03/31/2026
Here's the second article of the trilogy on Substack. Link to the full article with references in the comment section below.
Rougher Seas in Midlife: “Doing More, Getting Less”
Midlife Reset Series, Part 2
In the first article of this three-part series, “Midlife Reset: Captain Muscle, Steering Health in Midlife,” we talked about muscle as more than strength. Muscle helps us move with power and agility, but it also acts like an organ. It sends out helpful signals that can lower inflammation and communicate with the liver, fat tissue, brain, and immune system. We also covered the cost of losing muscle, how it links to chronic disease, and how the back-and-forth conversation between muscle and brain may support brain health.
In this second article, I want to share what changes in our musculoskeletal system in midlife and beyond. This topic is personal for me, because I’m feeling these shifts as many of you are, and I’m learning how to work with them instead of fighting them.
At first, I assumed the story would be mostly about hormones. So I did a deep dive into how hormonal shifts affect men, women, and transgender people. What I found surprised me: hormones matter, but they are not the whole story, and not even close. Underneath, the bigger driver is aging biology. The same basic changes in muscle and recovery show up in all humans, even though the timing and intensity can look different from person to person.
To make this digestible, I’m going to walk through five key topics:
Hormone acknowledgement
Muscle quantity and quality
Recovery biology
Inflammaging
Bones and tendons
Think of this article as the foundation. In the final article of the trilogy, we’ll talk about practical ways to protect your spine and joints, and build strength that lasts.
I. HORMONE ACKNOWLEDGEMENT
S*x hormones matter, but they are modifiers, not the whole story. However, midlife comes with real hormonal shifts, and those shifts can change how your body feels and performs.
Let’s start by describing hormonal changes, and get clear view of what they can vs cannot explain.
Estrogen and testosterone can affect how quickly you lose muscle, how you feel day to day, how you recover, and where you tend to store fat. But the deeper, age-driven processes that chip away at muscle function keep moving forward in all humans, across all sexes. Hormones can change the speed and the feel of midlife changes, but aging biology is the bigger engine underneath.
Women: menopause is an inflection point, not the full explanation
For many women, peri-menopause and menopause is the moment the “rules” seem to change suddenly. Estrogen levels decline, and studies link this transition to changes in muscle strength and muscle quality. Some women notice they feel weaker, stiffer, or more sore than they expect. Others notice that their body composition shifts, especially around the midsection, even when their routines have not changed much.
But menopause is rarely the only thing going on.
Midlife is also when sleep often gets lighter, stress gets heavier, and daily movement declines. So menopause can steepen a slope that was already forming. It can reveal a trend that was building from aging, less activity, poor sleep, chronic stress, and changes in body composition.
Another thing that happens to my female patients in their 40s and 50s is that “everything starts hurting.” Is it just menopause? No, but it should be considered.
The relationship between menopause and inflammation is a good example of how menopause, along with the accompanying decline of estrogen, is not always correlative with inflammation. Long-term data following women through the menopause transition shows there isn’t one single inflammation pattern. Some women show rises in inflammatory markers like hs-CRP and IL-6 near the final menstrual period, while others stay stable or even go down. These patterns often track with baseline inflammation, visceral fat, and other factors that can vary between people.
That being said, I also have female patients who start experiencing conditions such as frozen shoulder (or other joint pains) and start feeling better after starting Estrogen. There is also research supporting the sharp drop in estrogen levels during this transition affects connective tissue health, leading to reduced elasticity, increased inflammation, and abnormal collagen metabolism—key factors in the development of shoulder stiffness and fibrosis. In this scenario, estrogen is playing a role.
For many women, the menopause transition can add fuel to the fire and make us feel weaker, achy, and sluggish. We just have to keep in mind that menopause can’t take the blame for everything.
Men: testosterone declines gradually, body composition changes are clearer than performance changes
In men, testosterone tends to decline more slowly over time. Lower testosterone is linked, in many studies, with lower lean mass and higher fat mass. That relationship is fairly consistent.
When testosterone is replaced in older men with confirmed low testosterone, studies show a pattern: lean mass tends to increase and fat mass tends to decrease. Where the story gets more complicated is function. Strength and physical performance do not always improve in a big or consistent way across trials. The decision to use testosterone therapy is not a simple “more is better” situation. It depends on symptoms, confirmed labs, and a careful medical risk-benefit conversation.
In short, testosterone matters, but it does not override aging biology, nerve-to-muscle changes, and lifestyle. It can shift the slope, but it does not replace the foundation.
Transgender people: hormone therapy changes muscle and fat, but aging biology still applies
I also want to include transgender people here, because hormone shifts are not only a “midlife” issue for everyone. For some people, hormone therapy is gender-affirming care, and its effects on the body can occur on a faster timeline than typical aging changes.
The shared principle is straightforward: raising or lowering estrogen and testosterone predictably shifts lean mass and fat mass, and it can change hemoglobin and certain performance-related measures. This is well-described in the medical literature.
In transgender women on feminizing hormone therapy, studies often show decreases in lean body mass and strength after starting therapy, although strength may remain above average compared to cisgender women in some cohorts, depending on baseline muscle, prior training, and how long someone has been on therapy.
In transgender men on testosterone therapy, studies generally show increases in lean mass and strength, with a range depending on starting point, training background, and how outcomes are measured.
What is different here is the timeline and the baseline. Hormone therapy can shift body composition and strength over months to a few years, which can feel faster and more noticeable than typical aging-related changes. And people start from different baselines, depending on puberty exposure, training history, and time on hormones.
Some key takeaways about hormones:
Hormone therapy can change the decline of muscle and fat changes, but it does not turn off the universal biology of aging.
Over time, the same aging processes still affect muscle quality, tendon load tolerance, inflammation tone, and recovery capacity, regardless of gender identity.
Regardless of hormones, as we age, our musculoskeletal and nervous systems become less responsive and less efficient. That is why focusing only on hormones misses the larger story of midlife biology
II. MUSCLE QUANTITY & QUALITY
Most people think muscle loss is an “old age” problem, or an issue after you have been hospitalized. They think of this as something that starts in your seventies, or after being stuck on the couch recovering from surgery.
But muscle change starts earlier and in a sneaky, ninja-like fashion. For many people, it begins in the 30s to 40s, then becomes harder to ignore in our 40s to 50s. It shows up in two different ways: 1) how much muscle you have (quantity) and 2) how well that muscle works (quality).
If you only focus on how big your muscles look, you miss the real story.
Muscle quantity: slow fade
Over time, muscle size tends to shrink. The change can be subtle at first, and it may not show up on the scale. This matters because muscle is required for all basic functions: getting up from a chair, picking something up off the floor, climbing stairs, running through the airport to catch a flight.
This is why researchers who study age-related muscle loss, often called sarcopenia, don’t define it by appearance. Sarcopenia is the medical term for age-related loss of muscle strength and function. It’s not just about muscle size. In fact, experts now define it mainly by low strength, because strength is what best predicts falls and loss of independence. Muscle mass and muscle quality help confirm it, and physical performance measures show severity. So sarcopenia is less about how you look and more about what your body can do, and midlife is when the earliest signs often start to matter.
Muscle quality: feeling weak
I hear this from patients all the time: “I’m the same weight and my muscles look the same, but I feel weaker.” You can keep a decent amount of muscle, look great in your Instagram photograph, but surprisingly, feel weaker. This isn’t just imagination.
You can keep a decent amount of muscle and still lose performance. With age, muscle can change from the inside out. It may develop more fat infiltration and more connective tissue stiffness within and between fibers. That means less force per pound of muscle where you have less spring, less speed, less power.
Aging also tends to affect fast-twitch fibers more than slow-twitch fibers. Fast-twitch fibers are the ones that help you move quickly, generate power, and react quickly. When those fibers shrink or disappear, it often shows up as “I don’t feel as explosive,” “I’m slower,” or “my legs don’t have the same pop.”
The brain-muscle connection changes, too.
Muscle is not just tissue that stands on its own. There is a relationship between muscle fibers and the nervous system.
As we age, the wiring from nerve to muscle remodels. Motor units, the bundles of nerve fibers that control groups of muscle fibers, become fewer and less precise. The body adapts by “reassigning” muscle fibers to surviving nerves, but the end result is often less smooth control and less efficient activation.
This matters because you do not lose strength only because the muscle shrinks. You also lose strength because your nervous system becomes less efficient at turning the muscle on.
That’s why people often notice shakiness under load, less coordination when they’re tired, or a longer warm-up before their body feels like it “belongs” to them again.
Even fit athletes are not protected from this change. One of the most humbling findings in the aging literature is that training helps a lot, but it does not make you immune to biology. Studies of highly trained older athletes show that performance still declines with age, even when people stay consistent. It’s because the baseline physiology shifts under the surface for all of us.
Muscle quantity and quality are in the spotlight of the midlife story. Once muscle becomes less responsive and less efficient, the whole system feels different.The same stress can hit harder. The same workout can cost more. The same busy week can leave a deeper dent, physically and mentally.
And that is exactly why, in the next sections, we’ll look at what changes in recovery biology and inflammation, and how those changes layer onto the muscle story.
III. RECOVERY BIOLOGY
In our 20s and 30s, recovery can feel automatic. You work out hard, you bounce back. You may even lose sleep and still go to work, get to the gym, go out all weekend and do it all again. Sound familiar?
In midlife, the biology of recovery changes. Post-workout soreness can last longer, progress can feel slower, and we become injury-prone. How many of us wake up with “bed injuries”? I’ve gotten beaten up by my bed more than once.
When it comes to recovery, here are a few shifts happening under the surface.
Sleep gets lighter, and recovery becomes less automatic
Midlife is when a lot of people start sleeping differently. Even if you’re still getting “enough hours,” the quality can change. We wake up more often and our sleep is lighter.
Sleep isn’t just about rest, but a time when your body shifts into repair mode. Time spent in your bed now has a more profound meaning, as this is when your muscles rebuild, inflammation settles down, and your nervous system resets. When sleep is broken, the next day often feels like crap. Workouts feel harder, soreness is prolonged and small stressors feel inflated.
Your body becomes less efficient at rebuilding muscle
Another change that becomes more obvious in midlife is that rebuilding doesn’t happen as easily as it used to. Thumbs down. Scientists call part of this anabolic resistance. It means your muscle doesn’t respond as strongly to the usual “build and repair” signals, especially protein and exercise.
This is one reason people can train the way they always have, eat the way they always have, and still notice they aren’t getting the same return. The signal-to-response relationship changes. The good news? Your body still adapts, it just requires a clearer signal over time.
This is also why recovery isn’t only about time off. Recovery is about biology, the body’s ability to flip from stress into rebuilding.
Your nervous system gets a recovery budget too
Heavy training, high intensity intervals, lack of sleep, and life stress all compete for the same recovery resources. That’s why some people feel wiped out even after a workout that was not that long. It’s not just the muscle fibers that need this rest, it’s the whole system that recruited them. We have to allocate the recovery budget across various systems in the body, not just the muscles.
This also ties back to the nerve-to-muscle wiring changes we talked about earlier. If the nervous system is less efficient with age, it often takes more effort to produce the same output, and effort has a cost.
Midlife recovery reveals what your body can tolerate consistently
One of the biggest shifts in midlife is that “hero workouts” stop working as well. In younger adulthood, you can get away with random bursts of intense exercise followed by long gaps. In midlife, that pattern often backfires, because your tissues adapt best to what you do repeatedly, not what you do occasionally.
Midlife bodies often do better with training that is repeatable. Not easy, just repeatable. The kind of training you can do again next week without breaking down.
To summarize this section, midlife recovery is not about toughness or willpower. It is not simply about resting your muscles. It’s about understanding physiology, how your entire body needs resources to recover and how to optimize accordingly.
Next, we’ll talk about another system that changes in midlife and can make recovery even harder: baseline inflammation, what researchers often call “inflammaging.”
IV. INFLAMMAGING
One of the biggest midlife shifts is something you can’t always see on the outside. It’s more like a background setting in the body that slowly turns up over time. Researchers call this “inflammaging.”
Inflammaging is a low-grade, chronic inflammation that tends to rise as we get older, even when we are not sick. This isn’t about experiencing the inflammation due to a fever or a sprained ankle. It reveals itself as “background noise.”
In midlife, inflammation, or “Inflammaging” often shows up as:
feeling more sore from the same workout
taking longer to recover
feeling more stiff in the morning
feeling “puffy,” achy, or run down for no obvious reason
None of these symptoms are scientifically proven to be caused only by inflammation. However, any of the symptoms, or combination of symptoms, are clues that the internal environment is changing.
Where does this low-grade inflammation come from?
Inflammaging isn’t one thing but usually due to multiple factors. Here are a few of the biggest drivers:
Visceral fat
Not all body fat behaves the same. Visceral fat, the fat that collects deep in the abdomen around organs, is more inflammatory than the fat you can pinch under the skin. It releases chemical signals that can push the body toward insulin resistance and higher inflammation. This helps explain why midlife weight gain, especially around the belly, can feel like it changes everything, energy, sleep, cravings, and recovery. When I first learned how inflammatory visceral fat can be, I was honestly grossed out. It made me look at my habits differently and implement some changes.
Sleep disruption
When sleep gets shorter or more broken, the immune system shifts into a more reactive state. There are studies that show that sleep restriction can raise inflammatory markers like IL-6 and CRP. That matters because inflammation doesn’t just affect long-term health. It changes how you feel tomorrow, when you wake up.
Stress
Chronic stress is not just mental. It causes chemical changes in your body. Over time, stress can shift cortisol rhythms, increase sympathetic tone, and keep the body in a “fight or flight” state. Stress doesn’t directly cause autoimmune arthritis, but it can worsen flares. The stress response also tightens muscles and changes how your nervous system processes pain. Your pain tolerance is lower. This can make a minor tissue irritation feel like a major injury. This shift into a catabolic, inflammatory state, can also
Why inflammaging matters for muscle
Tying this back into “Captain Muscle”, muscle does not just grow or recover because you “work out hard.” It adapts based on the environment it’s in. Inflammaging changes that environment.
When inflammation is higher:
muscles can become less responsive to the usual signals from exercise and protein
soreness can last longer
training can feel harder than it should
the body can be more likely to break down than build back up
Inflammaging is one of the reasons midlife can feel noticeably different. It can change how your body feels during daily life, how you recover from workouts, and how well you use protein to rebuild.
Next, in the final section, we’ll zoom out again and look at the support structures that carry your muscle power through the real world: bones and tendons.
V. BONES & TENDONS
We all know that muscles don’t work on their own. Muscles pull on tendons. Tendons pull on bone. Bones support the whole system. When any one of these tissues falls behind, it changes what your body can tolerate, and how you navigate the world. It’s important to understand why you can’t just focus on building your muscle and how this can even be detrimental.
Bones: strength isn’t just density
Bones are living tissue that are constantly breaking down and rebuilding. When we’re younger, that balance usually stays fairly even. Over time, that balance can shift, so more bone is broken down than rebuilt. That’s one reason why fracture risk rises with age.
But bone health is not only about density. Bone also changes in structure. With aging, the outer layer of bone can become more porous, and the architecture can weaken even when the bone density number doesn’t look terrible on paper. That is one reason two people can have similar bone density results, but very different bone strength.
For women, this becomes especially relevant around perimenopause and menopause, because estrogen helps protect bone. When estrogen declines, bone turnover can speed up, and bone becomes more sensitive to how it is loaded. This is a time when bone can change faster than expected.
For men, while osteoporosis is less common, I’ve seen multiple cases where osteoporosis was only discovered after a sudden vertebral compression fracture. Men can’t assume their bones will stay strong forever.
Patients often wonder if they can fix their brittle bones with supplements. A key point that often gets missed is that while supplements support bone, they do not replace the main signal bone needs. Bone responds to mechanical loading. It learns from force and adapts to what you ask it to carry.
That’s why exercise shows up again and again in the bone health literature. In a well-known study of postmenopausal women with low bone mass, a supervised high-intensity resistance and impact training program improved bone mineral density and physical function. In other words, bone can respond, even later in life, when the loading is appropriate and progressive.
Tendons: the slow tissue that transfer the load
Tendons are the thick cables that connect muscle to bone. They allow force to transfer through the body so you can walk, run, lift, climb, and catch yourself when you trip.
With everything we have discussed already, what else can start taking a turn? In midlife, not only does it become harder to maintain muscle function, tendons are often the bottleneck in our overall musculoskeletal system.
What does this mean? An unfortunate midlife reality is that muscles can regain strength faster than tendons can keep up. Tendons are slower tissues. They don’t have the same blood flow as muscle, and their remodeling process is slower. With age, collagen turnover and tissue healing capacity change, which helps explain why tendon pain becomes so common in midlife.
This is why someone can feel “cardio fit” and feel strong, and still get derailed by an Achilles tendon flare or an irritating elbow tendonitis. This is not always a sign that something is torn or broken. Sometimes it is a sign that tissue capacity is lagging behind the demand being placed on it.
There’s another layer to consider. In addition to a slower rebuild, collagen can accumulate more crosslinks, including changes related to advanced glycation end products overtime. This can make tissues less elastic and less forgiving. Tendons may handle rapid spikes in training load poorly, even when the muscle feels capable. In the clinic, I see overuse injuries and sudden tendon injuries from desk jobs, gardening and relatively benign gym workouts.
KEY: It is important to consider the tendon system as the speed limit, even when the muscles feel ready to go.
Unfortunately, when tendons are irritated, patients naturally back off on exercise. When activity drops, muscle declines faster. When muscle declines, the body loses joint protection and balance, which increases stress on tendons and bones. This is a terrible Catch-22 where my patients will start avoiding activities, feeling worse because of it, and spiraling downhill. The good news is that instead of avoiding pain, you can work through them. Having been a patient myself on numerous (too many) occasions, can also attest to this.
And now that we’ve laid out what changes, hormones, muscle quality, recovery biology, inflammation, and the bones and tendons that carry it all, the final article in this trilogy will shift into action: what to do about the midlife changes, and how to train efficiently and work with biology.
See you next time!
