Amid growing buzz around lifespan and healthspan, a new “span” is entering the conversation: musclespan. Coined and championed by Dr. Gabrielle Lyon, the term shifts the focus toward how long our muscles remain strong, functional, and metabolically healthy. It’s an increasingly important distinction as more evidence links muscle health to cognitive health, metabolic function, and all-cause mortality.
If you’re an avid Muscle & Fitness reader, you care about muscle and already understand its value as a longevity organ. Yet Lyon worries that even now we may be missing the bigger picture.
“With the rise of widely available weight loss solutions, many people still prioritize focusing on losing fat as opposed to building muscle,” Lyon, a board-certified physician and founder of Muscle-Centric Medicine, told M&F. She believes we’re standing at familiar crossroads. “The obesity epidemic really started in the ’70s,” she explains. “But at the same time, there was absolutely no mention of muscle health. Skeletal muscle wasn’t even formally recognized as an organ system until the early 2000s.”
Now, she warns, history may be repeating itself. “I have concerns we’re going to repeat what we did in the ’70s with the use of GLP-1s without training and appropriate protein,” she says. “Patients 100% will lose muscle, and no physician is prepared to deal with it because we’ve never been in this position ever.”
What Is Musclespan?
Lyon defines musclespan as the length of time your muscle stays functional, strong, and metabolically healthy. And not just during your peak years, but how well that tissue holds up over decades.
Skeletal muscle plays a central role in long-term health outcomes. According to Lyon, many of the conditions that accelerate aging and increase all-cause mortality risk are not primarily diseases of fat, but of compromised muscle.
“When we think about longevity, what are the outcomes we want to avoid?” Lyon raises the question. “Dementia, cardiovascular disease, obesity, diabetes, all of which are not around the pathology of fat, but focused on the health of skeletal muscle.”
Musclespan positions skeletal muscle as a central organ system that influences metabolic control, vascular health, and brain function simultaneously. In Lyon’s point of view, preserving muscle quality and function over time is foundational to aging well.
“The question isn’t just how strong you are now,” she says. “It’s how long your muscle stays healthy enough to protect you.”
Musclespan’s Connection to Brain Health
One of the least appreciated roles of muscle is its connection to brain health and cognitive function.
“We know that the stronger the leg muscles, the better the cognition,”Lyon says, noting that resistance and aerobic training both play a role.
But the relationship goes deeper than improved blood flow. “A large portion of the brain is designed for movement,” Lyon explains. “If you are not exercising your body, then there are portions of your brain you are not maintaining. There’s this bi-directional relationship.”
Even movement speed matters. “The faster you move, the faster you think,” she says, describing how the speed at which you move is linked to processing speed and mental tasks.
Why Aging Makes Muscle Harder to Build and Easier to Lose
A major challenge to musclespan is that muscle tissue changes with age.
“It becomes more difficult as you age not just to put on muscle, but to maintain muscle,” Lyon says. “The tissue becomes more anabolically resistant, meaning it’s less efficient at utilizing protein.”
Compounding the problem is what she calls a “dietary mismatch” for muscle health.
“The average American is eating 300 grams of carbohydrates a day,” Lyon notes, “which is essentially three glucose tolerance tests.” When muscle makes up roughly 40 percent of body weight, chronically overfeeding carbs while underfeeding protein has consequences.
“If muscle is chronically inflamed or has low-grade inflammation,” she says, “that’s a problem.” One of the fastest ways to make muscle “really sick,” she adds, is to stop loading it and stop nourishing it appropriately.
The Non-Negotiables for Musclespan
In her new book, The Forever Strong Playbook, Lyon takes the science of muscle-centric medicine and turns it into actionable guidance around what to do day to day to protect your muscle. The structure is intentional encompassing four main pillars.
How to think
The Playbook opens by helping readers clarify their why, identify blind spots, and prepare for discomfort. “We expect things to be easy, and then when they’re hard, we throw in the towel.” Lyon says. Instead, Lyon emphasizes setting standards and staying consistent accordingly rather than chasing goals, approaching muscle health as a long-term responsibility.
How to eat
Nutrition in the Playbook gets a simple refresh. Rather than complex tracking, Lyon focuses on building plates that support muscle health by prioritizing adequate, high-quality protein and aligning intake with physical activity. “The first decision you make is how much protein you eat,” she says, noting that protein needs to increase with age as muscle becomes less efficient at using it. The Playbook emphasizes minimum effective doses, diet quality, and getting the first meal of the day right to support muscle turnover and metabolic stability. Also, the recipes are worth every bite.
How to train
Whether you’re a beginner or want to get back in the saddle, Lyon’s programs are scalable for all levels, ranging from dumbbell-only workouts to more advanced resistance training, and focus on progressive stimulus rather than overload. “Progressive overload just means heavier,” she explains. Instead, she encourages switching up tempo, time under tension, and movement variety to build resilient muscle while protecting joints and connective tissue over time.
How to recover
The Playbook includes strategies to help downregulate the nervous system, align circadian rhythms, and support adaptation recognizing that muscle is built in the spaces between sessions. “Transformation doesn’t happen when you’re actively doing the thing,” Lyon says. “It really happens when you are recovering.”
Lyon designed a six-week action plan with daily routines, visual frameworks, and simple reflection prompts that make consistency more achievable. Ahead of the Jan. 27 book launch at Life Time in New York City, Muscle & Fitness got an exclusive early look inside of what Weeks 1 and 2 of Lyon’s six-week training plan looks like. Here’s a sneak peek:
‘The Forever Strong Playbook’ Workout
Weeks 1-2:”
Session 1
Warm-up:
- LUNGE TO REACH: 5 reps, each side
- Reach up, not back, from a lunge position to lengthen the spine and maintain stability, keeping the knee aligned with the toes.
- CHILD’S POSE: Hold for 20-60 seconds
- Sink your hips back without forcing the stretch. Relax the shoulders, bring the forehead to the mat, and breathe deeply into the lower back.
Working Set: The following exercises include tables to track sets, reps, range, weight, and RIR (Repetitions in Reserve).
- PUSH-UP: 3 sets, 10-20 reps
- Keep the body in a straight line from head to heels, engage the core to prevent the lower back from sagging. Lower slowly, keeping elbows at about a 45-degree angle to the body.
- DUMBBELL ROMANIAN DEADLIFT (RDL): 3 sets, 6-15 reps
- Maintain a slight bend in the knees while hinging at the hips. Keep the dumbbells close to the body and focus on squeezing the glutes when rising.
- GOBLET SQUAT: 3 sets, 6-15 reps
- Hold the dumbbell close to the chest with elbows pointed down. Drive through the heels, keeping the chest lifted and back neutral throughout the squat.
- DUMBBELL ROW: 3 sets, 6-15 reps
- Hinge forward at the hips, keeping the back flat and core engaged. Squeeze shoulder blades together to pull the weight toward the hip with the back (not arms). Keep the torso stable.
- SIDE PLANK: 3 sets, 10-30 seconds
- Keep the body in a straight line from head to knees and engage the core. Ensure the elbow is directly under the shoulder and avoid letting the hips sag toward the ground.
Cardio Finisher:
- CHOOSE YOUR HARD: Complete 3 sets of 15 seconds on, 45 seconds off.
- Options include Airbike, Rower, Sled, or Sprints (for those with proper running technique)
