The Truth About Losing Muscle With Age

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From the time we’re born until somewhere around our 30’s, our muscles grow larger and stronger. I’ve written about it before… it’s our whole “growth” phase, when our bodies are pretty forgiving and can still radiate health even if we don’t exercise. And then we turn 40 (or so) and suddenly things start to change. Our default fades from “growth” to “deterioration”, and without exercise, our muscles begin to get smaller and weaker.  It’s called age-related sarcopenia.

All of that’s well-known and accepted. Problem is, too many people are misinterpreting it. It’s become all too common to jump to the conclusion that we will inevitably lose our muscle mass and our strength with age. We’re all wasting away, apparently, so just accept it. No, people. Just no.



This picture is from one of my most favorite studies of this decade.  It was significant back when it was published in ‘The Physician and Sportsmedicine‘ journal in 2011 because at the time, it seemed every other related study was measuring natural muscle loss on the general population, but this one contradicted all that by showing that age-related sarcopenia IS NOT INEVITABLE. Its effects can be held at bay with exercise, as evidenced by this remarkable MRI comparison photo. Just look at those big beautiful meaty quadriceps on the 70-yr old athlete. And how about his bone diameter! Compare that to sedentary man’s thin bone, minuscule muscle, and even more adipose tissue density within the muscle mass itself… and, well I just want to get up and do some squats right now.

So here’s the hard truth about our aging muscles:

The amount of muscle you’ll lose as you age is due to your activity levels. As long as you’re an otherwise healthy adult, it’s your choices that will decide which of these MRI scans more closely resembles you. Let’s stop accepting that muscle wasting is our natural aging process, because at least up until the very end stage, it isn’t. Our modern culture’s sedentary way of life is more to blame for muscle loss, not aging.

But hey, there’s a bright light here, even if you’re currently not exercising. Because even if you’ve made some bad choices up till now, your body is remarkably adaptable. It WILL work with you and respond favorably to new exercise habits!

Now, I’m not saying for older folks it’s as EASY to build and maintain muscle as it is for younger people. Youth have their “growth default mode” advantage. Think of it like training at high altitude and then having the advantage at a sea level race, while us older folks don’t have the sea level advantage. It can be done, we just have to work harder, consistently, and be much smarter about our advanced-years training.

Okay, all that said, let’s move on to a new (but related) topic.

Get a load of this:

This comes from a study published by the American College of Sports Medicine, and it’s showing the number of functional motor units in the arm muscles of nine young runners (the ‘Y’) with an average age of 27, nine old runners (the “O”) with an average age of 70, and nine lifelong masters runners (the “MR”) with an average age of 70. Take note these people are RUNNERS. They’re using their legs to perform their activity, not their arms.  As you can see, the older folks have significantly less motor units in their arm muscles (so, less muscle mass and less strength) than the young runners… proof of the age-related sarcopenia process at play here.

What this shows is that just the act of exercising doesn’t give us some sort of “whole body neuroprotection.” Exercise only preserves the muscles you’re using. I know, this isn’t mind-blowing or anything and seems common sense. But yet culturally, we sort of know this and ignore it. Runners continue to just run, cyclists just bike, and the walkers seem to think they’ve got fitness covered too. GANG, YOU DON’T. You have to push, pull, and carry heavy things if you want to maintain a strong and fit bod long into your post-retirement years.



I probably could have summed this whole thing up in 5 words:

Use it or lose it.

It’s that simple. Though let’s be real, it’s nowhere near easy.

So here’s today’s tip from me. Go commit that quadriceps comparison picture up above to memory. I did that almost a decade ago and I still think about that picture every now and then; for me it’s the most powerful single photo motivator I’ve ever seen. On lazy days, I pull up that image and BAM. I’m up and going. May it work the same sort of motivation magic on you, too.

Keep the conversation going with comments below. Then go exercise!


Trainer Stef

After 15 years as an educator in both the public K-12 setting and the University level in Special Physical Education, Stef made the leap to her true passion… the fitness world. She’s currently a personal trainer and wellness coach specializing in seniors, medical conditions, and injuries. Stef loves running, cycling, and being “Mugga” to her two favorite mini-humans — Punky and Marshmallow. ❤️

    20 thoughts on “The Truth About Losing Muscle With Age

    1. Chris Hudson

      One comment (a thank you, really) and one playful observation:
      1. I agree with Paul, I “need info like this to get me off my a#$.” Thank you for reminding us.
      2. Uh… isn’t “Use it or lose it” five, not four, words? Maybe an edit is in order?

    2. Viki Anderson

      Being a runner for years and then taking up cycling (due to injuries from running), I can’t agree with you more Stefany! For me lifting weights and power yoga are such an amazing workout and makes me feel so good. However, I always love a great bike ride!

    3. David Hobbs

      Thanks for this reminder Stef. The MRI images really spell out what I’ve known in a way I’ve not seen before. I have kept up the strength training even after my heart attack. My cardiologist doesn’t fully like the load on my heart but knows that functional fitness is important for the reasons you outlined, so he’s given clear rules of what I am allowed to push, pull and carry and how often. I’m pretty good at home, but need to get better about exercise while we are in our RV. I just checked our tube kit and mini-bands this afternoon – and need to get them out of the boot on the road from this weekend! 😉

      1. Stefany - Post author

        Glad the image resonated, and even more glad to hear you’re working on finding your exercise balance post-heart attack. And yes… go get your resistance bands out of the “boot” (your Aussie’s showing, there, lol!)! Happy RVing and happy exercising!

    4. Stephen Monteith Albers

      I’ve often thought that weight loss by itself is incomplete for maximizing the human condition. Another key component is body composition. The concept is easy. But the specific target is hard to determine by test because of the length of the human lifespan. What is your target for optimal percent muscle mass for health and longevity?

      1. Stefany - Post author

        WOO! You opened a big can of worms with that question!!!

        Science hasn’t quite figured out how to efficiently measure muscle mass without the use of technologies such as an MRI, so instead we talk in body fat percentages rather than muscle mass, so let’s start there. The average healthy adult body fat range regardless of age is around 15 to 20% for men and 20 to 25% for women. A woman with more than 32% body fat and males with more than 25% body fat are considered to be at increased risk for disease. Good luck finding any research out there on these percentages though. These are just the generally accepted standards we exercise pros work off, and I can’t point to the research as to where these numbers come from.

        When I’m training someone, I like to see my ladies reach the 12%-30% body fat range, and gents in the 8%-20% range. There’s a variety of ways to measure body fat… skinfold tests, hydrostatic weighing, bod pods, DEXA scans… James and I use a BIA (Bioelectrical Impedence Analysis) scale by Tanita.
        It’s not cheap but it’s given us consistent data on both our body fat percentage, muscle mass (though it can only guesstimate this one based on fat%), and loads of other information like our metabolic ages (WE’RE BOTH TEENAGERS!!!)

        1. Stephen Monteith Albers

          The numbers you cite for males (8% to 20%) fit in with my worldwide reading on the subject of optimal body composition for health and longevity. I offer two other ranges from my reading: 9% to 17% and 10% to 14%. I find it both interesting and useful that all three ranges have an average of 12% to 14%. And, since it is very reasonable that the optimal range is fairly broad, virtually everyone can improve their condition by targeting somewhere in these ballparks.

          Measurement is the bugaboo. Without ACCURATE measurement, the body composition concept is unusable. I tested all technologies and found skin fold, underwater weighing and BIA so repeatably inaccurate as to be misleading and therefore counterproductive. But Bodpod, DEXA and MRI are good enough to be practical. The latter are not very common. But they can be had with a little effort. These tests do not need to be run more than once every 6 months to a year to be very helpful in verifying what is actually happening in an overall fitness regimen.

      2. Stefany - Post author

        There are certainly variations amongst BIA scales and some are truly junk. But don’t completely write off the good ones! After BodPod testing at the University of Utah, I had James jump on our BIA scale, and while it wasn’t perfect, it was within 1% from BodPod!

        Whether or not it’s 100% accurate, which we know BIA scales aren’t, isn’t as important as simply using it as another data point comparing past to present levels. But yes, using one of the more accurate body fat testing measures once a year or so is something I absolutely recommend!

    5. Paul Kennedy

      Excellent information–I am 72 and need info like this to get me off my a#$.
      Perfect timing for me.

      1. Stefany - Post author

        Awesome! One of my favorite things is hearing something I wrote hit at the perfect moment. Get up and get going Paul! Rooting for ya, buddy! xo

    6. Leanne

      As usually sedentary folks, we went today for our orientation at the local hospital’s rehab/ exercise room, paying for a month, since we’ll be here long enough. When the trainer asked about our goals, I said, “to move!”. He liked that, and I’m planning on going to “therapy” 5 days/week, every day they’re open, hoping that calling it therapy will be more motivating than calling it exercise, especially for my husband, who hates exercise.

      1. Stefany - Post author

        Remind him that doing laundry isn’t pleasant either, yet still we do it. Try to think of exercise in that same way, something non-negotiable we just have to do. Wonderful you’ve taken the initiative to sign up for exercise “therapy”! I’m rooting for you both, you’ve got this! xo

    7. Nico Veenkamp

      So true Stef. Your observation about that runners keep on running and cyclists keep on cycling I see everyday. I train my whole body with Tai Chi and QiGong. But what really gets me going is Zhan Zhuang, better known as standing meditation. When you do the ‘hug a tree’ stance you basically do a static training of both legs, core and upper body and hold this for up to an hour.

      What is your opinion about these types of training, especially for the elderly? I know that Harvard did some studies on this regarding fall prevention.

      1. Stefany - Post author

        Exercises like Tai Chi and QiGong are excellent in so many ways. There’s lots of research on their therapeutic benefits and even muscle building (in legs) effects in older adults:

        But I think of these like any of the other modalities (running, cycling, yoga, etc) in that settling on only ONE thing isn’t enough. It’s an excellent enhancement to a healthy lifestyle, but to age well we need more variety, and that includes resisted strength training.

        There’s an interesting study that measured bone density in women with an avg age of 54 who did Tai Chi for a year 5x/week for 45 minutes. Turns out they lost a significant amount of bone mineral density after the year was up, but compared to the control sedentary group, they lost it at a slower rate.
        The study authors tried to stay positive and concluded Tai Chi was beneficial at ‘retarding bone loss’… but come on. They were worse off after a year. Proof that other modalities are necessary for us to get to that MRI picture above of the 70 yr old triathlete.

        1. Lucy Mileo

          Hi Stef. I found you on Silver Sneakers from YouTube with your quickie workout with weights and then your RV workout. Love them both. I am one week from 80 and have been using weights for some time but I find your workouts great. I do one after the other with 4 lb weights. I wonder if the weight matters. I do feel great after your workouts so that tells me something. I have been doing QiGong and Tai Chi and they help with stress and worry, etc and a certain Tai Chi one has almost cured my back stenosis. All in all, I think strength training is the most important and thank you for your excellent workouts. Lucy from Cleveland, OH.

        2. Stefany - Post author

          Hi Lucy! Awwww, you just made my day! So glad you found my old SilverSneakers workouts, and wow I’m impressed you do them back to back way to go! Keep the workouts coming and stay strong, sister! Rooting for you!

          And HAPPY HAPPY BIRTHDAY! May the next year be kind to you, packed with health, laughter, and loads of amazing adventures!!! xo ❤️

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