Small Steps, Big Living: Why Movement is Medicine – Sami Mansfield

“Part 2: Exercise in Oncology: Why Movement is Medicine.

Exercise is one of the most powerful tools in cancer care. But despite decades of evidence, it remains underprescribed, underutilized, and undervalued.

That must change.

From prevention to survivorship, movement does more than maintain fitness. It reduces treatment toxicity, improves recovery, strengthens immunity, and can even improve survival outcomes on par with some of our best therapies.

What the Newest Research Is Telling Us

At the 2025 ASCO Annual Meeting, a landmark randomized controlled trial revealed that structured physical activity reduced recurrence by 28% and death by 37% at 8 years in survivors of stage III and high-risk stage II colon cancer. The program began after surgery and chemotherapy – reinforcing that it’s never too late to start moving.

These benefits rival those of leading adjuvant treatments. Yet how often is exercise discussed with patients with the same urgency?

These benefits rival those of leading adjuvant treatments. Yet how often is exercise discussed with patients with the same urgency?

This trial builds on the foundation set by the Exercise, Diet, and Weight Management During Cancer Treatment: ASCO Guideline (Ligabel, 2022)

These evidence-based recommendations emphasized that exercise is safe, feasible, and beneficial during active cancer treatment – helping to reduce fatigue, preserve function, and support emotional well-being. But like any guideline, its true power lies in implementation. The latest research reinforces the message: exercise is not optional – it’s integral to cancer care.

The Immune-Boosting (and Glucose-Balancing) Role of Muscle

Movement isn’t just about energy and strength – it changes your biology.

Muscle tissue functions as an endocrine organ, releasing myokines, which are anti-inflammatory molecules that may inhibit tumor growth and enhance immune surveillance (Huang, 2022.) But that’s not all—muscle is also the body’s largest site for glucose disposal, playing a vital role in blood sugar regulation and metabolic health.

This is especially important for cancer survivors, many of whom experience metabolic disruptions from treatment—such as insulin resistance, weight gain, or loss of lean mass. Maintaining and rebuilding skeletal muscle supports better glucose control, reduces systemic inflammation, and enhances metabolic resilience—making it essential in the long game of survivorship.

Emerging research (Mialich, 2025) shows that muscle mass is a stronger predictor of survival than weight, particularly in breast, colorectal, and lung cancers. The outdated advice to “just rest” after treatment often does more harm than good. What many survivors need is targeted, progressive movement that promotes healing and restores function.

The Only Proven Way to Preserve Muscle

While all types of movement have value, resistance training stands alone as the only intervention proven to maintain or rebuild muscle during and after treatment. This is vital not just for strength and mobility, but for:

• Reducing fatigue
• Improving treatment tolerance
• Enhancing metabolic health
• Supporting mental well-being and cognitive function

And it doesn’t have to be fancy. Bands, bodyweight, or light dumbbells can all be effective with the right guidance.

Guidelines vs. Reality

The American Cancer Society and American College of Sports Medicine recommend:

• 150 minutes of moderate-intensity aerobic activity per week, plus
• At least two strength training sessions weekly

But fewer than 20% of cancer survivors meet these targets. Most don’t lack motivation—they lack guidance, clarity, and support. That’s where we come in.

Action Over Intention: Sit Less. Build Strength.

If you’re a survivor:

Start with strength you can do at the kitchen counter. Try countertop push-ups—2 sets of 8–10 reps a few times a week. Break up long periods of sitting with simple movement “snacks” like calf raises, wall sits, or gentle marches in place. You don’t need to do it all at once—just more than you did yesterday.

If you’re a clinician:

Don’t wait until after treatment is over—prescribe movement as early as possible. Emphasize strength-building as a key part of recovery, not an afterthought. Connect patients to exercise professionals trained in oncology and help normalize movement as part of the care plan, not outside of it.

If you’re supporting a loved one:

Create a “movement moment” together—help them try countertop push-ups, go for a short walk, or remind them to stand up during commercial breaks. Small actions send a big message: their strength matters, and you’re there to support it.

For Oncology Professionals: 5 Talking Strategies to Bridge the Gap

1. Normalize Movement Early and Often “Just like we talk about managing side effects or planning treatment, we also talk about movement. It’s not about running marathons—it’s about helping your body heal.”
2. Connect Exercise to Specific Patient Goals “You mentioned fatigue and wanting more energy. Light strength training and short daily walks can directly improve both. Let’s talk about how to get started safely.”
3. Reframe Rest with Recovery Movement “Rest doesn’t mean stillness. Low intensity, targeted movement can actually reduce fatigue and help your body recover from treatment improve your sleep.
4. Use the Evidence to Build Confidence “A recent study showed that people who added physical activity after treatment had a 28% lower chance of recurrence and lived longer. It’s a powerful tool we don’t want to overlook.”
5. Prescribe, Don’t Just Recommend “I’m writing you a referral for a certified cancer exercise specialist—and here is an excellent YouTube channel to get started with today.”

The Bottom Line

Muscle is more than mass – it’s a survival organ.
Movement is more than motion – it’s a prescription.
And physical activity is no longer optional in cancer care – it’s essential.

                                Written by Sami Mansfield

References

• Huang Q, Wu M, Wu X, Zhang Y, Xia Y. Muscle-to-tumor crosstalk: The effect of exercise-induced myokine on cancer progression. Biochim Biophys Acta Rev Cancer. 2022 Sep;1877(5):188761.
• Ligibel JA, Bohlke K, May AM, et al. Exercise, Diet, and Weight Management During Cancer Treatment: ASCO Guideline. J Clin Oncol. 2022;40(22):2491-2507.
• Mialich MS, da Silva BR, Amstalden BT, Elias J Jr, Jordao AA. Association of skeletal muscle quantity and quality with mortality in women with nonmetastatic breast cancer. Discov Oncol. 2025 Feb 27;16(1):247. 

Sami Mansfield is an exercise oncology and lifestyle medicine consultant with endless curiosity and persistence. As the founder of Cancer Wellness for Life, Sami has dedicated her career to empowering cancer survivors and clinicians through innovative, evidence-based programs that improve health outcomes while optimizing cost-efficiency.

Sami is a contributing author to groundbreaking guidelines, including the ASCO Guidelines on Exercise, Nutrition, and Weight Management, and has helped shape numerous state cancer control plans.

She is the current chair of the Cancer Member Interest Group for the American College of Lifestyle Medicine, where she drives forward initiatives emphasizing the connection between science and implementation. Her patient-facing programs like BUILD and My Lifestyle Shift have reached global audiences, transforming lives through the pillars of lifestyle medicine.

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