The A in HEALTH, Activity, The Ability to Move Through Life.
- 5 hours ago
- 6 min read
Most people hear the word “activity” and think “exercise.” They picture the gym, running shoes, workouts, programs, and the pressure to do it perfectly.
That is not what I mean by activity in the HEALTH framework.
In the context of healthspan, activity is not the same as exercise. Activity is the ability to move through the world.
It is getting up from a chair without struggle, walking across a room without feeling unsteady, carrying groceries, climbing stairs, turning your head while driving, getting down to the floor, and getting back up again. It is using your body without constantly planning around pain, weakness, or fear.
Exercise is something you do. Activity is what your body can do. As a geriatrician, that distinction matters because the question that predicts the future is not, “Do you work out?” The question is, “What can your body do today, and how quickly is that changing?”
Function matters more than numbers.
Medicine loves numbers. Blood pressure, cholesterol, A1c, and inflammatory markers are treated as the scoreboard.
Biomarkers matter, but they only tell part of the story.
You can have “normal labs” and still be losing function, falling more often, walking slower, and recovering poorly after an illness. You can also have imperfect lab numbers and still move confidently, adapt to stress, and stay independent.
In healthspan medicine, functional status is the real report card. Functional status is how well you can do the physical tasks of daily living, walking, standing, balance, strength, coordination, endurance, and the ability to recover when life throws something at you.
Gait speed, the simplest “vital sign” we ignore
One of the most powerful ways we assess function is also one of the simplest: we watch how you walk.
Walking looks easy, but it is actually a full-body performance. It requires your brain to plan movement, your nerves to carry signals, your muscles and joints to generate and transfer force, your balance system to keep you upright, and your heart and lungs to supply oxygen and energy.
When those systems work well together, walking looks effortless. When something is off, walking slows down.
That is why gait speed is sometimes called the “sixth vital sign” in geriatrics. A meaningful slowdown is often an early warning sign for increased risk of falls, disability, hospitalization, cognitive decline, and loss of independence.
This is not about trying to walk fast. It is about recognizing that slowing is information.
Reserve is the body’s buffer.
Under gait speed is a bigger concept, reserve. Reserve is your biological buffer, your extra capacity, the thing that helps you handle illness, surgery, a medication change, a stressful season, or a fall without tipping into crisis.
When reserve is high, illness is a detour. When reserve is low, illness becomes a turning point. When reserve thins far enough, we call it frailty.
Frailty is not a personality trait; it is a medical syndrome.
Frailty is not a vague label or a personal failing. It is a recognized medical syndrome: a state in which the body has lost enough strength, speed, balance, and endurance that it becomes unusually vulnerable to stress.
Frailty rarely appears overnight. It develops quietly. It often starts with subtle adaptations that seem reasonable, such as avoiding stairs, walking less, feeling uncertain on uneven ground, and stopping activities that used to feel easy.
Over time, the body adapts to doing less by becoming capable of less. The most important thing to know is this: frailty is not inevitable, and it is often dynamic, especially in the pre-frail stage. There is a window where we can intervene early and change the trajectory.
The sedentary trap: why modern life makes us weaker
Modern life has normalized sitting as the default posture. Chairs, cars, screens, elevators, deliveries, and “efficiency” quietly remove movement from daily living. Even if you exercise, prolonged sitting still matters. An hour of exercise does not erase ten hours of inactivity. The body responds to what it does most of the time, not what it does briefly.
When natural movement patterns disappear, such as squatting, floor sitting, carrying, climbing, and frequent walking, we lose human skills that keep joints mobile, muscles strong, and the nervous system coordinated.
This is where NEAT comes in, non-exercise activity thermogenesis, basically all the movement you do outside of workouts. Standing, walking around the house, gardening, taking stairs, carrying groceries, and shifting positions. These “small” movements are not trivial. They keep biological systems awake.
Strength is the organ of independence.
If I had to pick one physical quality that protects healthspan, it would be strength.
Muscle is not decoration. It is a metabolically active tissue that supports blood sugar regulation, insulin sensitivity, balance reactions, recovery from illness, and the ability to remain independent.
Sarcopenia, age-related muscle loss, is not primarily an aesthetic issue. It is a disease process that increases the risk of falls, disability, hospitalization, and loss of independence.
Walking is valuable, but walking alone is usually not enough to preserve strength over time. Muscles need resistance and progressive challenge.
In practical terms, strength after midlife looks like being able to rise from the floor, climb stairs, carry what you need, stabilize when you trip, and recover after illness.
Strength is medicine.
Balance and joint pain, why people stop moving before they should
Most people do not stop moving because their bodies suddenly cannot. They stop because movement no longer feels safe.
Pain teaches avoidance. A near-fall teaches caution. Fear shrinks activity. Then weakness grows, balance worsens, and pain often increases.
Balance is trainable. Joints are designed to move. Appropriate movement, especially strength and guided mobility work, often improves pain and function over time.
Physical therapy is not a last resort. In my practice, I refer early because I would rather interrupt decline than react after a fall.
The key is maintenance. The gains you make in PT disappear if movement disappears.
Endurance, the ability to stay engaged with life
Endurance is not marathons. It is sustained capacity. It is the ability to walk through a grocery store without needing to sit, climb stairs without stopping, travel without crashing for days afterward, and have energy left to live your life.
Endurance builds cardiovascular reserve, supports mood, improves sleep, and protects brain health through improved blood flow and vascular function. It also supports cognitive reserve, the brain’s resilience to aging-related changes.
Movement protects the brain, not just the body.
If your biggest fear about aging is memory loss, you should focus on staying active.
Physical activity supports blood flow, vessel health, blood sugar metabolism, inflammation regulation, sleep quality, and mood. These are upstream factors that shape brain aging and cognitive resilience.
Movement does not guarantee protection from dementia, but it improves the odds, delays decline, and preserves function. It is one of the few interventions that benefit the brain, heart, muscles, and emotional strength simultaneously.
Rebuilding capacity, the return to movement
If you feel deconditioned or discouraged, here is what I want you to hear clearly.
Capacity is not fixed. Decline is not destiny.
If you are in midlife, this is your leverage window. The quiet loss of strength, speed, and endurance that people later blame on aging often starts here. Small, consistent choices now can prevent the slow, gradual narrowing of reserves that shows up years later as frailty. If you are older, it is still not too late. I have seen people in their seventies and eighties rebuild strength, balance, and stamina in ways that meaningfully restore independence.
Start by restoring the basics. Move more frequently. Reduce prolonged sitting. Reclaim balance, joint range, and everyday strength. Build consistency before intensity. Aim for progress, not perfection.
Once those foundations are in place, structured strength training and cardiovascular training become powerful tools. Resistance builds muscle and metabolic resilience. Endurance training expands cardiovascular reserve and supports brain health. These are not athletic goals; these are strategies to build a buffer.
Movement is not an add-on. It is foundational. It is the beginning of medicine. And when layered intentionally, it becomes one of the most powerful ways to protect healthspan.
A simple starting point
If you want a practical way to begin, use this lens:
Move more often, stand up, walk, and change positions.
Strength matters; add resistance, even light or modified.
Balance is practice; do safe challenges consistently.
Endurance is sustainability, build time, not punishment.
Treat movement like hygiene, not a project you finish.
Closing, the A in HEALTH is about agency.
The A in the HEALTH framework is not about becoming an athlete. It is about preserving the capacity to live your life, on your terms, for as long as possible. It is about independence. It is about reserve. It is about protecting the buffer that keeps small problems from becoming life-changing ones.
This is the work of Healthspan.
Learn more about the HEALTH framework from me, Dr. G, the Geriatrician and Lifestyle Medicine Expert.
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