.09.1933
Bohannon RW., ‘Grip Strength: An Indispensable Biomarker For Older Adults’, Clin Interv Aging. 2019 Oct 1;14:1681-1691. doi: 10.2147/CIA.S194543. PMID: 31631989; PMCID: PMC6778477.
Amanda Loudin, June 15, 2019, ‘What your grip says about your odds of surviving a health crisis’, The Washington Post, https://www.washingtonpost.com/health/what-your-grip-says-about-your-odds-of-surviving-a-health-crisis/2019/06/14/76eff7b2-77f0-11e9-bd25-c989555e7766_story.html