Muscle mass is a more robust predictor of healthy aging than cardiovascular fitness, body composition, or any other mainstream health marker.
This concept, called “musclespan,” represents the length of time you can maintain healthy skeletal muscle throughout your life—and it’s emerging as the single most critical factor determining not just how long you’ll live, but how well you’ll live those years.
Unlike traditional health metrics that focus on weight loss or cardiovascular endurance, musclespan directly correlates with your ability to survive illness, recover from injury, and maintain independence as you age.
Recent research links low skeletal muscle mass to increased risk of all-cause mortality, while emerging science around myokines—hormone-like compounds released by contracting muscle fibers—reveals that muscle tissue actively regulates inflammation, protects against chronic disease, and promotes longevity.
Men who can perform 40 push-ups have a significantly lower risk of morbidity and death compared to those who can manage only 10.
This stark data point illustrates how functional muscle strength serves as a crystal ball for future health outcomes, making musclespan measurement more predictive than stepping on a scale or checking your resting heart rate.
The implications are staggering: building and maintaining muscle isn’t just about looking good or feeling strong—it’s about creating biological insurance for the inevitable health challenges that await everyone as they age.
Maria’s Transformation: From Weight Loss to Muscle Gain
Maria Arellano Simpson’s journey exemplifies this paradigm shift perfectly. After decades of restrictive dieting starting at age 9, she found herself at 44 carrying an extra 100 pounds, prediabetic, with fatty liver disease and body fat percentage in the 50s.
Traditional cardio-focused approaches had failed her repeatedly, providing temporary calorie deficits but zero additional muscle or strength.
Her wake-up call came through two sick relatives, prompting her to prioritize health for her children’s sake.
“I felt like I owed it to my kids to have the best possible health, and I didn’t want them to have to take care of me when I get older,” she explains.
This motivation led her to discover the concept of musclespan, though she didn’t realize it at the time.
Scrolling through TikTok during her perimenopause transition, Arellano Simpson encountered content that would revolutionize her approach to health.
A strong, athletic trainer from the Ladder fitness app caught her attention, followed by a post featuring a female bodybuilder in her 80s who was “lifting weights, running, just full of life.” These images crystallized a new objective: “chasing muscle instead of thinness.”
The mental shift proved transformative. Instead of the daunting prospect of losing 100 pounds, she focused on “putting on as much muscle as possible” while eating well and adequately. This reframe made her health journey feel like “a quest worth pursuing” rather than another restrictive diet cycle.
After nine months of muscle-focused training, she reversed both her fatty liver and prediabetes.
Her quality of life improvements were equally dramatic: playing with her daughters at the park, climbing stairs with ease, and experiencing virtually no chronic back and knee pain.
“Muscle gives you freedom,” she says. “I know people need to hear about this.”
Defining Musclespan: Beyond Lifespan and Healthspan
While most people understand lifespan (how long you live) and healthspan (how long you remain in good health), musclespan represents the duration you can maintain healthy skeletal muscle throughout your life.
Physician and Women’s Health advisor Gabrielle Lyon, DO, who coined the term, defines it as “living as long as you can with healthy skeletal muscle.”
This distinction matters because skeletal muscle—the muscle attached to bones—differs from cardiac muscle and smooth muscle around organs.
It’s the type of muscle you can actively build and maintain through resistance training, making it the most controllable factor in your longevity equation.
Sarita Khemani, MD, a perioperative medicine physician at Stanford Medicine, frequently encounters the real-world consequences of poor musclespan.
Patients admitted after hip fractures or brain bleeds often suffered falls partially caused by weak muscles.
Having muscle “in reserve” that you built earlier in life acts as armor, helping you better handle inevitable injuries, surgeries, or illnesses.
This preparation becomes increasingly crucial with age. “It’s not if, but when, illness strikes, because it happens to all of us,”
Dr. Lyon emphasizes. “If you are prepared with both strength and mass, then you are much more likely to be able to overcome life’s challenges.”
The beauty of musclespan lies in its accessibility. “The data supports that you’re never too old—and also never too young—to improve muscle health,”
Dr. Lyon notes, making this approach universally applicable regardless of current fitness level or age.
The Surprising Truth About Muscle Priority
Here’s where conventional health wisdom gets turned upside down: most people spend enormous energy tracking metrics that matter far less than the one they completely ignore.
We obsess over daily steps, monitor heart rates, check blood pressure religiously, and track every calorie consumed.
Meanwhile, virtually no one measures or monitors their muscle mass and strength—the very metrics that best predict how long and how well they’ll live.
This represents a fundamental misallocation of health attention. While cardiovascular fitness and body composition certainly matter, Dr. Lyon argues that musclespan not only trumps healthspan but actually dictates both healthspan and lifespan.
The reason lies in muscle’s role as both a metabolic and endocrine organ, making it far more than just the tissue that moves your body.
Muscle isn’t often thought of as an organ deserving as much care as its higher-profile counterparts.
We focus intensively on heart health, brain function, and liver detoxification while treating muscle as merely aesthetic or functional.
“We focus on other organs, like the heart and brain, which are very important. But muscle is a critical organ, especially when it comes to longevity,” Dr. Khemani explains.
This oversight becomes even more problematic when you consider that muscle actively communicates with every other organ system in your body.
Those myokines released by contracting muscle fibers don’t just build more muscle—they “allow muscle to ‘talk’ to other organs, including the brain, adipose tissue, liver, and immune system, helping regulate vital processes like blood sugar control, metabolism, mood, and brain health,” Dr. Khemani details.
The implications extend far beyond physical strength. Muscle health directly connects to metabolic function, cognitive performance, disease resilience, and overall longevity.
This makes muscle mass and strength some of the most powerful predictors of healthy aging, yet they remain largely invisible in standard health assessments.
The Science Behind Muscle’s Protective Power
Emerging research reveals that myokines may explain why exercise decreases chronic disease risk, including cancer, cardiovascular illness, and neurodegeneration.
These powerful messenger compounds enable muscle tissue to regulate inflammation, protect against disease, and promote cellular repair throughout the body.
The protective mechanism works through muscle’s metabolic influence. Muscle tissue contains the mitochondria that utilize oxygen to produce ATP—the molecular energy needed for cellular function.
More muscle mass means more mitochondrial capacity, better oxygen utilization, and enhanced metabolic efficiency across all body systems.
Insulin sensitivity provides a perfect example of muscle’s metabolic importance. Muscle tissue serves as the primary destination for glucose storage and utilization.
When muscle mass declines, the body loses its most effective mechanism for blood sugar regulation, leading to insulin resistance and eventually Type 2 diabetes.
This connection explains why blood markers related to metabolic syndrome—triglycerides, insulin, and glucose—actually reflect skeletal muscle health.
As Dr. Lyon puts it, “All of those are indicators of metabolic syndrome, which is [in actuality] unhealthy skeletal muscle.”
The flip side of peak musclespan is sarcopenia—a disease characterized by declining muscle mass and function.
While often considered an aging disease, sarcopenia actually affects more than 10 percent of adults in their 20s and 30s, making muscle health a lifelong concern rather than something to address in later decades.
This early onset sarcopenia reflects our increasingly sedentary lifestyles and the compounding effects of muscle disuse.
Without regular stimulation through resistance training, muscle tissue begins deteriorating much earlier than most people realize, setting the stage for accelerated aging and increased disease risk.
Practical Strategies for Building Musclespan
Movement as Foundation
“The more active you are, the more you prime your body for muscle,” Dr. Lyon explains. This doesn’t mean structured exercise sessions but rather avoiding prolonged sedentary periods throughout the day.
“One reason muscle becomes unhealthy is there’s no flux. It’s like a pond that becomes a swamp because nothing is moving.”
Getting up and moving at least every 30 minutes provides the basic stimulation muscle tissue requires to maintain health, according to Heather Milton, exercise physiologist supervisor at NYU Langone’s Sports Performance Center.
This frequent movement prevents the metabolic stagnation that leads to muscle deterioration.
However, activity alone cannot build muscle—only resistance training creates the structural changes necessary for musclespan enhancement.
“There’s no replacement for resistance training because [it changes the] muscle fibers,” Dr. Lyon emphasizes.
Targeting Fast-Twitch Fibers
Age-related muscle decline primarily affects fast-twitch muscle fibers—the ones responsible for strength and explosive movement.
These fibers naturally shrink and decrease in number over time, explaining why “you see people go from being buff to being skinny and sarcopenic.”
Maintaining fast-twitch fibers requires specific training approaches combining strength and power work. Dr. Lyon personally integrates power movements like medicine ball slams into her strength workouts, ensuring she stimulates both muscle fiber types in single sessions.
Strength training twice weekly represents the minimum effective dose, according to Deborah Gomez Kwolek, MD, assistant professor at Harvard Medical School.
You can start with basic dumbbell exercises at home and progress to three or four weekly sessions as your capacity improves.
Arellano Simpson exemplifies this progressive approach. She began with 15-minute strength workouts through the Ladder app and now performs four weekly sessions—two lower-body and two upper-body workouts.
Progressive Overload Principles
Effective muscle building requires targeting all major muscle groups—chest, back, legs, shoulders, arms, and core—while providing sufficient stimulus for adaptation.
“Choose a weight that, by the last repetition, you could probably do only about one or two more times before failure, or before your form breaks,” Milton advises.
Training primarily in the hypertrophy rep range of 8-12 repetitions for three to six sets provides optimal muscle growth stimulus.
However, the key lies in continually challenging yourself through progressive stimulus—increasing intensity, volume, and/or complexity over time.
This progressive approach prevents adaptation plateaus and ensures continued muscle development regardless of your starting point or current fitness level.
Protein-First Nutrition Strategy
Muscle building absolutely requires adequate protein intake. Dr. Lyon recommends 0.7 to 1 gram of protein per pound of target body weight, with a minimum of 100 grams daily.
Protein needs increase with age and activity level, making this a dynamic rather than static requirement.
Once protein needs are met, most metabolically healthy people can distribute remaining calories between carbohydrates and fats according to personal preference and energy demands.
This protein-first approach ensures muscle tissue receives the building blocks necessary for repair and growth.
Recovery as a Non-Negotiable
Strength training creates microscopic muscle tears that require at least 48 hours to repair and strengthen.
This recovery period isn’t optional—it’s when actual muscle building occurs. “If you are doing higher-intensity exercise or lifting for the same muscle groups every day, your system doesn’t have a chance to repair that tissue,” Milton explains.
Sleep represents the most critical recovery component. “When we sleep, the hormones that create those adaptations are at their peak,” Milton notes, making adequate sleep duration and quality essential for musclespan development.
The work-to-rest ratio must be optimized for sustainable progress. Recovery isn’t passive—it’s an active process requiring deliberate attention to sleep, nutrition, stress management, and training periodization.
Measuring Your Musclespan: Five Key Assessments
Functional Movement Benchmarks
“I believe everyone should be able to do a push-up, a pull-up, and a good bodyweight squat,” Dr. Lyon states.
These three movements assess different muscle groups and movement patterns essential for daily function and long-term health.
Push-ups serve as particularly powerful musclespan indicators. Research shows that men capable of 40 push-ups have lower morbidity and mortality risk compared to those managing only 10 repetitions.
While comparable female data doesn’t exist yet, similar benefits likely occur with proportionally fewer repetitions.
Target benchmarks include 10 push-ups, 1 unassisted pull-up, and 25-plus squats performed with proper form.
These standards provide concrete goals while revealing current musclespan status across multiple movement patterns.
Grip Strength Testing
Grip strength represents a “fundamental metric” for muscle function and overall physical capacity, recently proposed as a “new vital sign of health.”
This simple test correlates strongly with overall strength and function while requiring minimal equipment or injury risk.
Grip strength testers called dynamometers are readily available through online retailers, making this assessment accessible for home monitoring.
Regular testing provides objective data about musclespan progression or decline over time.
VO2 Max Assessment
VO2 max measures oxygen utilization during exercise and serves as a clinical predictor of early morbidity and mortality risk.
While typically associated with cardiovascular fitness, muscle mass represents one of the main components determining your VO2 max number.
“Muscle is the tissue with the mitochondria that utilize oxygen to produce ATP—which is the molecule needed for contraction,” Milton explains.
This connection makes VO2 max testing another window into musclespan status.
Laboratory VO2 max testing provides the most accurate results, though wearable devices like Apple Watches and Oura Rings offer convenient approximations for general monitoring purposes.
Metabolic Blood Markers
Blood markers related to metabolic syndrome—triglycerides, insulin, and glucose—reflect skeletal muscle health more than most people realize.
Dr. Lyon emphasizes that metabolic syndrome indicators actually represent “unhealthy skeletal muscle” rather than purely dietary or genetic factors.
Quarterly blood work monitoring provides ongoing musclespan insights through these readily available tests.
While most markers appear in routine physicals, fasting insulin testing requires specific requests despite its importance for muscle health assessment.
Body Composition Scanning
DEXA scans provide detailed body composition analysis including muscle mass, bone density, and fat distribution.
While valuable for comprehensive musclespan assessment, cost and accessibility limitations make DEXA scanning more of a beneficial bonus rather than essential monitoring tool.
The combination of functional assessments, grip strength testing, and blood work provides sufficient data for most people to track their musclespan progress and make informed training adjustments.
The Long-Term Musclespan Vision
Musclespan isn’t built overnight, but strategic resistance training, adequate protein intake, and proper recovery create lasting biological protection.
As Dr. Khemani summarizes: “If you want to stay active, independent, and mentally sharp, muscle is necessary.”
The paradigm shift from weight loss to muscle gain represents more than a fitness trend—it’s a fundamental reorientation toward the health metrics that actually matter for longevity.
While society obsesses over numbers on scales, the real numbers that predict your future lie in push-up counts, grip strength measurements, and muscle mass percentages.
Maria Arellano Simpson’s transformation from prediabetic and metabolically unhealthy to vibrant and strong illustrates the practical power of prioritizing musclespan over traditional weight loss approaches.
Her journey from hours of ineffective cardio to strategic strength training demonstrates how the right focus can reverse years of metabolic damage in less than a year.
The most encouraging aspect of musclespan development is its universal accessibility.
Regardless of age, current fitness level, or previous exercise experience, everyone can begin building the muscle mass that will determine their quality of life decades from now.
The question isn’t whether you’re too old or too out of shape to start—it’s whether you’re willing to prioritize the health metric that matters most for your future self.
Building musclespan requires patience, consistency, and a fundamental shift in how you think about health and fitness.
But for those willing to embrace this approach, the rewards extend far beyond appearance or short-term performance.
You’re literally building armor for the challenges ahead, creating the biological resilience that will determine whether your later years are characterized by vitality and independence or frailty and dependence.
