Exercise may do far more than improve fitness and mood during cancer treatment.
According to neuroscience expert Louise Nicola, emerging research suggests physical activity could actually interfere with cancer’s ability to spread throughout the body.
In a recent episode of The Neuro Experience podcast, Nicola broke down fascinating new evidence linking high-intensity exercise to reduced metastatic potential through multiple biological mechanisms.
What she revealed challenges traditional thinking about exercise’s role in cancer care—and offers hope grounded in hard science.
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Blood Flow as a Cancer Defense Mechanism
One of the most striking mechanisms Nicola described involves something called shear stress—the physical force blood exerts as it rushes through vessels during intense exercise.
Microfluidic studies published in PNAS and Nature Communications exposed human cancer cells to flow conditions mimicking increased blood flow. As shear stress increased, survival of circulating tumor cells decreased.
When I say sheer stress, okay, I’m talking about the shunting of blood when you are in zone five. Remember zone five is that 90% of maximum heart rate or above. Think about it on the stair master at the gym on level 15 and above. You’re fighting for your life.
That intense cardiovascular effort creates a hostile environment for tumor cells trying to establish themselves elsewhere in the body.
Nicola emphasized this doesn’t mean someone can simply “run away” from metastasis. But repeated bouts of increased blood flow could make the circulatory system less forgiving to cancer cells attempting to spread.
Exercise creates biological and mechanical conditions to make several steps in the metastatic process more difficult. We want to make it difficult for them.
That’s meaningful because metastasis—not the original tumor—is what ultimately kills most cancer patients.
Immune Surveillance Gets Supercharged
Beyond physical forces, exercise dramatically influences immune function in ways that could suppress malignant cells.
Physical activity mobilizes natural killer cells and cytotoxic T cells—your body’s frontline cancer fighters. In preclinical models, exercise increased immune cell infiltration directly into tumor tissue.
Exercise is repeatedly activating and redistributing immune function. And immune function is central to suppressing malignant cells.
While human evidence remains more complex than animal studies, the underlying concept is clear: consistent exercise keeps immune surveillance systems active and alert.
This repeated activation may help identify and eliminate rogue cells before they can establish new tumors.
Metabolic Signaling and Growth Factor Control
Nicola highlighted another critical pathway: metabolic signaling.
Exercise improves insulin sensitivity and lowers insulin and IGF-1 signaling—growth factors that cancer cells often exploit. Physical activity also reduces chronic inflammation, changing the biochemical signals available to residual malignant cells.
These metabolic improvements create an internal environment less conducive to cancer growth.
Think of it as changing the soil, not just attacking the seeds.
Muscle Mass as Survival Currency
Cancer treatment often depletes the body’s physiological reserves. Muscle mass becomes particularly critical during this period.
Imaging prognostic studies show patients with low muscle mass face higher risk not only for physical decline but also for worse long-term outcomes.
Survivorship often involves rebuilding from a state of physiological depletion and the patients with low muscle mass are at a higher risk not only for physical decline but also for worse long-term outcomes.
Maintaining or rebuilding muscle through resistance training becomes a form of metabolic insurance during and after treatment.
Realistic Expectations Matter
Nicola was careful to temper excitement with scientific honesty.
Exercise is not a guarantee and it’s not an insurance policy in the sense people emotionally want it to be because biology doesn’t make promises.
However, exercise remains one of few interventions showing benefits across the entire cancer continuum—from reducing initial risk to improving treatment tolerance to potentially influencing recurrence and metastatic potential.
This evidence has elevated exercise from “nice to have” to a pillar of modern oncology care.
Important Limitations to Acknowledge
Not all cancers show identical relationships with exercise in prevention studies. Cancer isn’t one disease—it’s hundreds.
Not all patients can tolerate the same intensity during treatment. Certain conditions can be exacerbated by exercise, including:
- Severe gastrointestinal toxicity
- Radiation-related skin injury
- Neuropathy
- Bone metastases with fracture risk
While randomized trials for fatigue, function, and treatment tolerance are strong, evidence regarding survivorship and recurrence is still developing.
Observational evidence in colon and breast cancers is compelling but doesn’t carry the same weight as randomized controlled trials.
A Decision Framework, Not Just a Workout Plan
Nicola offered practical guidance tailored to different stages of the cancer journey.
For Prevention
Meet public health guidelines for moderate to vigorous physical activity, plus resistance training.
Evidence shows both aerobic capacity and muscle mass are biologically protective.
During Treatment
Shift focus from performance to preservation.
The goal is not performance, it’s preservation. Meaning, preserve muscle, preserve function, preserve sleep, preserve mood, and support treatment completion.
Combine aerobic and resistance exercise scaled to individual tolerance, ideally within medical guidelines.
As a Survivor
Rebuild physiological reserves that treatment eroded.
Continue patterns of repeated immune and metabolic signaling by regaining muscle mass, strength, and aerobic capacity.
The Bottom Line
Exercise doesn’t work as a motivational concept or emotional crutch.
It works as repeated physiological stress that remodels metabolism, immunity, circulation, and muscle—the very systems cancer interacts with at every stage.
That mechanistic understanding transforms exercise from generic health advice into targeted biological intervention.
While questions remain and individual cases vary, the emerging science suggests movement may be one of our most powerful tools in making the body an inhospitable place for cancer to thrive.
